9 April 2021 Imaging Session – Joshua Tree National Park

Date:	April 9-10, 2021
Location:	Cottonwood Spring, Joshua Tree Natio26nal Park
Observing Time:	20:00 – 4:00 (UTC -7)
Weather:	Clear w/ distant high clouds, calm, hazy, Seeing – 2/5
Temperature:	80°- 60° F (26° – 15° C)
Bortle Scale:	3

Object	Constellation	Frames Layered	Combined Exposure
Antares	Scorpius	3	18 min
M4	Scorpius	8	27 min
NGC 6231 (C76)	Scorpius	4	18 min
M3	Canes Venatici	2	12 min
M13	Hercules	5	21 min
M64	Coma Berenices	6	26 min
M100	Coma Berenices	4	24 min
Milky Way		2	5 min

Object	Constellation	Frames Layered	Combined Exposure
Antares	Scorpius	3	18 min
M4	Scorpius	8	27 min
NGC 6231 (C76)	Scorpius	4	18 min
M3	Canes Venatici	2	12 min
M13	Hercules	5	21 min
M64	Coma Berenices	6	26 min
M100	Coma Berenices	4	24 min
Milky Way		2	5 min

Notes:

The only good image I was able to take on April 2!

I had gone out the previous Friday, April 2-3, and tried getting a few images before the waning gibbous moon ended the session shortly after 1:00 local time. But unfortunately, the images taken that night were not up to my standards – too many issues with guiding, and the background stars were not looking good.

I noticed the lighting on this rock formation, and took the shot with just my regular lens.

While calibrating my finder to what the main telescope saw on a distant hill, I saw these vultures on the rocks and of course snapped the shot.

Before I went back out on April 9, I found that the mirrors were way off collomation, which was due to both of them being too loose. I made sure this time on the night before, and before it got dark that they were collomated and secure, as well as being very vigilant on how balanced the setup – an Atlas II mount being a belt drive needs perfect level balance, and I didn’t make sure of that the last time.

While there was still some coma issues which I’ll have to figure out (yes I have a coma corrector!), overall, the exposures and the images from this night were much more to my standards!

One funny thing that happened is while using PHD2 for setting up the autoguider, it kept failing to calibrate, citing “no RA movement detected.” After several more attempts, I made sure the setup was perfectly balanced – it was. Then I made sure the mount was polar aligned enough – it was. But just before I tried calibrating again, I noticed the error – I forgot to connect the cable from the camera to the mount! Oops!

I’m very happy with the shots of M4 and Antares, and even more proud of being able to stitch the two together into a mosaic due to the cluster being just over a degree away from the red supergiant. Perhaps I didn’t need to make it as red as I did in the solo shot.

The two Milky Way shots are done through different methods – one a tracking shot, the other a non tracking.

With the non tracking shot, in perfect timing, a car coming up the road was shining its lights and lighting up the landscape, and I figured I could take advantage of the lighting. Sure enough it added a lot of character to the shot!