I played around with it a little bit. I attached a sample Arduino program with dew control inputs/outputs and a function added to your program. I probably didn't integrate it perfectly as I have never written anything for ASCOM before, but its a starting point. Added a DHT22 sensor (ambient conditions) to pin 8, PWM 12v MOSFET heater control to pin 3, and a DS18B20 temp sensor (for the heating element behind the flat panel for PWM control) to pin 4.
I'm working on a flip/flat panel for my AT130EDX prior to it's arrival, based on your design. I'm looking at adding a dew heater to the panel, similar to what DeepSkyDad and Wanderer Astro have been adding to their latest models. It seems like it should be pretty easy to add, using the already available 12V power and a PWM pin from the Arduino Nano. Using something like this from Amazon behind the EL panel: https://www.amazon.com/dp/B07JVPV2SL/ref=sspa_dk_detail_0?psc=1&pd_rd_i=B07JVPV2SL&pd_rd_w=cUKPE&content-id=amzn1.sym.8c2f9165-8e93-42a1-8313-73d3809141a2&pf_rd_p=8c2f9165-8e93-42a1-8313-73d3809141a2&pf_rd_r=N377R6D4CT69FYSMZ7WA&pd_rd_wg=nugIo&pd_rd_r=d5ffded6-9002-47d7-b023-f26b6db8c883&s=musical-instruments&sp_csd=d2lkZ2V0TmFtZT1zcF9kZXRhaWw...