I searched the forum for all posts about Altair cameras and here are my findings:

1. ALTAIR ASTRO HYPERCAM 183C ProTEC: Not compatible
2. Other people mention that they use Altair Astro cameras with the 183 and 294 sensors (but it is not mentioned how it works out for them)

However, it is not clear to me if the Altair Astro cameras are as well supported under Indi as for example ZWO cameras.
I am considering to buy one of these cameras but it is very important for me the camera will work perfectly with INDI:

Altair Hypercam 294C PRO Color
www.teleskop-express.de/shop/product_inf...ensor-D-23-2-mm.html

Altair Hypercam 183C PRO Color
www.teleskop-express.de/shop/product_inf...Sensor-D-15-9mm.html

I would prefer to use Altair over ZWO if possible due to these reasons:

• From the reviews I have read, it seems like the Altair cameras are better build quality
• A big plus is that they have an Anti-fogging heated optical window. I read many places on the internet about people having issues with ZWO sensors frosting up and I would like to avoid that
• The Altair cameras have 4GB RAM frame buffer and that will make it easier to do video
• I heard that the amp glow of the ZWO cameras are a lot worse than it is with the Altair cameras (maybe this can be explained by the image pixel resolution that is a tiny bit reduced on Altair cameras compared to ZWO cameras with the same sensor)

Are both cameras mentioned above supported by INDI?
I wonder if the Altair Hypercam 183C PRO Color is the same model that is mentioned to be "not compatible" elsewhere on the forum?
And of course I would also like to hear about experience with any of the above cameras related to INDI and/or StellarMate.

For planetary I am actually also considering Altair GPCAM3 290C USB3 Color :
www.teleskop-express.de/shop/product_inf...-Sensor-D-6-4mm.html

So any experience with that is also interesting for me.

Please contact Nick Smith over at Altair. The cameras work well for the most part. However, the SDK is out of date. I asked him to send me v46.16909.2020.0404+ of the SDK but I haven't heard back yet. Maybe if you try at your end, the cameras would be better supported in the updated SDK.

I have been in contact with Altair Astro today about this.
They would like to provide the SDK, but their current SDK version does not support the newest Altair Astro camera models on Linux yet.
So they have a development task that they need to finish before we can get a new SDK version that has Linux support for their newest models.

However, between the lines of the messages, it looks like official Linux and macOS support is coming in the future for Altair Astro cameras.
So I am very happy to hear that. They just want to make sure that Windows is covered first since it is currently 99% of their market.

I asked them if I could subscribe to any updates in relation to that, and I will of course share here on the forum if I hear anything new.
Untill then I will wait a bit with the camera purchase and see what happens

I am a happy user of the Altair Hypercam 294C Pro with Ekos/Indi. I can recommend this camera. The current driver does all it needs to do, except for one feature, which I like to discuss here:

There seem to be no support for HCG mode. And I am starting to understand that the driver needs to set this. I can give it a try to implement it in the driver. I see a few options:
1. Automatically enable it from gain 900. This is the way SharpCap Pro controls this setting.
2. Make it a HCG On/Off setting in the INDI driver panel.
3. Make it a HCG-enable-from-gain numeric setting. The driver will set it automatically when gain is at or above the given gain threshold.

Option 1 has the upside of easy of use, but obvious downside that the driver needs to test on the camera type. Not really generic. Option 2 has the downside that one would forget to change it when modifying gain settings in Ekos. Option 3 is still generic and convenient. Obviously my preference. It looks like the camera api has a function to see whether the camera has conversion gain capabilities. So the setting could be made conditional possibly. I may need some help from the experts possibly.

Please advice on the need for HCG and the preferred implementation.

I've implemented #3. If the gain becomes less than theshold, should it switch to low conversion gain or stay at high ?

EDIT: I made it switch to LOW gain if the threshold is below the limit. This has no effect if the Gain Conversion mode is set to HDR.

Thanks Jasem, you are so much quicker than I can be in this!
I would indeed also go back to LCG below the threshold. And to HCG when >= threshold. Is it already on github? I will check. I can test it tonight if available. Looks like we will have some clear wheather.

I implemented it slightly different. > threshold HCG, <= threshold, LCG

Yes it's pushed to Github.