First dedicated astro cam after several years of DSLR - advice please!

[AstroMuni]

43 minutes ago, edarter said:

I'm struggling to get hold of documentation at the moment, the altair website requires a login and that's not working for so.e reason. Being investigated apparently but does leave me a bit sparse on docs for this camera / chip combo. They have just sent me the latest software though while I wait.

The ZWO graphs are here https://www.firstlightoptics.com/zwo-cameras/zwo-asi-2600mc-pro-usb-30-cooled-colour-camera.html?_gl=1*1550dz8*_up*MQ..*_ga*NTI0ODU4NTE5LjE3MTE0NjU4NTQ.*_ga_F6VGWQ0MW9*MTcxMTQ2NTg1My4xLjAuMTcxMTQ2NTg1My4wLjAuMA..

As the 2600 also uses the Sony IMX571 its characteristics will be same as Altair's version. The main differences in camera would be primarily in the cooling circuitry and any USB controllers.

Here is a discussion on the various brands that use the same chip (albeit its talking about the mono version) https://www.cloudynights.com/topic/866522-what-is-the-real-difference-between-all-the-imx571-cameras/

Edited March 27 by AstroMuni

[edarter]

I've been doing some experimenting to try and find the right values for gain and offset, having watched a video done by Cuiv.  Sharpcap sensor analysis shows that gain 300 is where the S/N ratio drops so I understand that, though this translates to gain 150 in NINA with HGC enabled due to the way that Sharpcap calculates it for Altair TEC cooled cameras. Do the below figures look to be the right ballpark?

Cooled to -5 on the bench
Gain 150 with HGC mode enabled
Offset 260
Exposure is 0.0001 (is this to fast?)
Minimum pixel value is 6

 

Thanks
Ed

 

[PhilB61]

Very similar to what I use, cool to -5 , gain 100 and offset 250. After playing around with different exposure lengths I have settled on 120s for most targets occasionally 180s, although I don't use any filters. I think it's a good balance between getting sufficient signal and not losing frames to guiding issues or wind etc.

You may notice quite a lot of hot/warm pixels in individual stretched frames, I understand this is normal for this sensor, but is not an issue at all provided you dither often enough, usually every third or fourth frame for me. I also take dark frames some don't.

[ONIKKINEN]

16 hours ago, edarter said:

I've been doing some experimenting to try and find the right values for gain and offset, having watched a video done by Cuiv.  Sharpcap sensor analysis shows that gain 300 is where the S/N ratio drops so I understand that, though this translates to gain 150 in NINA with HGC enabled due to the way that Sharpcap calculates it for Altair TEC cooled cameras. Do the below figures look to be the right ballpark?

Cooled to -5 on the bench
Gain 150 with HGC mode enabled
Offset 260
Exposure is 0.0001 (is this to fast?)
Minimum pixel value is 6

 

Thanks
Ed

 

I would bump up that offset a little bit, with random noise you would almost certainly get 0 value pixels occasionally.