Wednesday, September 20, 2017
Last night we also had a few visitors to the Observatory we had a local Kumeu astrophotographer who is just 16 years old come and take a small tour of the Observatory with his Dad, we encouraged them to join the society and to visit Stardome where they will be able to actually "look" through a telescope, we also had two society members use the observatory grounds as a dark site to do some deep sky astrophotography from, so it was a busy night out at the observatory indeed! Even though it was really a very frustrating night for myself.
<- Robert Patterson setting up his imaging rig
Posted by Jonathan Green
Monday, August 28, 2017
Speaking about derelict, Jonathan Green also met up with the treasurer of the society Niven Brown on Sunday afternoon to show him the damage to the dome that Steve Hennerley had discovered before he went overseas, basically we have a bit of rot on one side of the dome, probably because the skirting was never replaced and is inadequate to protect the under side of the dome from the elements, David Moorhouse had mentioned this problem to Bill Thomas last time he saw him in the city, Niven took some photos of the damage and will circulate them to the council, so hopefully with the consent of the council we will be able to hire a builder to come fix the problem, we also want to get the dome cleaned up as well seeing as it looks quite grubby with loads of moss and mold on the outside of the dome, it will probably need treating with a chemical wash and perhaps could be re-painted afterwards as well.
< Screen shot of an image of the Trifid Nebula that I'm working on in PixInsight, I'm still learning how to use PixInsight but it's a fantastic program and I can really see why Rolf Wahl Olsen gets such great results using it.
Posted by Jonathan Green
Saturday, August 5, 2017
Another issue that has been discovered with the amount use of the dome is now getting is that the fibreglass sides are starting to really degrade and will require some maintenance, we will be bringing this up at the next society council meeting to hopefully devise a plan of action to repair the dome and perhaps even get the dome cleaned and painted at the same time as it's quite grubby after all these years.
<- M8 The Lagoon nebula captured and processed by Shaun Fletcher at Kumeu Observatory.
Posted by Jonathan Green
Friday, July 21, 2017
Even the IT support favourite advice of "turn it off and turn it on again" (well unplug it completely) did not manage to solve the issue. Unable to contact Steve initially, Jonathan headed out to make the most of the clear skies with some DSLR astrophotography.
The following night Jonathan and Steve managed to hurry along the Auckland Astronomical Society council meeting members with a view to getting out of the meeting and up to the observatory as quickly as possible - with a spare computer power supply in hand.
Almost as expected (remember Murphy?).. the PC powered up instantly...
The challenge was working out WHY the PC had failed because having unreliable equipment is certainly going to have a negative effect on our efforts. Out came the power supply tester (Steve's a professional IT nerd so has these things lying around...) and everything looked good... fearing the worst... the "intermittent problem"... Steve reconnected everything and powered up again to start some additional diagnostics.
One common cause in the PC world when something goes off suddenly and won't power back up (even with a "power cycle") - but then does some time later (maybe many minutes later) - is that there has been a short circuit, power surge or "overcurrent" problem somewhere on the motherboard or power supply. Most IT techs have seen this most often when an errant screw accidentally makes its way (purely by itself you understand) onto the exposed boards of a PC. The protection circuity (such as polyfuses) kick in and power is removed. It is common not to instantly come back on when the fault is removed.
The hunt was on - for insects in the power supply, "errant screws", possibilities of electrical surge (though the surge protector was still functioning). Nothing was obvious ... so case back on and stand the PC back up.
At that point the probably cause of the issue was suddenly staring us in the face... the bright blue power LED (which is normally covered loosely with black electrical tape) was off... whilst the PC was on. Jonathan was certain the light was on the night before when he was setting up and checking inside again, it was still connected.
It seems likely that the blue LED had failed, which in turn had tripped protective circuitry on either the motherboard or the power supply. The mystery solved, we could be a lot more confident it wasn't going to happen again, and we took the opportunity to do something that should have been done when Steve built the PC - disconnect the Hard Disk and power lights completely to protect the darkness of the dome.
|Light Curve from OB171186|
Posted by Steve Hennerley
Monday, July 17, 2017
On Sunday the 16th of July we finally had a new microlensing alert so it was action stations! Only one problem the forecast for that night was for increasing clouds! We decided to give it a go anyway and just hope for the best, Steve arrived 1st and found the sky was half clear and thankfully our target was on the clear side, so he opened up the dome and got to work, he captured 14 300 second exposures of our target OB171317 before Jonathan arrived, after a few cloudy patches we got back to work but it was slow going with passing clouds causing our guide star to fade more often than not, Steve headed home and Jonathan stayed on to keep imaging for as long as possible, we got to 27 300 second exposures of our target OB171317 although thin clouds may have affected a few of them.
Posted by Jonathan Green
Tuesday, July 11, 2017
^ As you can see from this image of the cloud sensor graph clear patches have been few and far between, it's been frustrating because other parts of Auckland have looked relatively clear.
Posted by Jonathan Green
Tuesday, July 4, 2017
Obviously there has been a lot of rain over the weekend and things are starting to get a bit more muddy outside the observatory, it was really wet on the night as well with the humidity at a 93% level, Jonathan was very happy to see that at the end of the night we didn't have any sign of dew on our corrector plate so he thinks that the dew shield has proven to be the only thing we really need to keep the dew off, this is just as well because when you have to run the dew strap heater this adversely effects the images.
^Looking down the dew shield at a clean corrector plate after a nights observing in 93% humidity, note also how well baffled the dew shield is, David Moorhouse really did a fantastic job constructing this dew shield!
Posted by Jonathan Green
Saturday, July 1, 2017
After preforming the meridian flip we changed targets to OGLE-2017-BLG-1161 as Grant had mentioned that this was the priority target, we ended up getting 34 x 500 second exposures of this target before it got into the fog and mist of the western horizon, we got 32 x 500 second exposures of the OGLE-2017-BLG-1135 target and we also managed to grab 8 x 500 second exposures of OGLE-2017-BLG-0019, one thing I noticed over the night was that some images would not automatically solve in PinPoint so I think we might need to adjust our settings in PinPoint when solving images in the bulge, by 5am I was losing my guide star due to the mist and clouds that were hanging around low in the West, so this was a natural stopping point for the nights imaging. I calibrated all our data and copied it onto a USB data stick, shut down the dome and headed home around 5:30am, when I got home I immediately copied the data onto my computer and sent the files to Steve via the We-Transfer file transfer service, all in all it was a very productive night and I was happy to see when I woke up an e-mail from Grant saying that he had no problem running our images of OGLE-2017-BLG-1161 through Pysis and that the photometry looked good, we are now looking forward to the next clear night so that we can capture the normalisation data for our new targets.
<- The Galactic Bulge not long before Jonathan stopped for the night, thin clouds and fog made auto-guiding impossible and with not being able to auto-guide he couldn't continue capturing 300 second exposures anymore, so this became a natural stopping point.
Posted By Jonathan Green
Wednesday, June 28, 2017
|The Sky conditions looking towards the Galactic bulge for the 1st half of the night.|
Posted by Jonathan Green
Tuesday, June 27, 2017
^ Jonathan Green Shows a member of the public Jupiter through his 8' Meade LX90 SCT.
On the 26th of June Jonathan Green headed out to Kumeu Observatory at 7 pm in the hope of finally capturing some clear skies unfortunately the sky was completely clouded out when he arrived, the forecast was for a clear skies for the following day so in the hope the skies would clear sometime over the night he setup the newly cleaned dew shield onto the "Nustrini" C14 and opened up the dome, while waiting Alan Kane turned up also with the idea of doing some observing, I talked to Alan about the cloud sensor and how it was no longer logging data on the graph and he showed me how to reset it, so our cloud sensor is back to working properly again which I'm really happy about, by the time Alan had set up his Dobsonian the sky started to have a few gaps in the clouds, so I set about gaining focus, after many attempts the best I could manage was a FWHM of 2.5 arc seconds per pixel, not good at all compared to the other night, Alan also confirmed that the seeing looked average visually.
The clouds were coming and going so I attempted to get some work done in the odd gaps, what I wanted to do was take an hour or two of normalising data on the previous microlensing target that we got data on the last time it was clear, because you can't submit your data without the normalising data, I did manage to capture an hours worth of data but I was really not happy with the quality of the images even though I didn't have the dew strap on at all thanks to using the dew shield, using the graph window in MaxIm DL I could also see that the results were really jumping around, I went outside to talk to Alan about the sky conditions and he confirmed that even in the clear gaps we were still getting mist and thin clouds so this was no doubt what was causing the results to jump around, around 11 pm I had to stop due to deteriorating conditions, I went to calibrate all the data I had captured on the night so far only to find I had made a rookie mistake, all the data I had captured on the night was at 2x2 binning but we only have full calibration files for 1x1 binning, I guess my mind was a bit distracted as my e-mail accounts had been hacked that day and I was still getting phone calls about it while I was at the observatory, I just didn't notice that the binning was at 2x2 not 1x1, it was a painful lesson to learn as it meant the nights observations were useless but I know I won't be making that mistake again ( I hope ), on a positive note the dew shield worked perfectly, so I think we will be keeping that on the telescope from now on, by 11:30 pm the sky conditions had really become quite bad so Alan packed up and headed home, while Alan was packing up I managed to focus a star at a FWHM of 1.7 arc seconds per pixel during a break in the clouds, so not wanting to go home while I had a finally managed to get a half decent focus I stayed on, unfortunately the sky conditions just worsened so I ended up giving up around 2 am and packed down and headed home in defeat, hopefully the sky will be clear tonight so I can finally get the normalising data I need to start submitting microlensing data.
^ David Moorhouse's well constructed dew shield on the "Nustrini" C14
Posted by Jonathan Green
Monday, June 19, 2017
<- The Sharpest Focus ever recorded at Kumeu Observatory so far!
I noticed that the one part of the Sky that seemed not to have many clouds, was looking in the direction of the constellation of Carina, so knowing that there is an interesting target in that part of the sky, I set about gaining focus, It was a bit strange that on a night when the conditions were so marginal I managed to get the sharpest focus ever obtained from Kumeu Observatory! With a FWHM of 1.25 arc seconds per pixel on a Mag 8.6 star! We have discovered evidence that we have mirror flop issues so maybe the mirror just flopped into perfect collimation or something?
After gaining a sharp focus I started to image the Star Cluster Westerlund 2, the cluster contains some of the most massive stars known in our galaxy as well as many interesting "Wolf–Rayet stars", even though that part of the sky was the clearest, I think there was still enough clouds around to end up effecting the images so I'm not sure if the data will be useful or not but Grant Christie and Tim Natusch at Stardome Observatory have been studying the cluster for a while now so they might find the data useful.
^ A stack of an hours worth of one minute exposures of the Star Cluster Westerlund 2 in the constellation of Carina.
By the time I finished the hour long run on Westerlund 2 I set about attempting to gain some data on our current microlensing targets but needing to get five minute exposures I found I couldn't autoguide for long before losing the guide star due to clouds, so after a few attempts I went outside and found that the sky conditions had deteriorated, so I packing down and headed home just after midnight.
<- The Sky Conditions when I arrived at Kumeu Observatory.
Posted by Jonathan Green
Saturday, June 10, 2017
^ Dew on the inside of the corrector plate, it's looking like we will have to just work with the dew strap on or else risk not getting much done on clear nights.
Thursday was a lovely clear day so seeing my opportunity I headed out to Kumeu in the afternoon before sundown to grab sky flat's for calibration, while I was waiting for twilight I was visited by Steve Calveley and his wife, Steve owns the land that Kumeu Observatory is located on and he is also a past president of the Auckland Astronomical Society, I showed him all the new equipment in the dome and talked about our research projects, he was very happy to see Kumeu Observatory back in operation and shared some interesting stories about the observatory and the society from back when he was involved, he also expressed an interest in helping out with the current projects.
After Steve and his wife left I got on with capturing Sky flats, now that I have the flats for the "wratten filter" we can now reduce our image data correctly for submission, being there so early and with all our current targets very low in the sky I decided to have a go at doing a new pointing model using the T-Point add on for the Sky X, after a few failed attempts I figured out how to do it properly again and managed to get a decent pointing model, although I did have a few failed pointing samples near the almost full Moon, we could definitely see that there is an east / west bias that is indicative of mirror flop but at least we won't have to do star synchronization and solve images each night to be able to point the telescope accurately, hopefully it will stay reasonably accurate until we decide to change things again, while I was finishing my T-Point model Steve Hennerley showed up, so after looking at the results and having a chat we decided to get on with some image acquisition of the microlensing target "OGLE-2017-BLG-0019", we managed to grab 2 hours worth of data on this target as well as some new images of "OGLE_2017_BLG_0896", one of the best moments of the night came when me and Steve managed to identify the target star using the OGLE finder Chart.
After Steve left to catch some sleep before work, I stayed behind and kept on imaging but I noticed that the auto-guider started losing it's guide star, I managed to resolve the problem eventually by disconnecting the camera and then restarting MaxIm DL, I then re-enabled the auto-guider in the telescope setup section and this seemed to fix the problem, although when your taking 5 minute exposures and run into problems like this you can end up wasting a lot of time and when your tired from being up late a couple of nights you tend to make mistakes, so after finishing off the two hours worth of images of the "OGLE-2017-BLG-0019" target and creating copies of the images that I then calibrated, I ended up closing up the dome and copied all the images onto my USB stick and headed home around 5:30 am.
I'm really looking forward to the next clear night and hopefully we will soon be able to complete our next goal which is to start submitting our data for analysis.
Posted by Jonathan Green
Tuesday, June 6, 2017
After Steve left I solved a few images and then focused a mag 8.5 star to a FWHM of 1.499 arc seconds per pixel, I then went to the microlens field and astrometrically solved the field to confirm the position, I managed to get 17 five minute exposures before the sky crapped out with fog and clouds, I left the observatory around 5:30 am as there was pretty much no chance to get dawn flats due to the bad conditions so we still can't reduce our data until we get new flats.
<- Focus Star
The above image is of the target microlens star field, please note that the image is not calibrated and was taken while the waxing gibbous Moon was still well above the horizon, even though I managed to get a decent focus I was forced to run the dew strap at full to keep dew off the corrector plate which would have no doubt affected the images, also something else I noticed was that the aberrations all look worse on the left hand side of the image but I'm not really sure if that's our collimation or the focal reducer causing that.
^ The current observing conditions have been very sporadic out at Kumeu, as you can see from this cloud sensor graph above, the blue parts are rain, the red parts are heavy clouds, the yellow parts are light clouds and or fog and the white parts are clear skies, so you really need to be on your toes to be able to get anything done, hopefully we will have more stable conditions soon.
^ The very picturesque scene looking at the valley across the road from Kumeu observatory, you can see that the fog and mist fills up the low lands but it's like the fog is like water in a bath and eventually it fills up the valley until it spills over and ends up over the trees and dome of Kumeu Observatory, it seems like this phenomenon might be quite a common occurrence at this time of year out at Kumeu.
Posted by Jonathan Green
Thursday, June 1, 2017
Before Alan had turned up I had opened up the dome, pointed the telescope to near the zenith and started to attempt to gain a good focus using the auto-focus function in MaxIm DL but I couldn't manage to get anything better than a FWHM of 2.3 arc seconds per pixel, I had already wasted around half an hour trying to get a better focus but I was kind of in a rush because I really wanted to go after a Star Cluster that Grant Christie and Tim Natusch have been currently studying over at Stardome Observatory, the time constraint was because the Star Cluster is in the Constellation of Carina and at this time of the year Carina quickly goes behind the trees so it's hidden from our view for most of the night as seen from the Kumeu Observatory dome.
So in the end I had to just settle for a less than perfect focus, finding the Star Cluster which is named "Westerlund 2" was fairly uncomplicated because all I had to do was enter the RA and DEC coordinates into the My Chart Elements feature of the Sky X, then centered the target and slewed to the object and it almost dead center on the first try, I then proceeded to image the cluster until it went behind the trees I managed to grab around 58 images, unfortunately these images couldn't be correctly reduced as we still haven't taken any sky flats for the "Wratten filter" which is the filter we should be using for all our scientific work from now on, I did fire off a couple of the images for Grant to take a look at for comparison purposes, I can now really appreciate how much work is needed to try get the "Nustrini" C14 as optimised as the 16' Meade LX200ACF that Grant and Tim use over at Stardome.
The Star Cluster Westerlund 2 in the constellation of Carina, this cluster contains some very interesting Wolf–Rayet stars. ^
One piece of news that I'm really happy to announce is that our frosting issues seem to be over for now. I think the desiccant obviously just need more time to remove moisture out of the imaging system, last night was a really good test as well because the weather station was recording the humidity at 91%!
While I was imaging the Westerlund 2 Star Cluster I was thinking about why I couldn't gain as good a focus as the last time I was out at the observatory, one thought was that maybe the collimation may have slipped out but it then dawned on me that I had made a rookie mistake, last time I was out at the observatory I had the dew strap cranked up to full and I had forgotten to turn it off, a quick trip up to the dome confirmed my suspicions, so I turned off the dew strap and waited for a few minutes while it cooled off before I again pointed the telescope to near the zenith to try gain a good focus, this time I managed to measure a magnitude 8 star at a FWHM of 1.4 arc seconds per pixel, so I think it must have been the dew strap that was mucking up my focus attempts earlier on in the night, so it has to be part of our shut down procedure from now on that you turn off the dew strap when closing up for the night.
I should note that about twenty minutes after getting a good focus I had to turn the dew strap back on as the corrector plate was starting to fog up, I had to wait for five minutes or so for the corrector to clear again but thankfully the focuser was tracking the temperature correctly so I didn't lose my sharp focus.
<- Two frame mosaic of the Cats Paw Nebula in Scorpius.
With all that behind me I set about imaging the Cats Paw Nebula I wanted to try making a mosaic of the entire nebula but only managed to grab two fields of view using 25 x 1 exposures each with the Optolong Red filter before the stars all started to fade, thinking that corrector plate had fogged up again I raced up to the dome but no the corrector plate was clear, I then ventured outside to see some of the thickest fog I have ever seen! In fact the fog was so impressive it even made this evenings News report. It was so thick you could barely even see any stars with the naked eye anymore, seeing that this was going to end my nights activities I closed up the dome and headed home around 4:30 am.
Posted by Jonathan Green
Friday, May 26, 2017
Halos around the stars after cooling down the CCD ^
The problem with the halos must have been in camera though because when I warmed up the camera the halos all went away and when I cooled down the camera they quickly came back, I had read online that after cooking the desiccant it may take a day or two for the desiccant to absorb all the moisture from the camera so maybe there just hasn't been enough time for the desiccant to do it's job or perhaps it's time to buy a new desiccant, we can't really do anything below zero degrees Celsius at the moment as you start to develop the halos below that temperature and once you have the halos they tend to effect being able to obtain good focus, I noticed that the weather station was reporting that the humidity was at 90% so I think this may have been a factor also, when I shut down the dome later on in the night the shutter was literally dripping wet! I also did some tests of running the camera at zero degrees Celsius for an hour or so and then cooling it down as me and Steve had read that in an online forum as being a possible solution to the problem but to no avail as soon as the camera was set to -20 you would see the halos start to form followed by frost in the 5-10 minutes after cool down, we will have to find a solution to our frosting issues quickly as the microlensing season is fast approaching.
Startrail looking south over the Wasp Observatory that I took while working in Kumeu Observatory. ^
I stuck it out until 2 am doing some pointing tests by astrometricaly solving images with the Image Link function in the Sky X, using this technique I could easily find variable stars such as AR Sco, so we will probably just use this method until we can get a really robust pointing model done, by 2 am the clouds had inevitably rolled in and put an end to the nights observations.
Posted by Jonathan Green.
Monday, May 22, 2017
|Cleaning the corrector plate on the C14|
|I'll get you....dust particles...|
|Dismantling the filter wheel on the SBIG ST10XME|
|Carefully cleaning the L filter|
We reattached the camera and cooled it down, only to be instantly frustrated by frosting again almost immediately. We are definitely going to "cook" the dessicant pack again, as it's clear there is obviously moisture in the system that's not being removed. We jumped on the internet (via Steve's phone as we've not get this sorted yet still) and learned a couple of interesting things about this problem:
- you can buy a replacement dessicant plug that takes disposable gel packs - this is fantastic as it would allow us to replace the dessicant quickly without the "cooking" process
- A technique described on a forum for cooling down in stages to avoid the frost.
After I left around 12:30, all Jonathan did was try image for a while but soon got hit with more frosting issues so frustrated, packed down and cleaned up the observatory including removing a dead mouse from under the dome ( gross but at least we know the rat bait is effective ), Jonathan ended up taking the desiccant home and cooked it (it goes in the oven for 4 hours to dry out the dessicant material) the next day. He then took it back out to Kumeu and reinstalled into the CCD camera, hopefully that should resolve our frosting issues for a while.
Sunday, May 21, 2017
|Dew on the inside of the corrector plate|
|CCD Inspectors's Single Star Collimation|
Starting off by identifying where on the image the collimation screws were in relation to the image (by making a shadow with my hand) it was easy to see which screw to adjust - basically the one which "moves" the image in the direction of the line on screen.
After making the corrections that CCD inspector gave us we improved the collimation then moved onto using the multi star collimation feature of CCD inspector, we used an open star cluster near the zenith but after a few attempts we ended up making the collimation worse so ended up having to star over !
|Steve Hennerley collimating the "Nustrini" C14.|
We ended up collimating the telescope until about almost 3 am in the morning, we could definitely see a huge improvement in the images and the shape of the stars, after Steve left Jonathan managed to focus a star near the zenith at a FWHM of 1.7 arc seconds per pixel, after taking a few test shots he could really see how improved the images were but we will need to monitor the situation because if the primary mirror is flopping we can expect the collimation to degrade fairly quickly, with another clear night tonight Jonathan and Steve plan to catch up again and see what else can be done in preparation for the forthcoming microlensing season.
Posted by Jonathan Green & Steve Hennerley.
Monday, May 8, 2017
I wasn't keen on a temporary fix (we all know how these have a habit of becoming permanent) - and a "dream" of mine since we installed the paramount was to get as much of the cabling as we could to use "through mount" cabling to eliminate the risky "cable snake" that carried signal and power to the scope equipment.
Indeed when we rebuilt the mount, we were already supplied with the standard SoftwareBisque connector panel - this was prewired with USB, a multipole pass thorugh power connector 5v and 12v outputs (though low current - we weren't too comfortable trying to drive the heater with the 12v). We worked out this was almost enough for us to connect everything we needed bar a couple of items - one of which was the dew heater.
|Custom wiring box on the mount dovetail plate|
in theory therefore, all that was required was making up a few cable connectors and we'd be to enjoy a cable-snake-less future.... Step one though is that we hadn't quite worked out the best (ie tidiest) way to get power into our extra power cables. There were a number of spare "keystone" type connectors in the mount side panel we could have used - but unfortunately the locking connectors we used at the scope side were too big to fit. We were originally planning to use "Anderson Power Pole" connectors but they didn't have an elegant panel mount solution.
|The mount control panel showing our|
newly installed Anderson PowerPole
connectors (top centre)
|How many parts?|
|Making the cable connectors|
Whilst it was a little nerve wracking to plug the new connector into the camera (even after double checking the polarity and voltage of the 3 voltage line pins), happily everything worked as it should have done and the camera spun up nicely. The only remaining piece of equipment to handle was our Optec TCF Focuser.
As luck would have it, this one was probably the easiest. The focuser connects to the controller by way of a 9 pin "D" plug cables to a modular RJ45 socket. As a career geek, I've always got a handful of RJ-45s and a crimper at hand, so this was a 2 minute chop the wire smaller and connect on a new plug (which was even cabled as standard "T-568-B Spec"). Adding a small Cat5 patch cord at the control panel end and suddenly a long time dream was just about reality!
All that remained was to tidy and tie up the wring to keep it need and free from snagging on anything and to double check all our connections, and - importantly - to make sure everything still worked..
The process of moving from externally cabled equipment to using a "through mount" approach has taken a lot of planning - even at the early stages when we were tearing out the old control gear from the mount. We needed to have our dovetail plate machined to take extra cables, and even create custom connector boxes. Even with everything in place there was a bit of research required for the final cabling and it took a good few hours just to get everything built and plugged in.
The end result though is that now, as well as a much neater set up, we are free from the worry of the cables dragging on the floor or snagging on something - or of course one of us tripping on it. We've also reduced the risk of damage to the cables, or a connector.
|The end result - notice that all the cabling to the OTA now goes to the dovetail palte connector boxes.|
NGC 2997 with the 1st signs of frost starting to form.(note that the image is uncalibrated and was also affected by the gibbous Moon.) ^
The Star that Nicola was monitoring went behind the trees so she packed up and headed home around 11 pm, after she left I started imaging part of the Lobster Nebula (NGC 6357), I captured around half an hours worth of data before the clouds started to arrive, I tried to wait them out but they were very consistent, it was very frustrating as I could tell the rest of Auckland was in the clear, the clouds were coming in from the west and not getting much further in before thinning out and dispersing, while I waited I got the vacuum cleaner out and gave the observatory a good clean up, after packing down I left the observatory around 2 am.
Part of the Lobster Nebula (NGC 6357) ^
I also went out to the observatory on Sunday night (7th) but got clouded out before I could get much done, I looked at the cloud sensor downstairs and noticed I had made the right decision leaving the previous night as the sensor showed that the sky didn't clear until 6 am!
Posted by Jonathan Green
Saturday, May 6, 2017
So we now have the bones of the Startup, Guiding and also "Point Telescope Here" documentation.
|Cats Paw - 40 mins exposure (2 min subs)|
It's not a particularly hard process to get working - in fact when we first did it we were surprised we had taken so long to get it working. It was so easy in fact that we didn't bother writing down what we'd done. Needless to say, it wasn't working in the new setup, and we couldn't quite remember the simple steps we needed to do!!
After requisite head scratching, it was indeed really easy to do - so I did it - but more importantly, I also wrote down how I did it so that next time it will be much faster!
Whilst working on this we also discovered the cause of the guiding woes from earlier in the week - it looks like it was just an extra "calibrate" that might have been needed to fix the problems! We had guiding working just fine in all the areas we tried.
Since Jonathan had enjoyed the remote operation experience so much, I also improved the monitor setup down in the bunkroom - there are now two bigger monitors to use which makes operation all that much easier.
The other major task completed tonight was another improvement on out polar alignment by doing a few more rounds of drift alignment. We have got rid of almost all the drift but still see more East/West movement than we are expecting - this possibly needs more investigation (could be just PE) but it's so slow that the autoguider will take care of it fully for now.
There was a little light cloud around so our test imaging wasn't particularly great and we are desperately in need of collimation. We have found out there is to be some microlensing work to complete next month so the race is now on to get these tasks - along with checking out the filters and focal reducer - knocked off before then.
Wednesday, May 3, 2017
The first thing I did was obtain focus using the TCF's auto-focus procedure this worked very well with a focus star giving me a result of a FWHM of 1.6 arc seconds per pixel, I then set about slewing to different objects and taking some test images but after a while I noticed that the TCF wasn't tracking the temperature changes so the focus had shifted off a bit, the temperature had dropped by about two degrees so when I went to run another autofocus I found that I could no longer obtain focus as the TCF wanted to go past 7000 steps when looking for the autofocus start position, knowing that the solution was to put the TCF back to the 3500 half way point and then manually get the focus back to as tight as I could by eye, I finally got back into focus although the focus Star I was now measuring was only giving me a result of a FWHM of 2.3 arc seconds per pixel, I don't know if that was because the "seeing" had changed or because having re-set the focus manually I had somehow changed the collimation.
- A stack of ten one minute exposures of the spiral galaxy NGC 5247, I think in this image the focus was already starting to go "Pear" shaped.
Imaging targets around the sky using the auto-guider I noticed that objects in the east couldn't be autoguided as the target stars were drifting off fairly rapidly, on the western side of the sky their was no problem at all so I think we really do need to do a lot more drift alignment to make sure we can autoguide on both sides of the sky, at this stage of the night I noticed the star shapes looked a bit funny ( not quite round ) I wondered if maybe the collimation had slipped out, but after a bit of investigation I found that we had dew forming on the inside of the corrector plate! I had encountered this the night before when hanging out with Grant Christie at Stardome while sitting in on his observations of a binary Wolf-Rayet star system, I knew that the solution was to crank up the dew strap to heat up the corrector plate but unfortunately our dew strap is not currently powered, I remembered Steve saying he had to think about how we are going to power it moving forward, so not wanting more dew to form on the inside of the corrector plate I shut down and headed home around 2:30 am, I've got to say I'm very thankful that Steve had setup the computer downstairs to control the dome computer remotely, so that I could operate in comfort, as on the way home I noticed my car's outside temperature sensor was recording the outside temperature at a chilly 3 degrees!
- Dew on the inside of the corrector plate.
So moving forward I think we have a number of tasks to prioritize before we can start doing some research grade observations, we obviously really need to get the dew strap powered! With the cold / damp weather here now it won't take long for dew to form on the corrector plate, we also really need to take the CCD off the mount and make sure the new filters are not moving, if the filters move even slightly we won't be able to do the data reduction correctly and with the microlensing season about to start we really need to make sure our data is reduced correctly for scientific submission and of course we really need to spend a full night or two doing the tedious task of drift alignment so that our autoguider won't have to work as hard and that autoguiding will work across the entire sky, all in all though we have made some great progress over the last few weeks so it's just a matter of building upon these successes.
Posted by Jonathan Green
- ► July (5)
- ► June (6)
- ► May (7)
- 3D NOAA Satellite Pictures
- Astrophotos from Kumeu
- Auckland Astronomical Society
- Chengho Han's Webpage
- Cloud Sensors
- Farmcove Observatory
- Kumeu Mobile WAP Weather
- Kumeu Weather Station
- Metservice NZ
- MicroFUN planet hunting
- MOA Microlensing Alerts
- OGLE Microlensing Alerts
- Paul Kemp's Observing
- RASNZ Monthly Competitions
- Ted Argos Focal Reducer Tube
- The giant 16" Binocular