I had a couple of days away as a guest of the Orpington Astronomical Society at their Deep Sky Camp in darkest East Sussex with
@carastro and others. And a great couple of days it was too! The weather behaved itself, I even got sunburned. And the night time sky was just as clear as the BBC said it was going to be. High humidity was the only problem.
I arrived and set everything up, the new tent, still in the bag was supposed to be four man size but one sleeping bag laid diagonally worked out ok. After sorting out the electrical hook up I sorted out my new kettle and made a cup of tea. Then the tripod, CGX and
SCT came out of the car boot and I started the assembly process. I've been set up in the observatory for a while now and so had become out of practice with putting everything together. But the three small squares of OSB with a hole drilled in the centre worked to stop the tripod feet sinking into the ground. While getting the cables out and scratching my head my phone alarm went off to tell me that Solar noon was approaching. So I put a stick in the ground and lined the mount up with the shadow. If it was good enough for the ancient Greeks it's good enough for me!
Once everything was connected and switched on I fired up Stellarium, CPWI and
NINA on my cardboard and duct tape protected laptop. After homing the mount I imported the Sun's coordinates and slewed towards it. The polar alignment must have been quite close because after ramping up the exposure to two seconds the edge of the saturated Sun was in the corner of the screen. A stepped reduction of exposure and a few taps on the slew controls soon had the Sun in the centre of the screen. I zoomed in and got the best focus I could then switched to my new Continuum filter, adjusted the exposure and saved a loop of 30 seconds of exposures.
This is the result.
As the setting Sun dipped below the horizon that evening I fired up the
SCT again and waited for enough stars to appear to run the
NINA Auto focus and three point polar align routines. The mount was quite a bit out. I probably forgot to use BST or something. The ancient Greeks didn't have to put up with this poppycock!
The humidity was already at 99%! I thought there was something wrong with my sensor. But you could feel it in the air and I had the feeling that this was going to be a short session. First target was the list of Globular Clusters in this Month's
TSS Deep Sky Challenge. M3, M53,
NGC 5053,
NGC 4147 and
NGC 5466. With just a single 60 second exposure on each one I quickly compiled an excellent challenge submission. None of the images are high resolution astrophotography competition winners but having the craic finding each one, plate solving to the centre of the screen, capturing and moving on to the next was a lot of fun. All of them were of sufficient quality to appreciate their beauty.
Here's my submission. Think I'll do a Caldwell Challenge or complete the
TSS Messier Imaging Challenge next!
Then I wanted to capture a before the event T Corona Borealis nova image (as notified in the
Marshall's Weekly Events Post) in order to do a subsequent after the event image for comparison. So after a quick coordinates import from Stellarium,
NINA slewed the telescope round to T CrB and a plate solve nudged it to the centre of my laptop screen. Again, I just captured a few 60 second exposures. I will be checking the news for the nova ready to capture the after the event image.
This is the image.
After that I moved onto the main target I had planned, Abell 1656, the
Coma Galaxy Cluster in
Coma Berenices. I calibrated the guiding, slewed to the target, checked the focus and fired up a pre-prepared
NINA sequence. That soon settled into its thing so I went for a wander to see what others were doing.
My homemade Arduino rain sensor connects to
NINA through the Safety Monitor and it has a heater that prevents false positive detections that would be caused by condensation on the sensor plate. When rain is detected
NINA sends a notification to my phone and parks the telescope. The humidity had been at 99% for so long that the anti condensation measures failed! The rain sensor started bleeping, my phone started ringing and the telescope started slewing! I realised what was happening when it was clear that the sensor plate was wet but there was no rain.
I disconnected the rain sensor and fired up the sequence again with the if !IsSafe park telescope line deleted from the sequence but by now the guiding was deteriorating and struggling to stay below a total error of 1.0. The sequence aborts the exposure if the total error is above 1.5 for 5 PHD2 exposures in a row and most exposures were getting chucked! I don't know if the humidity was affecting my USB connections, my CGX motors or my polar alignment slipping off due to the soft ground but I shut the sequence down, disconnected everything, switched off and went to get my head down.
The next day was good, I lounged around relaxing, listening to astronomy and harmonica podcasts, chatting to the very nice OAS people and cooked some chilli egg fried rice for my dinner! As the Sun set we saw the two day old thin waxing crescent Moon on the western horizon. If I had been prepared I would have captured it but by now it was too low.
The second night was wholly allotted to capturing more data on the galaxy cluster. First step was to re-do the polar alignment, the OSB plates definitely looked like they had sunk a little into the soft field grass under the weight of the CGX. The
NINA polar align tool plugin reported 1.5° total error so I started a re-adjustment. The laptop screen was looking the other way from the position of the CGX AltAz adjustment knobs so I had to keep running round to the back of the mount to adjust then back to the laptop to check, all this took a while. After a few minutes the plugin told me I was taking a long time and I might want to start again! How rude!
The BBC weather said we could expect a lower humidity tonight so I set up the rig, changed the sequence to abort above 2.0 and changed the 9 volt supply to a 12 volt supply to the rain sensor heater to increase the temperature on the sensor plate if the dew point was close to the temperature. Then, once setup I fired up the sequence and went for a wander again. At midnight I set an alarm for 02:00 and went for a kip. At 02:00 the guiding was poor again and the exposures were aborting. So with a total of nearly five hours of exposures I went back to bed feeling quite pleased with myself.
An excellent Star Party and a big thank you from me to the OAS.
Right, I'm off to process some galaxy cluster subs.
Graeme
Member of the RASC