Gain 0 for RGB stars - Forums

Topic starter

Mar 20, 2023

Hello everyone,

I am currently shooting Thor's Helmet in Ha and Oiii. I am planning in the next days to shoot some RGB data for the stars and I was wondering weather it is worth it to switch to gain 0 instead of 120. My camera is the asi294mmPro.
The point is to switch to gain 0 in order to maximize the well depth and help with oversaturation of the stars. Does this make any sense or it would be better to just reduce further the exposure time?

Thanks in advance and regards,
Devoll

Wim van Berlo

Mar 20, 2023

That makes sense. But if it’s only stars you want, you can just shoot at gain 120 and decrease the exposure time. You only need to avoid overexposing the stars.

jewzaam

Perfect post

Mar 20, 2023

Wim van Berlo:
That makes sense. But if it’s only stars you want, you can just shoot at gain 120 and decrease the exposure time. You only need to avoid overexposing the stars.

I agree, though I do shoot generally at gain=0 for LRGB for the well depth and longer exposure time which means I need fewer files for the same total integration time. I only switch to higher gain=100 (HCG) for LRGB when needing to shorten exposures, for example for the fast moving C/2022 E3 (ZTF) while guiding on stars.

Insightful

jewzaam

Perfect post

Mar 20, 2023

One thing to keep in mind when doing this is you need to take flats with the same read-out mode for the camera. I.e. I cannot use gain=0 flats for gain=100 lights and visa versa. But on my DSLR I can take flats at a lower ISO than I shoot lights which means I can expose longer.

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