Back to forums

"GAIN" setting on ASI585 MC PRO

ZWO ASI585MC Pro CMOS Acquisition
7 replies•354 views
Pol Marchal avatar
Pol Marchal avatar
Hello,

I just bought a ZWO ASI 585 MC PRO camera which replaces my CANON EOS250D camera.

I took my first photos yesterday evening with this camera, the sky was pretty good, the Moon not yet up…

I set the GAIN to 252, as recommended by the ZWO instructions. To my great surprise the photo was overexposed.

I see on ASTROBIN very nice photos with this camera and the same telescope as me (150/750 PDS SW).

Do you have any advice on setting the GAIN? The goal is to have an exposure time of 5 minutes per photo. I am also interested in your advice for the GAIN settings on the BIAS and DARK.

Thank you in advance.
Well Written Respectful Engaging
Armin Lukas avatar
Armin Lukas avatar
How is the light pollution at your site?
5 min sub length seems a bit high to me. Try 120-180 seconds.
The gain settings for darks and bias should be the same.
Concise
Pol Marchal avatar
Pol Marchal avatar
Thank you for your reply. I don't know this information, but I was already doing 300 seconds with my camera and it was going very well.
Armin Lukas avatar
Armin Lukas avatar
It also depends on your target. Galaxies with a bright core should be exposed much shorter. I would say like 30-60 sec.
Tony Gondola avatar
Tony Gondola avatar
I agree with all of the above. You didn't say anything about what you are imaging or imaging with and how much light pollution you have but in general, five minuets is a long exposure and really is not needed with modern CMOS cameras. You are using the right gain setting to get the lowest read noise, you just need to shoot much shorter subs as pointed out above.
Pol Marchal avatar
Pol Marchal avatar
The targets are nebulas or galaxies. In this case I was talk cygne nebula.

The light pollution in my area is 21 to 21,5 mag/arcsec2.

So, I will try down my exposition time to keep gain = 252.

Thanks !
Thomas Groh avatar
Thomas Groh avatar
Hi,

I did my first steps with this cam. I love it. I used gain 252, because it was not clear, that 252 the can recognise the step down.
Maybe it is paranoid. Well I never had overexposed images. I can not imagine how this could be in the night sky. Maybe in dawn.
Look my first image here was M31 with your gain:

https://www.astrobin.com/3py14s/?nc=&nce=

CS

Thomas
Pol Marchal avatar
Pol Marchal avatar
Your M31 is very nice ! Thank you for your comment.

Good Sky !