Yes, but, does your dsi-p have over a thousand hot pixels ? Mine does, and no amount of fussing with offset and/or gain changes that. A 1 minute exposure generates over a thousand pixels at full saturation.

I did find that in nebulosity there is a setting to turn off the amplifier, which I didn't see last winter, hiding in one of the camera config dialogs. I did tests here a couple days ago, and confirmed that with that set to amp off, the amplifier glow does indeed disappear from the corner of the frame, but, it doesn't solve the problem of hot pixels. There is a random scatter of hot pixels in every frame, they run roughly 95% reproduceable across frames, and there's more than a thousand of them. 3 minute frames the number approaches 2 thousand.

I think I've just got a lemon when it comes to the dsi-p.

But, that point does become academic, scooped up a used starlight express SVXH9 late last week. It was _supposed_ to be here on friday, but, turns out the priority courier folks decided to keep it in storage instead of delivering on friday. Chasing down the tracking, it appears to have been misplaced at one of the handling points, and didn't get on the outbound truck it should have been on, and is still sitting in that warehouse for the weekend.

it may not be the 'ideal' camera for this kind of stuff, but I expect it to be an order of magnitude superior to the dsi-p, and 'good enough' to allow us to attempt some of this fun stuff with the degree of precision we want.