70% or 80% Gain on Saturn? (ASI120MC-S)

[WilliamAstro]

Just a quick question should I use 80% or 70% gain on Saturn with my ASI120MC-S and 2x Barlow using FireCapture.

[WilliamAstro]

P.S. I use a Celestron Nexstar 127 SLT

[The Lazy Astronomer]

The general advice l follow for planetary imaging is to increase the gain to achieve low read noise and drop exposures to as low as possible. Looking at the read noise graph for the 120mc, there seems to be little benefit to using higher than about gain 65. Assuming gain 100 = 100%, then really it looks like it doesn't matter particularly whether you pick 70 or 80%.