I'd been using the EL panel system for my flat frames for months. I taped the EL sheet to the rear of a 1/8 sheet of HIPS and attached to my observatory wall. For each filter I would slew to it and expose. This worked well but I noticed while slewing that I would lose focus as the OTA traveled and the mirror shifted/flopped. The 4 additional slews also complicated automation. All of this was manageable but enough of a hassle that I went seeking something better. I looked at the Flatman, but no automated product for a 14" scope, same was true for Aurora and the others.
I realized I would need to engineer something on my own. I tried many EL configurations to address these issues (reticulating arms, booms, lampshades, attaching it to the dome shutter) but all had tradeoffs and were less than perfect. In the end, a shaft/disk/stepper assembly worked the best and was the most stable.
Cost was about $600 all-in (I already had the Astrozap shield) which included the Arduino, stepper motor, stepper driver, shaft, pillow blocks, flanges, EL disk, EL inverter and the sheet of HIPS.
I figured I'd share as a flat alternative to those who are also looking for a fully automated solution for a big scope.
See it in action here:
Edited by jsowens, 12 December 2018 - 03:26 PM.