After the solar eclipse in April, it took me quite a while to get around to putting the observatory back to it’s normal nighttime viewing state. Unfortunately, then something went wrong with the serial interface between my controlling computer and the motor drive system that moves the roof, so I haven’t been able to open it for some time.
To top it off, the custom infrared remote control that would allow me to manually open the roof had it’s batteries leak and completely ruin the circuitry.
In order to get to the motor drive without crawling completely up into the roof framework, I needed to get that working again, so I eventually wrote some code on an Arduino Nano and replicated my command set to allow me to open and close the roof using the Arduino connected to a laptop.
I had to hotwire the old remote to let me generate a few codes just so I could confirm the timing and format, since it has been twenty years since I developed the original protocol!
Once I had that working, I decided it was finally time to do something I’d planned to do for a long time, and developed a web based interface on an ESP32-S3 embedded microcontroller with Wi-Fi. Now I can open the roof from any web browser on my network rather than having to remote into the one PC that was interfaced to the drive. Now I just need to write an ASCOM driver so that Sequence Generator Pro can control it directly.
Once I got the roll-off roof working again, I had to put my astrophotography rig back together. For the eclipse, I remembered that I had the 0.7x focal reducer for my C11, which worked great during the eclipse, so I want to try doing some imaging through that. About this time last year, I had developed a focus motor drive for my old Zhumell Crayford SCT focuser, but never really got the chance to test it properly.
I still have to use the SCT thread adapter to mount that focuser as opposed to the larger 3.3″ opening on the C11, but the focus motor works quite well, letting me lock down the mirror and eliminate mirror flop. I’d also bought a new small Askar off-axis guider to replace my old huge Taurus Tracker OAG. By the time I got the entire optical chain set up with the heavy focal reducer, focuser, and QHY-247C camera, things were WAY off balance. I had to add the final counterweight on the CGE Pro and shift the OTA way forward in the mount. Balance is great now though!
First light with the new setup (a month after the clouds rolled in the instant I got everything working and then ran through a full moon cycle), guiding is great, but the back focus is several centimeters too long and thus there’s quite a bit of field curvature around the edges of the field. The pick-off mirror of the OAG is also causing major vignetting in the side of the image. It needs to be rotated 90 degrees and shifted out as far as possible. I THINK I may be able to shorten the length enough to reach the 146 mm recommended by Celestron, but that remains to be seen.
This is a simple stretch of this first stack. I doubt I’ll finish processing this vs. trying to improve the setup and redoing it.
