Sunday, June 26, 2016

Investigation

After the highs and lows of last week, it was time to start the investigation into whether or not we can get the Paramount back into operation.  During the week we had done a lot of reading and research - slightly worryingly SoftwareBisque - the manufacturer of the mount had informed us that it would be unusual for a firmware glitch to cause failure of the serial communication.

Testing the serial line
We started by checking the serial connection - we had borrowed a serial tester from Tim Natusch - and connected it inline.  We had hoped to see DSR (Data Set Ready) and CTS (Clear To Send) lights - indicating that the mount was ready to communicate.  We didn't - however this didn't upset us too much as many devices don't bother with these connections and use a basic "3-wire" protocol (Rx,Tx,GND).

Next step was the SoftwareBisque MKSER utility - still no internet at the dome, but we brought it along on a USB stick.  Quite typically (remember Murphy - he's never far away) - trying to run the software gave us a "DLL Not Found" error.

As Tony, Jonathan and I "fondly" recalled stories of "DLL Hell", I tethered my Macbook to my phone and set about finding the offending DLL files and transferred them to the Dome PC.

Once up and running (and after I'd worked out how to switch the active COM port in the utility) I quickly discovered the mount in fact DID seem to be communicating - though only the DEC board, not the RA.  After a restart of the mount, we could see that both boards were communicating, and we could even initiate a "home" in both axes through the software.

This was indeed excellent news - as it meant that the basic underlying serial communication to the control boards was working, and the control boards were able to drive their respective mount axes.  As a test, I disconnected MKSER (whilst it was working) and started up TS6.  TS6 failed to connect - and then I discovered that the MKSER utility was now unable to communicate too.  A restart of the mount brought it up again, and I also proved that TSX caused the same issue as well.
Inside the Paramount GT-1100S

Since I also had a copy of the firmware for the mount, we had decided that reloading the firmware was a sensible option.  From the research we had done we knew we had to set a DIP switch on the control boards to PGM (Program). Whilst I was doing the tests above, Tony set to the mount with a hex key or two to removed the side plate covering the mount innards.

After carefully levering off the side of the mount it was easy to see the three internal boards and all the cabling.  We were quite encouraged that there didn't seem to be too much dust, dirt or insect activity in there.  It wasn't immediately obvious though where the programming switch would be - and the boards were certainly not all that easy to get to.

Now where is this DIP switch?
 Eventually though we did locate the correct switch which was on the right-hand board, mad a little harder to see clearly due to the OTA being on that side of the mount in its home position (as you can see in the photo of me peering in there with a torch)

The sporadic rain showers of the day didn't really help as we couldn't really have the dome shutter open most of the time to help with getting some light on the subject - good job we had plenty of torches!

DIP switch located, we set it into PGM mode, told the software where to find the file and hit the "download" button to reprogram (and hopefully re-initialise) the RA board.

Those of you playing along will immediately realise that good old Murph' wasn't gonna let us off that easy.

"Error 1008"

Hmm.  Let's check the firmware.  We were uploading 1.1.45 (same as the previous version).
"Version 1.0.2"

Bugger.  What now!? Back to the laptop and the SB support forums - it turns out that whilst the version of MKSER we have specifically says it supports the GT-1100S - it doesn't actually support uploading to the MKS3000 and an older version is needed.  Naturally that version is not available for download.

Long story short (well short-er!) - without the earlier version of MKSER, we're stuck -I've emailed and forum posted to SB to try and get a copy, and Grant C is going to check his old hard drives from back then to see if he might have a copy from 2002 when the firmware was last updated.

Scariest part was realising that with the mount in a state without the correct firmware loaded on one of the boards, we had to power off (and disconnect).  I was a little worried we might not get connected again.  Biting the bullet we powered off, reset the controller to RUN and powered back on.

RA Board didn't connect.

Mount would not joystick or home in RA.

Rather than panic (or cry - either of which would have been perfectly reasonable at this point!) I powered off and switched back to PGM.  Communication established again to the RA board (but still reporting 1.0.2).  Looks like we *really* need that older MKSER.

With nothing further we could really do with the mount at this stage, we replaced the cover (can't have the spiders finding a new place to set up home) and powered down.  Hopefully we can get the software soon.

Keeping the cables under control.
With no more mount stuff to do I decided to check a fault that Jonathan had reported with our new dehumidifier - it had stopped going and was showing an error. Turns out the "error" was "tF" and it meant "tank full" and indeed the water tank was full - meaning the permanent drain wasn't draining. Turns out that as well as a screw fitting cap, there was a rubber bung I'd failed to remove as well!

Finally, Jonathan had purchased a couple of surge protected power boards the week before.  Since we'd had a few power outages and electrical storms over the past couple of weeks, it seemed like the sensible thing to do would be to make sure that a power surge didn't end up as the next drama down on the list.

I took the opportunity to tidy the cables around the pier a little more by mounting the new power board and all the associated power supplies on a board bolted to the pier.  Much tidier and off the floor, this arrangement will also mean that the equipment will be a little more protected in the event we get a leak in the dome. As a bonus, the new boards have also got USB charger sockets - must add microUSB and lightning charger leads to the list to so that we can keep our phones topped up whilst working out there.

Steve

Monday, June 20, 2016

Murphy Strikes Back

Anyone who has heard me talking about Kumeu Observatory recently will be familiar with the concept of how Murphy's law operates at full strength in Astronomy - and in particular - with our work out at Kumeu.

After a really positive and productive evening a few nights previous, Jonathan, Tony and I spent an initially productive and hopeful time out at Kumeu during the day on Sunday which ended with a new major issue for us to address.

On the productive side, we manage to install the new dehumidifier that we had purchased.  The model we bought is compact and wall mounted so it keeps out of the way.  We managed to find a perfect location for it inside the dome in a position that allowed us to pass the drain hose through the wall (after a quick trip to Mitre10 for drill bits and silicone) and directly into a drainpipe.  The dehumidifier is set to target a particular humidity level (so it's not running all the time) - we've set this to 70% for now and we'll adjust as necessary to keep it dry without consuming too much power.

We set about more investigations of the Zone of Death issue - First step was an update of TheSkyX (TSX) to the latest version (which made no difference) - so we carried on - particularly wanting to confirm or deny the possibility of the previously broken cables being the source of the error (the hypothesis was that at certain mount positions we may be extending the cables for one of the encoders).  With the covers off we could see a few important points,

  1. No movement of the mount seemed to be overextending any cables
  2. Tracing the set of cables that got damaged, it as clear that all the cores on the multicore ribbon cable/connector (except 4) were used for the "passthrough" cabling (power, serial and parallel connectors), and not for any mount control.  The 4 cores that were in use were for the home position sensor (working fine) and the motor, encoders etc were on seperate cables that were not damaged.
  3. For the future, it was noted that most of the cable bundle was completely unused - so if we ever do have to pull the mount apart in future, we should probably remove it all and replace with modern power and USB
Confident that a physical cable issue was almost certainly not the cause of the ZoD we set about running more tests.
  • The ZoD covers an area around the South/SouthEast in the sky
  • We could always slew accurately to any location within the ZoD without issue
  • Once in the ZoD, we can use the joystick and accurately navigate the scope around the ZoD and the mount continues to accurately track position back to the computer.
  • If we joystick out of the ZoD, we can slew to a new position (in or out of the ZoD) no problem
  • If we try to slew from the computer at all (even a 1 arcsecond "jog") we see the following
    • Mount does a slow move in RA - much more than it should
    • at the end of this, the reported position back to the computer is send back - radically different to what it should be, this puts the mount completely out of sync
    • The mount then "continues" the slew into an incorrect position 
  • From here, the mount will now slew anywhere in the sky - apparently "accurately" but completely out of sync (so not the same part of the sky the computer thinks it should be) - including into and out of the ZoD
  • The new incorrect position appears to be largely out in RA and out to a lesser degree in DEC
This behaviour led us to think that, as we were starting to consider the other night, that software might be an issue - Either TheSkyX (still, even though we had updated it) or the firmware on the mount itself.

Then we had (what we though was) a major breakthrough - we tried TheSky6.  And it worked. No ZoD issues at all !!!.  When we switched back to TSX the ZoD returned.  We were very hopeful that the whole thing was just a software glitch on the PC.  We set about completely removing and reinstalling TSX from scratch.

When we had done this, very hopefully, we tried again.  This time, the behaviour was not quite the same - there was no longer any random slews from within the ZoD.  Yay.!!!!  However, there was actually no slewing AT ALL once we entered the ZoD - Boooooo!!!   We could still joystick (and issue move commands from TSX) but no slewing to a target. 

Clearly something in the communication between TSX and the mount had to be at fault.but what? and what was different in the reinstalled version that made the behaviour different?

Checking through the mount configuration in the "BisqueTCS" panel, the only obvious thing was that the mount was apparently reporting that the "Hemisphere Setup" was set to "not configured".  Knowing we'd previously selected "Southern" (of course) when we initially set up TSX for this mount, I clicked this option.  The mount disconnected (as expected) and then the TSX software froze up and then crashed.  After reloading the mount was connecting ok, but seemed not to be quite functioning correctly - for some reason the joystick was only allowing the mount to slew in DEC. 

Thinking the hemisphere setup routine had not completed, I tried again (though selecting Northern Hemisphere to ensure it changed).  This worked properly - the mount disconnected, then connected again and it seemed to clear the issue up.  Of course I then needed to ensure we went back to "southern hemisphere" mode, so I again selected this option. 

The mount disconnected, and reconnected - but would not respond correctly to a "home" command, giving an error that the motors we currently operational.  We restarted everything - but this time the mount would not reconnect to serial control. The mysterious issue where the mount would not joystick in RA was also back.  The mount did respond to a "home" command (double click of the joystick) though - proving both axes were still controlable. 

After another full power off restart of everything (this is my IT support background kicking in) we learned that sometimes, after a power cycle and the initial "home" command, the mount would start and the RA would work and the DEC not from the joystick.  Sometimes it was the other way round.  Sometimes both both work.  Unfortunately serial communication doesn't seem to be working at all now.......   We tested the serial port, and switched ports with the Optec TCF to make sure the PC hadn't locked out the COM port for some reason. No Joy. 

Frustrated and annoyed we shut everything down and went home.  Next steps is to attempt to recover from this situation.  There is a utility that permits a lower level communication with the internal control board that we can try - possibly to reload the firmware.  There are also, I believe, further options for programming the control board (the MKS3000) directly - so we've not lost all hope!

That said, we really are starting to tire of Murphy's Law of Astronomy - it seems that just as we are getting some serious leaps forwards-  we get our biggest setbacks.... 

Steve




Friday, June 17, 2016

A Productive Night

Last night Steve Hennerley and myself meet up at Kumeu Observatory, it ended up being a very productive night, we did some tests on the "Zone of Death" and our current theory is that it's not a hardware issue but has something to do with the Sky X, Steve noted that our version of the Sky X was out of date so maybe by reinstalling the latest version of the Sky we might be able to resolve the issue, the evidence for the Sky X being the problem has been mounting with the Sky X randomly losing synchronisation and the home position, also slewing through the "Zone of Death" with the joystick has no adverse affect and there has been some weird flipping of the way the Sky X displays the sky when zooming in on a targets lately as well.

One of the first things we did was calculate the focal length of the telescope, Grant Christie had suggested we fill in all the configurations in MaxIm DL so that they will get picked up by the fits header after I had sent him some test microlensing images the other day, so after a bit of calculating we entered the focal length and aperture of the telescope and the latitude and longitude of the Kumeu Observatory site, the only thing we didn't enter was the % of the central obstruction, Steve said he would bring out his digital calipers next time so we can measure it accurately.

With the sky being so clear last night we decided to have a go at collimating the telescope, the telescopes collimation has degraded recently probably from all the times we have had to take the OTA off the mount, so it was good to see that it was not the "astronomical seeing" that was causing the bad focus results I've been getting recently, after spending a bit of time getting the collimation refined using the open star cluster method and then some single semi bright stars, Steve noted that we had got the collimation as good as we could using the methods that we had at our disposal but that we could improve the collimation even more using a program like CCD Inspector, we would have downloaded it and installed it on the night but the internet is still not working out at Kumeu Observatory so that's another issue that still needs to be resolved, after doing as good a job as possible refining the collimation we could see a definite improvement in the auto focus results.

The next thing we got onto was getting the Pin Point Astrometry to work in MaxIm DL, after Steve got that working I was delighted to see that we can now use the "point telescope here" function in MaxIm DL, this is a really helpful option when wanting to center an object in an image in MaxIm DL so you don't have to waste time jogging the telescope.

After that we got onto trying to get the internal Auto-guider of the SBIG ST-10 XME to work, after a bit of investigating Steve managed to get the Auto-guider working, this is a huge step forward for us because we are now not limited to 100 - 200 second exposures, after Steve went home around 2:30 am I took some test images, the stars looked nice and round in both 5 minute and 10 minute exposures, needless to say I was very happy with the results.

All this fantastic progress was tempered by the discovery that we have mold growing on the inside of the corrector plate as well as on the primary mirror so we are going to have to take apart the OTA to be able to clean the telescope up, Steve suggested we might even want to try get the primary mirror re-aluminized while we have the OTA apart, we could even look to flock the interior of the optical tube seeing as we will have access to the interior of the tube, the outside of the corrector plate also needs a good clean as well.

We did notice a fair bit of condensation in the dome over the night so we plan to get out to Kumeu over the weekend and get the recently purchased dehumidifier installed to deal with this problem, I have also purchased two surge protectors so we can protect all the equipment from any electrical faults as well, as we have had a fair amount of power cuts out at the observatory over the past few months as well.

Also when I was shutting down the dome at 5 am, I put the telescope back to the home position to find that the Sky X had again lost it's home position, the telescope was in the home position but as far as the Sky X was concerned the home position was up near the zenith! I have no idea why the Sky X is randomly losing it's synchronisation but this is further evidence that perhaps we do have a problem with the software, it might be solved by simply updating the Sky X to the latest version or maybe we will have to reinstall the drivers I'm not sure, so even though we still have a few issues to work through I went home very satisfied that we had made some fantastic progress.


Ten minute auto-guided test exposure of the Eagle Nebula, the brighter stars all showed signs of bleeding as you would expect from such a long exposure but I was really happy to see the stars stay so spherical over such a long time. ^

Posted by Jonathan Green

Tuesday, June 14, 2016

1st Attempt at Microlensing

Last night after the Auckland Astronomical Society meeting I headed out to Kumeu with the coordinates of a current microlensing event thanks to Grant Christie and Tim Natusch, over at Stardome the sky looked good so I was looking forward to having a go at finding the star field and taking some images using the Kumeu equipment, after traversing the road works that had shut down the North Western Motorway I finally arrived at Kumeu to find the weather was nowhere near as good as it was back in the city, after waiting out a bout of heavy cloud I opened up the dome and attempted to get good focus, all my focus attempts were giving me results of very poor seeing (FWHM of 5.6) so after a few attempts I figured that the seeing might actually just be bad which was later confirmed by seeing very bad scintillation overhead, by this time another bout of heavy clouds arrived and this time brought significant rain so I was forced to close up the dome, instead of packing it in I decided to at least enter the microlensing coordinates into my chart elements so at the next opportunity I would be ready to point at the correct star field, while waiting for the sky to clear I also set about capturing new calibration files seeing as the camera can now stay consistently down at a temperature of -20, the sky did clear but by the time I had opened the dome and slewed to the field took a couple of test exposures the sky had clouded up again and started to rain again, so frustrated I was forced to close up the dome again and went back to capturing calibration images, this was the pattern of the night mainly clouds and rain with the odd sucker hole that quickly closed up before anything useful could be done, I should have just stuck to taking calibration images for the rest of the night as it ended up being a waste of time trying to get work done in the few gaps the clouds provided, I think if the conditions had been better I would have been on target and capable of capturing some useful images, so it was a great learning exercise and at least we now have some new Dark and Bias frames for calibration, by 4 am I closed the dome up and headed home, I had no way to check the weather reports as the internet was still not working but I think I made the correct call as it was still raining when I got back to my house in Coatesville.


In the foreground you have Jennie McCormick's old dome with Kumeu Observatory in the background, overhead rain clouds kept me on my toes all night, I don't think I've ever opened and closed the dome as much as I did last night so that was good practice for being able to close the dome quickly when rain showers passed by. ^

Posted by Jonathan Green.

Monday, June 6, 2016

New Cooling Fan Installed.

After having the cooling fan of the SBIG ST-10 die last Wednesday, I took the camera off the OTA on Friday night and took it into Stardome for Tony Burns to take a look at, after running some tests Tony could see that thankfully it was just the fan that needed replacing, Tony Burns found a replacement fan at Jaycar on Saturday afternoon and installed the new fan as well as putting some loose parts back together on the camera. On Sunday afternoon I dropped by Tony's to pick up the camera and that night I re-installed the camera on the OTA, after turning on the camera I was delighted to see it get down to -20 quickly and stay at -20 consistently with power consumption hovering around the 50-60% mark, this is fantastic as I can now set about collecting a new set of dark and Bias frames at -20 for calibration, the seeing was not fantastic on the night with a FWHM of 4.3 being the best I could manage on the night! after getting as good a focus as I could get, I set about doing a re-calibration of the best T-Point model that I had taken a while back, after capturing 17 re-calibration sample points, the pointing was back to being either on the crosshairs or within a few arc seconds of every target.

As well as bad astronomical seeing there was also quite a bit of high cloud around as well, you could easily see the fog filter effect on the brighter stars with the naked eye, even though it was not the greatest conditions for imaging I set about capturing some targets, I imaged Comet 9P Tempel as well as 116P Wild then moved on to taking some images of galaxies and nebulae, the clouds became thicker around 4 am in the morning so I closed up the dome and headed home for some much needed sleep.


Sombrero Galaxy 60 x 60 second exposures of luminance stacked. ^


Part of the Trifid Nebula captured with 60 x 20 second exposures in the Red filter stacked. ^

Posted by Jonathan Green

Thursday, June 2, 2016

Problem with the cooling fan of the SBIG ST10-XME

After a very wet day the sky finally cleared up after dusk so I went out to Kumeu to take back the Optec TCF unit that had been recently upgraded to be re-installed and tested, the first thing I noticed was that the cooling fan of the SBIG ST10-XME CCD camera was no longer working, at first I thought the camera was dead as it was not making any sound (the fan is quite noisy) but after having a look with the hand torch I could see that the camera was on and it was just the fan that wasn't moving, it would occasionally do a turn or two but only slowly and intermittently, there has been at least two power cuts out at Kumeu since I've got back from the RASNZ conference so I'm not sure if that was the cause or if it's just that the fan needed replacing after not being used for years, certainly the cooling of the camera has been an issue as I have reported in previous posts, with the camera not being able to get down to -20 over Summer or Autumn.

Seeing as I had the dome open already I took some images with the camera to just confirm that it's still working and thankfully everything seems fine except for the fan, not wanting to try cool the camera down without the fan I just tested the TCF with the camera at ambient temperature, the upgrade of the TCF seems to be working fine, although I didn't get great focus thanks to passing clouds and what looked like some bad seeing (the stars seemed to be scintillating a lot which is a sure sign things aren't steady up there) but at least the auto focus worked fine so hopefully the upgrade will see an improvement in the performance of the TCF from now on, I will have to ask Grant and Steve's advice on how to proceed with the camera's fan, hopefully it just needs a new fan but I can't rule out that it may be an internal electrical fault, I think it would be wise to install some form of power surge protection in the near future to just safe guard the equipment, I hope we can get this sorted quickly and that it won't cause too much of a delay in our progress out at the observatory.

Posted by Jonathan Green

Wednesday, June 1, 2016

Optec Temperature Compensating Focuser Upgrade

The weather has been rubbish in Auckland of late, stormy conditions have kept me from opening up the dome since getting back from the Royal Astronomical Society of New Zealand conference, so we haven't had much to report for a while, last night I took in the Kumeu observatories Optec Temperature Compensating Focuser (TCF) for a ROM chip upgrade at Stardome Observatory, Grant Christie had sourced us a new ROM chip and Tony Burns preformed the upgrade, hopefully if the sky clears up tonight I'll be able to test out the upgraded TCF, we have also bought a new dehumidifier for the observatory to help protect the equipment from corrosion so hopefully we will have that installed and operational soon as well.


Tony Burns installing the new ROM chip. ^


Tony Burns checking his handiwork. ^

Posted by Jonathan Green.

Monday, May 16, 2016

Day and Night at Kumeu Observatory.

On Saturday the 14th of May myself,Tony Burns and Steve Hennerley met up at Kumeu Observatory to see if the dome slave issues could be resolved, I'm happy to report that with Tony's expertise the dome now stops at home and can be parked again, so now it should just be a matter of refining the parameters to get the dome slaved to the telescope properly, Tony did mention that he wasn't really that happy with the setup and is already making plans on how to best improve the dome slave situation, Steve also managed to find the problem with the dew strap it was just a wire that was loose so that's all fixed now so dew shouldn't be a problem anymore, while we were testing the dome rotation a new problem with the dome motor became apparent it was really making some jerking movements that none of us had seen before, after some inspection Steve discovered that one of the bolts had worked it's way loose, so he jacked the dome up a bit so we could take the motor out and repair it which Steve did without much issue, this was really lucky that this had happened while Steve and Tony were there as no doubt if it had happened at night when I was there by myself it would have sent me home early and been a waste of a good night.


Tony Burns working on the dome control board. ^


Steve Hennerley fixing the loose bolt on the dome motor. ^

One thing that happened while we were trying to refine the parameters of the dome was that when Steve was driving the telescope around with the Sky X it kept on trying to point at the ground, we couldn't figure out why it was doing this at the time, at this stage it was getting late in the day and Steve's daughters who had been very well behaved all day were starting to become a little bit restless so we called it a day and all headed home, after making myself something to eat I headed back out to Kumeu by 7 pm, after setting up I discovered that the Sky X no longer knew where it was pointing in the sky, when the mount was in the home position the Sky X thought it was pointing up near the zenith, so no doubt this was the reason why the telescope had been trying to point at the ground earlier, after ringing Steve to discuss the problem I set about doing a resynchcronisation, the 1st problem I ran into was the finder scope was not even closely aligned anymore as we had taken it off the OTA a while back, trying to center a star without the finder scope aligned is like trying to find a needle in a haystack! So after further discussion with Steve he suggested I align the finder scope on the Moon, but even with the lowest exposure I couldn't see any detail on the Moon, I was a little bit exasperated as I was thinking that I might have to go home and grab my diagonal and eyepiece and have to take off the CCD to just get the finder scope aligned, thankfully I got lucky as some thick clouds rolled in, they acted like a Moon filter and allowed me to see detail on the Moon so I found a large crater and managed to align the finder scope on it, I think this must be the very first time that I was actually happy to see the clouds come rolling in.


Moon image captured with heavy clouds acting as a filter that allowed me to see surface detail and align the finder scope. ^

Now that the finder scope was aligned I set about synchronising the Sky X on some bright stars, through gaps in the clouds I managed to synch to nine bright stars before the rain arrived, this seemed to do the trick as now the Sky X knew where it was, I have left the finder scope on the OTA just in case Grant or Steve thinks we might need to do more star synchronisation than the nine I managed to get, in fact I was thinking that perhaps the problem with our slewing in the zone of death may be due to never having done any synchronisation in that part of the sky before, the rain was quite heavy at this stage ( 10 pm ) so after packing up I headed home to relax, by midnight things had cleared up again, after consulting some satellite images I figured I had maybe a 3-4 hour window of clear skies to work with so I headed back to Kumeu and got back to work, the sky was fairly clear when I arrived so I set about capturing a new pointing model, I managed to capture 230 samples before I ran into the zone of death as sample points must have drifted into this area, so I finished and saved the pointing model before re-homing the telescope, I then turned the pointing model into a super model and found that it just dropped the last sample just like last time so I had 229 good samples to work with, I noticed that the RMS wasn't quite as good as the last model I captured but I think this may have been due to the sky conditions not being as good as last time, the astronomical "seeing" wasn't as good and I did have to image through thin passing clouds from time to time, even though the Sky X had no trouble solving all the images I suspect this may still have had an adverse effect.

After converting my pointing model into a super model and turning on the Pro-Track function so the model could make adjustments to the Paramount's tracking, I set about testing the accuracy of the new pointing model, again I was very impressed with the accuracy of the model with objects either directly on the crosshairs or just a couple of arc seconds off from it, I'm going to have to monitor the tightness of the shipping bolts on the C14 as any movement in the primary mirror will of course cause the pointing accuracy to deteriorate over time, if this is the case and we do discover that the primary mirror is indeed displaying signs of movement then I'm hopeful that adding locking nuts should resolve the issue, after doing quite a few pointing tests I noticed that the clouds had rolled back in, so I closed up the dome just in time before another heavy rain shower came rolling in, it was 3:40 am by this stage so I just packed up and headed home to catch up on some sleep.


Pointing test of Comet 116/P Wild with a 100 second exposure at 2x2 binning. ^


Pointing test of NGC 5643 the image is a median stack of 4 x 200 second exposures at 2x2 binning. ^

Posted by Jonathan Green

Friday, May 13, 2016

Windy Night at Kumeu

Got out to Kumeu Observatory last night to find the conditions were atrocious, strong winds and fast moving clouds had me heading home without opening the dome, I figured it might calm down after the Moon had set so I set my alarm and took a nap, I must have been quite tired as I slept through my alarm, luckily I woke up early in the morning, conditions looked better from my house so I headed back out to Kumeu, when I arrived conditions were only marginally better the wind was still really strong but at least there wasn't as many clouds about, up at the gate the wind was gale force but down the hill were the observatory is located I felt it was sheltered enough to risk opening up the dome.

There must have been a power cut out at Kumeu since the last time I was out there as the computer was off, after booting up the computer and cooling down the CCD I set about doing an auto focus run, but found that the focus was way off, it must have been due to the power cut knocking out the temperature compensating focuser, after putting the focus back to the last known focus point, I attempted to do an auto focus run, but I couldn't get a v- curve as the auto focus was trying to step past 1 which it can't do to complete the curve, knowing that the only way to fix this was to put the temperature compensating focuser back to the half way point of 3500 and manually focus the C14 back to a close focus point, I was really loath to do this as this meant I had to undo the shipping bolts to move the primary mirror and doing that would no doubt ruin my last pointing models accuracy but seeing no other option I ended up having to do just that, having got the C14 back into near focus I then went to an 8th magnitude star and finally got an auto focus v-curve to work, now the focus is sitting around the four thousand mark so hopefully I won't run into this problem again, I also noticed when I was undoing the shipping bolts that one was kind of loose, I had only done them up finger tight before and to be honest I was really gentle about it as well, so this time when I tightened up the shipping bolts I made sure they were really robust and as tight as I could get them by hand so hopefully they will stay tight or else we might need to source some locking nuts to keep the shipping bolts in place.

After all that was completed I turned my attention to seeing how badly my pointing models accuracy was affected by moving the primary mirror and just as I predicted it has had an adverse effect, now objects are around five arc minutes away from center, so next clear night I'll have to do a new pointing model, I spent the rest of the night testing out the tracking of the Paramount GT-1100S and I've got to say I'm really impressed with how well the mount tracks unguided, I could get 200 second exposures in most places in the sky so this is looking good, no doubt with auto-guiding we will easily be able to extend our exposure times, at astronomical dawn the winds really started to pick up again so I closed and clamped the dome and headed home around 6am.


NGC6000 a galaxy in Scorpius the image was a tracking test and is a stack of 11 x 200 second exposures, calibration files are out of date and the "seeing" was bad on the night so image quality is not the best. ^


Pointing test of Comet 116/P Wild, all objects are roughly in the same spot as this comet being around 5 arc minutes left of center, the image is a single 200 sec exposure, the streak through the center is from a passing satellite. ^

Posted by Jonathan Green

Wednesday, May 4, 2016

A Perfect Night

Got out to Kumeu Observatory last night and was happy to see the conditions were much improved from the Monday night, I measured my focus star with a full width half maximum of 2.1! this is the best focus I've ever recorded with the C14 so it must have been pretty decent astronomical "seeing", hopefully after we refine the collimation we will be able to get even sharper images, with the conditions being so good I set about capturing a new pointing model and this time I isolated the south east portion of the sky thanks to advice from Grant Christie who dubbed this region the "zone of death", I was ecstatic to see all the pointing samples solve without issue, I had almost completed the entire model when I got my 1st fail it was up near the zenith in the east, the point was probably just a little too close to the dreaded "zone of death" so I aborted the slew and saved my model which at this stage was up to 209 pointing samples, I then converted the standard model into a "super" model and was pleased to see it only dropped one sample, it was the sample captured just before the fail, I was really happy to see that as when I attempted to turn the previous night's model into a "super" model it dropped 130 odd samples! so feeling like I've finally got over the hump in regards to capturing a robust pointing model I set about testing the new model.

I imaged targets in all areas of the sky including the "zone of death" and was really pleased to see that targets were either on the crosshairs or just a few arc seconds to either side of it, so I'm thinking we finally have a really decent pointing model to work with now, I'm also feeling much more confident about the whole T-Point process so if I need to capture a new model in the future it shouldn't be a problem, I've enabled the pro-track feature and it seems like the tracking has improved some what, in some parts of the sky you can easily get 200 second exposures without any noticeable drift.

All we need to do now is concentrate on getting the auto-guider working but this should just be a simple matter of sourcing the correct cable, we also need to replace all the filters in the SBIG as when we had the camera off when the mount was being repaired we noticed mold growing on them, thankfully there was no mold on the CCD sensor itself, the dome slave issues need to be resolved and the collimation of the C14 needs to be refined, after all this has been taken care of we should be ready to do some research grade astronomy.

Below are a couple images from the night, note that the calibration is not really effective anymore as all calibration files date back to Summer so I'll need to replace them with new calibration files soon ( I'm just waiting on the new filters to arrive )



Pointing and tracking test of the Sombrero Galaxy, the image is a 200 second exposure and is un-calibrated, weird stuff near the edges might be from the mold? I'm not sure. ^



Pointing test of the Southern Pinwheel Galaxy, this image is a median stack of 11 x 100 second exposures, the image was also calibrated. ^

Posted by Jonathan Green

Tuesday, May 3, 2016

Fog and Dew.

Last night was the best night in ages so after taking care of some commitments for the Auckland Astronomical Society I headed out to Kumeu Observatory, I was a bit discouraged when I arrived in Kumeu to see that the fog was really thick, I could barely see a few meters in front of my car even with the fog lights on! Thinking that I would show some perseverance I set about setting up, the fog was well above even the tallest trees and so thick that with the naked eye I could only see the brightest stars so after taking some test images I realized I would have to wait for the fog to thin out a bit.


The state of the Fog when I arrived at Kumeu Observatroy ^

As the temperature started to drop around midnight the fog finally started to settle down, it was still really thick in the east so I decided to start my pointing model in the west, I opted to make a really dense pointing model as I had no idea how long it would take for the fog to lift in the east, everything was going really well and I had astrometrically solved over 150 odd samples without issue until all of sudden the images would no longer solve, what turned out to be the problem was that the correcter plate on the C14 had become "fogged" up due to the dew, earlier on in the night I realized this might be an issue so I had turned on the dew strap to full power as a test to see if it would keep the dew off all night, but to my hand the strap still felt cold after hours so maybe it was never re-connected when we put the OTA back on the mount, at any rate it was not keeping the dew off at all.


Dew on the corrector plate ^

I didn't want to give up but I was also now in a part of the sky where the star density was low, so I lowered the detection threshold in T-Point and increased my exposures to 10 seconds, I then stepped to a higher up part of the sky where the effects of the fog were the least, this seem to do the trick as I managed to get up to 182 sample points, it was 3 am by this stage so after getting almost all the western side of the sky I turned the telescope towards the east, the fog had finally started to settle down a bit so I figured I might be able to continue on until dawn but as soon as I took my 1st image in the east I got hit by an error message saying that "The mount is at a minimum or maximum position limit and cannot be slewed. This error may be the result of improper synchronization near the meridan. When syncing near the meridian, be sure the optical tube assembly and the synchronization star are on opposite sides of the meridian. ".


Error message ^

I tried to continue the pointing model but the mount had become confused and attempted to point the telescope at the ground so I aborted the slew and finished and saved the pointing model before "homing" the telescope,
even though I was annoyed that I couldn't finished the pointing model I was happy with how many samples I had captured, so hopefully next time I'll get the entire sky, I tested the pointing model and found it was extremely accurate in the western side of the sky as you'd expect with every target being right in the middle of the crosshairs, the eastern side targets did not fall in the center of the frame though so a new pointing model will have to be done of course, the images at this point were pretty bad due to the dew and with no way to de-fog the corrector plate I closed up the dome and headed home around 4 am.


Pointing test of Omega Centauri ^


Pointing test of NGC 4945, image quality had really deteriorated by this stage ^


The fog had settled down a bit by early morning but as you can see it was still very foggy conditions. ^

Posted by Jonathan Green




Thursday, April 28, 2016

Pointing Model Issues in the South East & Dome Slave Issues

Got out to the observatory early last night which was lucky as the clouds rolled in by 8:30 pm, after setting up I ran an auto focus run in MaxIm DL and got a full-width half-maximum measurement of 2.8 on the focus star, so it must have been better "seeing" than the previous night I guess, I then set about doing a new pointing model but this time I started on the eastern side of the sky, unfortunately every time the mount pointed towards the south eastern part of the sky the mount would become confused and want to point towards the ground, so I'm now thinking this it's not a mirror flop issue at all, it only seems to happen in this part of the sky, once it happens the mount will not point to anything accurately again until it has been homed again, which I know you can't home the mount while doing a t-point model as this will change the parameters, so this is an issue that will need to resolved if we ever plan on capturing a dense full sky pointing model, I'm really perplexed as to what could be causing this problem, it's the same problem that stopped my previous nights pointing model run after already capturing 56 sample points!

After attempting a pointing model on the eastern side a few times with the same result the clouds came rolling in and put an end to any further attempts, so I just re-loaded the previous nights pointing model and slewed the telescope around a bit with the dome slaved to see if I could refine the parameters so that the telescope would be pointing in the middle of the shutter every time as Steve had shown me how to do that, before I could make any adjustments though, the dome started to inexplicably stop stopping where the telescope was pointing, it would just continue around and around doing full rotations until aborted in the Lesve Dome control, so it was being a bad slave to say the very least! I homed the dome but then found the dome would no longer park either, so being a bit frustrated and having no idea how to fix the problem I just closed up up the observatory and headed home.


Clouded out with barely a star to point at, I headed home early ^

Posted by Jonathan Green

Wednesday, April 27, 2016

Auto Focus Issues Resolved and New Pointing Model

Got out to Kumeu Observatory a bit late last night but ended up working until 5:30 am so it was a pretty productive night, first thing I did after setting up was to loosen the shipping bolts in the C14 so I could move the primary mirror, once that was done I attempted to do an auto focus run in MaxIum DL but for some reason it would focus on a hot pixel and not the stars on the frame, so guessing that I needed to get it closer to focus manually I proceeded to focus the telescope as best I could, after getting the stars as focused as best I could I then selected a star and attempted another auto focus run but again it would just take loads of images and then fail due to too many exposures even though I had entered the parameters that Grant Christie had suggested, feeling a bit frustrated and thinking that the focus was probably good enough for a pointing model I switched the camera control over to the Sky X and attempted to do an automated calibration run, the newly slaved dome couldn't keep up with the randomized pointing model so I ended up manually moving the dome which worked fine, the problem I run into was that after 20 or so pointing samples it would stop astrometricaly solving the images, after a couple of attempts I noticed that the temperature compensating focuser was not tracking the changes in temperature and I knew this was a problem, so I figured I better try resolve the focusing issue before attempting another pointing model, after attempting a few more auto-focus runs I noticed that the focal ratio in the focus setup was in error so after entering the correct focal ratio I was overjoyed to see a lovely V curve and got my 1st auto focus successfully completed, I measured the full-width half-maximum of the focus star at 3.548 which isn't that bad considering we haven't collimated the telescope yet.

With the focus looking better than ever I proceeded to do another pointing model, this time I got the entire western side of the sky successfully with 53 sample points I then got through 3 sample points on the eastern side before running into trouble, I'm not sure why but it could be due to mirror flop seeing as the focuser was tracking the changes in temperature at this point, what would happen is that the mount would become confused and want to point to the ground and the only way to fix that problem was to re-home the mount, knowing that you really can't continue a pointing model after homing the mount I just finished and saved the pointing model at 56 points, hopefully if the sky is clear tonight I'll try another pointing model but start on the eastern side this time and see if I run into the same problem, it was getting late by the time I finished the 56 point model but I couldn't resist testing the pointing model, at 1st the model was saying we needed to make an adjustment in Altitude but after converting the model into a super model it was saying not to make any adjustments to the polar alignment at all, so this is looking hopeful and seeing as my test images at 200 seconds were showing only the slightest of drift I figure our polar alignment must be pretty good, so I slewed to a few objects and was happy to see each object on the frame although each object was a bit off to the right of center, probably due to the pointing model not being completed perfectly and without hardly any pointing samples on the eastern side of the sky, below are two images from my pointing tests, vignetting is worse than normal due to the gibbous Moon and the calibration still needs to be re-done, I was really happy to see the SBIG CCD get down to -19.5 though, so I think as we move into Winter we should have no problems getting down to -20.


M27 The Dumbbell Nebula was a pointing test low to the horizon ^


Lenticular galaxy IC 5122 was a pointing test high in the sky ^

Posted by Jonathan Green

Wednesday, April 20, 2016

Initial Tracking and Slewing Tests

Last night I headed out to Kumeu Observatory even though the sky was fairly cloudy, I figured there were enough gaps around so I couldn't resist testing out the repaired Paramount GT-1100s, I'm very happy to report that the slewing and tracking sounds very smooth now, in fact I've never heard it sound this good before! I did manage to take some images although I had trouble with the focus, predictably the focus was out after having the OTA off the mount, so I manually got the focus close again, I then attempted to do an auto focus with Maxim DL but it failed as it wanted to go past 7000 which is the maximum amount of steps the TCF can go to, I'm not sure why this was the case perhaps we don't have enough back focus or the primary mirror might need to have the shipping bolts loosened.

Seeing more dense clouds coming in I decided to make use of the sucker holes while they were still there and took some exposures testing the tracking in different areas of the sky, I'd say the results were very promising with the tracking being even better than before the repair, I took 100 sec and 200 second exposures without any noticeable movement in the stars, although I didn't get to test all parts of the sky due to the clouds so I may have just been in "sweet" spots, we could never get 200 second exposures without star drift before the repair so this is all looking very hopeful, once we get the auto guider working we should be able to get up to 500 seconds without too much issue.

I've included some images from last night but note that after the failed auto focus runs I just manually got the focus back to being close so it definitely wasn't anywhere near perfect focus, also there was significant vignetting due to the gibbous Moon being up and the image calibration doesn't really work anymore due to the camera being taken off the OTA during repairs so no doubt we will need to re-do all our calibration files again, one thing I did notice was that the SBIG-ST10 CCD was still unable to reach -20, it did seem like a hot night but it's a bit of a concern that it still can't get down to -20 at this stage of the year.


100 second exposure tracking test ^


200 second exposure tracking test ^

Posted by Jonathan Green

Sunday, April 17, 2016

Back In Action

Finally after a brief break due to the mount needing repairs Kumeu Observatory is back in action, thanks to help and advice from Graham Beazley, Grant Christie, Marc Bos and Tim Natusch. Steve Hennerley was able to reinstall the repaired declination worm assembly successfully with assistance from Jonathan Green on Saturday the 9th of April, then last Friday night Jonathan Green and Steve Hennerley put the "Nustrini" Celestron 14' SCT back on the mount, with the S-BIG CCD camera re-attached and after spending a fair bit of time getting the balance correct they are confident that the setup is ready for action again, so bring on those clear skies!


The newly repaired and re- installed declination worm assembly ^


Steve Hennerley adds the finishing touches to the Paramount GT-1100S ^


On the Friday night we also used a Howie Glatter laser collimator which fires concentric laser circles to do a preliminary test of the "Nustrini" Celestron 14' SCT's collimation, we were happy to note that the C14 isn't too far out of collimation, so hopefully it will only need some slight tweaking to get the telescope back into perfect collimation. ^

Posted by Jonathan Green

Wednesday, April 6, 2016

New Bearings!

So after a careful examination of the dec drive assembly from the paramount, Auckland Astronomical Society's engineering wiz, Graham Beazley removed the bearings from the assembly, and after a quick trip to Saeco had new bearings for just $17+GST.

Graham reassembled and adjusted the tension and it looks like the assembly is now back in business.

Hopefully we'll get this reinstalled in the mount in the next few days and  will then be ready to get the system backup and running again !

Steve

Monday, March 28, 2016

The Unhealthy Noise....

Sorry for the lack of updates... the "unhealthy noise" reported by Jonathan has been the main focus of the observatory for the last few weeks...

Shortly after Jonathan's last post, I headed out there with him to listen to the noise (which I hadn't heard until then) and see if I could work anything out.  It didn't take too long before it became pretty obvious that something wasn't right.. .

We managed to narrow down the "noise" - which was really more like a "clunk" sound - to the declination axis - it only seemed to happen when the scope was slewing in dec. The clink noise didn't really seem to happen at the same point in the slew (which I theorised might indicate an issue with the ring gear), nor did it seem periodic enough to happen on every turn of the worm.

What was slightly worrying though is that the OTA was being visibly deflected every time there was a clunk, and you could certainly "feel" the roughness in the motion by putting a light touch on the OTA when it was moving.  As you might imagine, we didn't so this for long. My thoughts were firmly that this was a more "mechanical" issue, than any variation in the sound of the slewing caused by software/pointing model adjustments.

I really wanted to isolate there being a gear meshing issue, so I disengaged the dec worm assembly from the gear (the same process used when balancing the OTA) and commanded the mount to slew in declination again.  I recorded a video of this (not for the visuals so much as to record the sound of the issue to demonstrate to the AAS/Stardome team - so please forgive the iphone camera work!)



This was both a good and a bad result.... the good news being that it couldn't be any problem with the worm or gear as the noise still happened when these were disengaged - the bad news being that it was now even more obvious that we have a mechanical problem to solve.

The old "mechanics stethoscope' trick (using a screwdriver handle held to the ear and the "blade" touched to various parts of the mechanism) seemed to narrow down the source of the clunking sound to be the region of the dec drive assembly close to the pulley on the end of the worm shaft. This led to a working theory of a possible bearing issue.

We didn't proceed with any more troubleshooting that night but did seek help and advice from both Grant Christie and Marc Bos (Stardome Curator of Instruments), and also to assess what options we might start looking into to find parts and repair if it does end up being a failed bearing.

Another visit to Kumeu with Marc seemed to lead towards a general agreement that possibly a bearing may be the issue - but confirmation would require removal of the assembly for closer examination to narrow down exactly what the cause might be, also eliminating other possibilities such as the servo  motor.  Permission was to be sought from Stardome (who own the mount on loan to Kumeu) for this investigative work to proceed.

After agreement that the dec assembly really should be removed and examined with the aim of repair (either locally, or by sending back to the manufacturer) - Jonathan and I again headed up to Kumeu to remove the OTA from the mount again and remove the offending assembly as previously discussed with Marc.
The paramount worm shaft -there is a bearing at each end
at least one of which seems to be causing the problems

It didn't take too long to carefully remove the dec assembly from the mount. Once on the desk, loosening and removing the belts (well one of them - the other had already had to be removed with the motor to remove screws bolting the assembly to the mount) - it became obvious that whilst the motor and pulley shafts were both very smooth to move - the worm shaft was anything but...  The rotation of the worm shaft was very rough, even "binding" occasionally - certainly not the feel that precision rotating parts should have.


Next steps will be to have Marc, and our other engineering experts take a look and see if we think this is something that we can have repaired and set up locally, or whether we package it up and send it off to the US.

In other news - you might recall a few blog posts back that I had been having trouble getting a response from the dome rotation "azimuth" sensor.  Well, whilst the scope has been out of action, we took the opportunity to get electronics wizard, and dome rotation expert Tony Burns out to the site to have a look and give us his valued opinion.  We ended up removing the sensor and the board and he took it away to check.

Turns out there were a few problems with the system - so it was a good  thing we did.  Firstly there was actually a problem with the USB board itself - at some point in history a short circuit or similar had caused some damage on the board (lifting some of the copper "track").  Also - and probably unrelated - there was an issue with at least one of the input channels that needed investigation.

Tony replaced the control  ICs on the board and repaired the broken track - effectively returning the interface board to "good as new" condition.

The Azimuth sensor however was not quite a simple.  The postion of the sensor (as I've mentioned before) is very close to the dome slot in the open position.  This means that there's a very good chance that any moisture may find its way into that area (as the dome is opened, or closed, usually in that position).  Add to this Auckland's very humid climate - and there is a very good chance that corrosion might at some point give some trouble.

Looks like the connections to the photosensor and IR LEDs has corroded away - meaning there was no chance of this working!.  Tony has fabricated a new set of optoelectronics for the encoder wheel using much more robust connections that will hopefully last many years to come.

All that remains is for this all to be reinstalled and tested - and hopefully the "break" we've just been forced to have will give us the opportunity to do this over the next few weeks.

Phew... that was a big post - and that'll teach me for waiting so long between updates.  I will post more when we know what is happening with our dec assembly and hopefully when we will be back up and running....

Steve H


Thursday, February 4, 2016

Automation Elation & Slewing Problem Again

I went out to Kumeu last night determined to figure out the T - Point automated calibration run, I was setting up when I was pleasantly surprised to see Allister had turned up to set up his giant binocular Dobsonian for some observational fun, there was a few clouds about but there were also plenty of big gaps so after getting the C14 focused, I started an automated calibration run, this time I just paused the run after each image was taken of the first six sample points that were all in the start region, I then right clicked the images and astrometrically solved them via the image link feature of the Sky X, this seemed to do the trick, as every sample point after these six would automatically solve and add the sample points, needless to say I was elated to have finally got the automated process working, I then proceeded to capture 61 sample points covering one half of the sky, Grant Christie had advised me to do half the sky at a time to avoid mirror flop issues, so once this was done I then proceeded to capture sample points on the eastern side of the sky, unfortunately the first row of points was below the level of the dome so I just skipped these points, I had captured about 17 points on the eastern side when clouds put a stop to any further efforts, so I took a break and went outside to hang out with Allister who by this point was packing up his equipment, by the time Allister left the sky had cleared up again so I continued the automated calibration run but after just a few sample points the slewing of the telescope started making the same unhealthy noise that I had reported after doing my manual pointing model, knowing that the solution to this problem was clearing the pointing model and being happy that I could now easily do a new automated pointing model, I deleted the pointing model that I had spent all night capturing, I then re-homed the telescope and turned off the Paramount thinking that this would solve the problem but when I restarted the mount and gave it a test slew it was still making the same unhealthy noise, so again I re-homed the telescope turned off the mount and this time turned the Sky X off, I then took a good half an hour break before restarting the Sky X and the Paramount but again the mount was making the same unhealthy slewing noise, I'm starting to think the problem may not have had anything to do with the pointing model after all because this was happening with no pointing model at all, not wanting to cause any damage to the Paramount I just re-homed the mount and turned it off, the next clear night I will head out and try the automated calibration run again but if the mount is still making the unhealthy slewing noise I will have to just wait until someone can come out and take a look at it as I have no idea why it would still be making this unhealthy noise when there is no pointing model, heading home I was elated that I had finally figured out how to do the T -Point automated calibration run but this feeling was tempered by the concern I have for the unhealthy slewing noise the mount was making, hopefully it's nothing too serious.


^ T - Point sample plot screen shot.


^ Allister's giant binocular Dobsonian ( built by David Moorhouse )

Posted by Jonathan Green

Wednesday, February 3, 2016

Automation Frustration

We had a clear night out at Kumeu last night, so I went out there with the plan of doing the automated T- point calibration, after taking a few images manually with the Sky X and astrometrically solving the images via the image link feature, I started an automated calibration run, I quickly became frustrated though as none of the automated images would solve, I found this to be inexplicable as I could pause the calibration run, right click on an image that was captured via the automated calibration run and open it up in the image link feature and successfully solve the same image that failed to solve during the calibration run, it wasn't like it was taking a long time to solve the image either, so after trying this more than a few times, I then decided I would just slew to each mapping point of the calibration run, take an image and manually solve each image, this would work up to at most 11 sample points but then after that I couldn't solve anymore images, it was like the image link would just start to fail to recognise the stars anymore even though to my eye the images looked the same from start to finish, I remember Grant Christie telling me that you could run into problems if the temperature compensating focuser (TCF) wasn't correctly tracking the temperature, I was controlling the TCF using Maxim DL as the Sky X still can't connect to the TCF since we had the power cut that I reported a few weeks back, so this might be the issue, although I'm really unsure about it, I did have the temperature tracking turned on in Maxim DL and I was watching the TCF and I could see it was making adjustments over the night so I really am quite perplexed, after attempting different exposure lengths and different binning modes without any luck, I really felt at a loss to why the images captured during the automated calibration run wouldn't astrometrically solve, maybe I need to adjust the detection threshold in the image link or something? I kept at it until 4 am in the morning becoming even more frustrated as the hours went by, clouds rolled in around 4 am putting an end to my efforts so I closed down the dome and called it a night heading home in frustration, I think I'm going to need some help with this as I re-read the T-Point manual today and could find nothing that would help me resolve the problem, hopefully once we get the TCF working with the Sky X again this will help although I'm still at a loss to explain why none of the automated calibration images would astrometrically solve.

Posted by Jonathan Green

Monday, January 25, 2016

Slewing Problem Resolved

I rang Grant Christie today to let him know about the unhealthy noise the mount has been making when slewing, he let me know that the problem was probably due to me having to home the scope during the T - Point calibration run, apparently doing so changes two of the parameters of the pointing model and can cause problems, so I went out to Kumeu tonight to clear the pointing model to see if this would fix the slewing problem and I'm very happy to report that the slewing of the mount is now back to sounding healthy again, I also finally figured out how to connect the CCD to the Sky X, the reason I was getting error messages was that you can't have the camera connected to Maxim DL and the Sky X at the same time, up until now the first thing I used to do when I arrived at the observatory was to connect the camera to Maxim DL so I can turn on the camera's coolers as it takes a while for the camera to cool down, I know now this was the reason why I was getting no response from the camera when attempting to connect to it through the Sky X, I'm feeling a little bit sheepish that it took me so long to figure this out but I guess it's all part of the learning process to have a bit of trial and error.

Unfortunately the sky was pretty cloudy out at Kumeu tonight, I did take a few images using the Sky X to control the CCD but I failed to astrometrically solve the images, this was probably due to the images being affected by clouds, hopefully the next time it's clear I will be able to do a new pointing model using an automated calibration run, I plan to take two to three hundred samples of the sky so we will end up with a very robust pointing model, I stayed out at Kumeu until 10:30 but the sky seemed to be getting worse and with the internet not working ( another problem that needs to be addressed soon ) I had no way to know if it was worth waiting around to see if it would clear up, so heading home a bit frustrated that I couldn't get more done tonight I had to console myself that at least when the next opportunity presents itself the telescope and mount are ready for action again.

Posted by Jonathan Green

Sunday, January 24, 2016

New T - Point and Slewing Problem with the Paramount

On Friday night I spent the entire night working on making a new pointing model, I scrapped the last one after reading the T - Point user manual and finding out that it was not advisable to take samples down near the horizon due to atmospheric refraction that causes offsets between the actual position of an object and it's observed position, I started collecting samples around 9:30 and only stopped collecting samples early in the morning due to the mount making an inexplicably unhealthy noise when it was slewing, I couldn't see any obvious reason why the mount was suddenly making the noise ( sounds like a rattle with clicking or cracking type noises ) so I just put the mount back in the home position and called it a night, by the time this had happened I had collected 82 sample points, the new model showed that we are only off by 2 arc-minutes in azimuth while the altitude was still excellent and we don't need any more adjustments in that area.

After attending the Auckland Astronomical Society council meeting at Andrew's house on Saturday, I thought I'd head out to Kumeu and see if the Slewing was still making that same noise and to also test the new pointing model, The first ten or so slews sounded healthy but then again inexplicably the unhealthy noise started up again, so again I just put the mount back into the home position and called it a night, I've talked to Steve about the problem and he is at a loss to explain it as well so we might need Grant Christie or Tim Natusch to come out and take a look at it, hopefully it's nothing too serious, before this happened I was quite happy with the accuracy of the new pointing model, objects were always just a few arc-seconds from the center of the frame although I didn't get a chance to slew all over the sky so some areas may be worse than others, I still had the same problem with the mount in the area of sky to the South East that I had the first time I attempted a pointing model so I couldn't take samples around Centaurus, Crux or Carina, below is an example image of the Galaxy NGC 1532, the image was a 100 sec long exposure and I was quite happy with how close the galaxy was to the center of the frame, the image exhibits some pretty bad vignetting but I think this was due to the Moon being almost full and very bright.


Posted by Jonathan Green

Wednesday, January 20, 2016

T - Point

Last night the waxing gibbous Moon was up and more than a few clouds were about as well but seeing that there were plenty of large gaps in the clouds I thought it would be a perfect night to get the new pointing model done using T - Point, when I arrived at the observatory I noticed that the computer was off and the temperature compensating focuser was flashing, I'm guessing that there was a power cut during the storm we had earlier on in the week, I booted up the computer and connected to both the telescope and camera without issue but when I tried to connect to the focuser it would not connect and came back with an error message from both Maxim DL and the Sky X, after ringing steve for help I switched the focuser back to manual mode and manually set the focuser back to the last known good focus, this worked well enough for me to be able to do the pointing model, the next issue was aligning the finder scope again which must have been knocked fairly far out of alignment at some point, this took me a while to get right but once I was happy that the finder scope and the field of view of the CCD were aligned again I got started on the pointing model, at first I had wanted to do an automatic calibration run but unfortunately the Sky X would not connect to the camera and I got error messages, I also noticed that it will be quite hard to keep up with an automated calibration due to the dome being fairly slow, not wanting to waste a good opportunity to get a pointing model done, I set about doing a manual pointing model using stars that I knew and that I could confirm through the finder scope, by the time the clouds really rolled in at 2:30 am, I had captured 57 samples, one problem I noticed when I was capturing the samples was that I couldn't take any samples from around Carina and Crux any attempt to jog the telescope in this area of the sky caused the mount to become confused and try to point the telescope at the floor, each time this happened I had to re-home the telescope before it would accurately point and track again.

The new pointing model confirmed that the altitude of the mount is correct but that the azimuth still needed to be adjusted ( by about 3 arc minutes ), I then enabled the Pro Track so that the new pointing model can make minor adjustments to improve the sidereal tracking rate of the Paramount GT - 1100S, at this stage the clouds had become so thick that trying to test the new pointing model's accuracy was pointless, so at 3:30 am I closed up the dome and called it a night, I'm looking forward to the next clear night when we can test out the adjusted tracking rate and also the accuracy of the new pointing model.

Posted by Jonathan Green

Tuesday, January 19, 2016

Polar Alignment Refined & Observations of Arp 123 & Arp 279

Last week we had a one good clear night and few nights with sporadic clouds, Thuesday night was the one clear night and on that night I took images of two pairs of galaxies that are in the catalog of interacting galaxies of Dr. Halton C Arp, one pair was NGC 1253 & NGC 1253A, collectively known as ARP 279 they are located in the constellation Eridanus and are thought to be lie around 75 million light years away, the other pair is NGC 1888 & NGC 1889 which are collectively known as Arp 123, they can be found in the constellation Lepus, after doing some research I've found that NGC 1888 is thought to lie 33.5 megaparsecs away which is over 109 million light years! for now this is the most distant object I have ever imaged, I'm looking forward to breaking that record soon hopefully, the image below is of Arp 123, image data was captured by Jonathan Green and then processed by Amit Kamble.


On the Thursday I also collected more image data on Arp 279 but not long after the Moon set clouds started to roll in, there were still gaps in the clouds so I attempted to image a couple of comets, I imaged both 81P/Wild and 203P/Linear but finding them took some effort, I realised after finding the 1st comet that our pointing model was off by about 13 arc minutes, this was due to our refinement of the polar alignment on a previous night.

On the Friday night the sky looked nice and clear and the satellite image data also looked promising so I rang Steve to see if he was free to head out to Kumeu to work on the Polar alignment and to create a new pointing model with T-Point, we also had a couple of Auckland Astronomical Society members show up with their Dobsonian telescopes looking to take advantage of the clear skies, unfortunately the clear skies did not last long so the nights observing was a bit of a bust, fortunately we could still detect stars through the cloud so we ended up spending the night until 2 am in the morning refining the polar alignment again, now all we need is some clear skies to do a new pointing model.


Posted by Jonathan Green



Saturday, January 2, 2016

Rain, rain and more rain....

After some wonderful days and nights between Christmas and New Year, (when, of course I was away from Auckland!), the rain has been falling pretty much non-stop - not to great for observing, but a perfect opportunity to get a few things done that have been on the list for a while. First order of business was getting the USB interface board for the dome rotation system. This has up to now been screwed to the wall inside the dome, but with the issue being unprotcted and that its location was right below the dome home position.  Whilst we've been working, a number of times we've opened the dome and has mosture drip perilously close to the board.  Installing the plastic enclosure took a little longer than expected, but the board should now be protected from and water or moisture from above and be a little more immune to spiders and dust. 
 With that complete, next step was to install the new red LED strip lighting around the dome.  The old dome lighting was too dim with the red bulbs in when working in the dome, and inconvenient to adjust brightness or turn on/off (as the switch is downstairs).  We switched out the bulbs for white bulbs making it easier when we are working (not imaging!) but also bought some red LED lighting with an RF remote to adjust brightness and/or turn on and off. The new lighting is much more controllable and convenient, and hopefully makes life much easier whilst imaging in the dome.  
The final job for the day was re-wiring the dew heater to the new power supply.  At the same time, i added in a PWM controller to control the temperature, ironically one actually designed to dim LED lighting strips.    A good productive day, even though the rain continued relentlessly. The only challenge at this point seems to be that Azimuth sensor for the dome rotation doesn't seem to be functional  (before and after the board was remounted, so not the loose wire I was hoping for) this could be a configuration issue rather than a hardware fault (the dome home sensor is working fine proving the interface inputs are working) but this will need more work
 
 

Time Zone

All times on this page are in New Zealand Daylight Time in winter GMT +12 or summer GMT +13.