Tuesday, June 27, 2017

Cloudy nights and a Rookie Mistake.

On the 25th of June Jonathan Green was involved in an astronomical outreach event at Smales Farm on the North shore, the event was a Matariki festival and members of the Auckland Astronomical Society provided telescope viewing to the public, we were ducking rain showers for most of the night but by 9 pm things had cleared up so sensing an opportunity I packed up and left the festival around 9:30 pm to head out to Kumeu, we have had a really bad run of weather lately so you really just have to take your chances when heading out to the observatory at the moment, the sky was still clear when I arrived but after I had opened up the dome and managed to get a decent focus heavy clouds began to roll in, I went outside and watched them for a while, the clouds became progressively thicker and the wind started to pick up, I was lucky to just beat a really heavy rain shower by racing up and closing the dome just in time, I attempted to wait out the clouds and rain by occupying myself with cleaning up the observatory and cleaning up the dew shield that David Moorhouse had built for the "Nustrini" C14, spiders had built lots of webs in it since we took it off when installing the Paramount GT100S, after I had done all that I found that it was still raining and with no gaps on the horizon I decided to head home around midnight.

^ 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

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