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Altair AA183M Pro not completing sub exposure
Posted: Sat Sep 13, 2025 3:45 pm
by Roycp
I'm trying to use an Altair 183M Pro camera with Sharpcap Pro 4.1.13724 and all works fine (plate solve, gotto etc.) however the sub exposures do not complete, if I set them to 120 seconds they restart after 10 to 15 seconds. The FITS info records the exposure as 120 seconds when it is clearly not.
I have tried latest drivers, different PC etc.
The issue does not occur with with my Altair 296C or 290C3
Subs run to their set time with Sharpcap Pro 4.0.9571 so I find my self obtaining a target with 4.1 and capturing images with 4.0 - very long winded and I miss the functionality of the latest version of Sharpcap!
The same truncated sub issue occurs with NINA and AltairCapture so I'm thinking driver issue but verision 4.0 is fine..
Thanks.
Re: Altair AA183M Pro not completing sub exposure
Posted: Sat Sep 13, 2025 5:34 pm
by admin
Hi,
Interesting... I have the same model here and I see the same problem - I will investigate and come back to you.
cheers,
Robin
Re: Altair AA183M Pro not completing sub exposure
Posted: Sat Sep 13, 2025 8:46 pm
by Roycp
Thank you Robin,
at least you can duplicate the problem.
Hoping you can identify a solution
Thanks
Roy.
Re: Altair AA183M Pro not completing sub exposure
Posted: Sun Sep 14, 2025 12:59 pm
by admin
Hi Roy,
my experiments reveal that the exposure you get is about 85% of what is requested up until you get to about 104s of set exposure. Beyond that, the exposure drops back to close to zero and then starts rising again as you go up to 120s and beyond. As a workaround for now, set the exposure to about 104s, which should give real exposures of about 88s, which seems to be the longest this camera can manage with the current bug.
I have also resolved the problem that SharpCap shows the expected exposure not the actual exposure for the 'last frame'. I hadn't expected there to ever be a difference, but have now written code to pick up the actual exposure time if it is shorter (this will also get copied into the FITS headers I think)
cheers,
Robin
Re: Altair AA183M Pro not completing sub exposure
Posted: Mon Sep 15, 2025 7:24 pm
by Roycp
Thank you Robin, I will give that a go.
Is a potential fix something that will make it to the next 4.1 release?
Roy
Re: Altair AA183M Pro not completing sub exposure
Posted: Mon Sep 15, 2025 10:14 pm
by admin
Hi,
I've reported the issue to Altair, as it is a bug inside the SDK that they provide to control the cameras. I haven't got any information on when we might expect a fix, sorry.
cheers,
Robin
Re: Altair AA183M Pro not completing sub exposure
Posted: Thu Sep 25, 2025 9:55 pm
by mrjhd
I am having the same exact issue while using NINA. Has there been a fix yet?
Re: Altair AA183M Pro not completing sub exposure
Posted: Fri Sep 26, 2025 12:46 pm
by admin
Hi,
no, no fix yet - I would suggest reporting this issue direct to Altair as maybe they will give it a bit more priority if it is reported by a number of users.
cheers,
Robin
Re: Altair AA183M Pro not completing sub exposure
Posted: Sat Oct 04, 2025 11:47 pm
by mrjhd
I have been in touch with Altair. They have worked out the problem and are going to update firmware of the camera. Hopefully will be sorted anytime now.
Re: Altair AA183M Pro not completing sub exposure
Posted: Mon Oct 06, 2025 12:42 pm
by admin
Hi,
that's good news - when you get a firmware update from them that solves the problem, it would be great if you could share the details here - that would give anyone arriving at this page with the same problem a pointer to the solution
cheers,
Robin