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is that it's not a hardware issue but has something to do with the Sky X, Steve noted that our version of the Sky X was out of date so maybe by reinstalling the latest version of the Sky we might be able to resolve the issue, the evidence for the Sky X being the problem has been mounting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

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