This is my William Optics SpaceCat 51 f/4.9 imaging rig.

Originally the SpaceCat was purchased for use with my Fujifilm X-T100. The 14-bit APS-C size Sony sensor in this camera has exceptionally low noise with very little heat signature, and is significantly more sensitive to H-alpha than most other unmodified interchangeable lens cameras. However, the Fuji X-T100 had no option for a PC connection. Exposures are set within the camera. Exposures longer than 30" require the use of an external intervalometer with the camera in bulb mode. Also, in order to plate solve or check field flatness, files would have to be manually copied from the camera to the computer. Which often meant power cycling the camera, further slowing down and complicating the workflow.

Recently I added a QHY268C to my gear, allowing me to take deeper exposures of H-alpha emission targets with absolutely no amp glow and extremely low thermal noise when using the TEC system. Being able to build and reuse temperature dependent calibration libraries yields significant time savings, which also allows for longer imaging sessions.

The Celestron AVX mount is the foundation of this setup. It's more substantial than a simple sky tracker, but is still light and portable enough to take out in the field each night. It has been modified to make it easier to balance, but I've yet to reduce the guiding error to level that I'm satisfied with. Although, with a pixel scale >3"/px, any error the mount exhibits is still well hidden from sub exposures.

The stock 11.8lb counter weights of the AVX mount are too heavy for such a lightweight payload. A single 11.8lb weight can be used, but it sits so far up the counter weight bar that at lower latitudes you run the risk of the weight colliding with the altitude adjustment T-knob. Instead, I opted to use 3x iOptron 3lb counter weights. Which have the same bore diameter as the stock AVX counter weights. The smaller outer diameter of the weights provides plenty of clearance for the altitude adjustment T-knob and RA housing, while also providing more control over balancing with slightly reduced weight at 9lbs total.

For the guider, I'm using a William Optics UniGuide 32 f/3.75 guide scope with the Player One Mars-M (IMX290). Which pairs well with the SpaceCat 51 and both APS-C cameras at a pixel scale of 4.98"/px. The Mars-M has the same sensor found in the ASI290MM Mini, but I prefer using the Mars-M because there is no insertion stop on the UniGuide 32 to help consistently find focus after removing and reinserting the ASI290MM Mini. The nosepiece on the Mars-M provides the stop needed to easily and quickly find focus after having swapped the camera out for other uses. The ASI290MM Mini is now just used for OAG configurations.

For dew prevention, I'm using a pair of Protage USB lens warmers with this setup. They're easy to use, inexpensive, and just plug into a Sabrent 36W 7-Port USB3 powered hub with individual switches for each port. This allows me to power on these dew heaters during setup independently of the cameras and mount, which normally get switched on much later. The hub itself is strapped to one of the mount tripod legs with zip ties and uses Velcro backing to help anchor it. All cables are bundled together in a single wiring harness to help avoid cable snags. Since the power cable for the camera needs to be disconnected during teardown, that cable is strapped to the outside of the wiring harness using Velcro cable ties.

For flats, I'm using a wireless battery powered Huion LB4 LED light panel. One of the benefits of using a battery powered light pad is that even with short exposures you don't get the same banding issue you do when using a light pad powered by an AC adapter. It's lightweight, it operates under its own power, it's easy to stow, and is easy to control. I'm really happy with this model.