Camera's physical shutter triggering when attempting to take darks

[UVicObservatory]

Hello,

We have an old Princeton Instruments Pixis CCD camera with a physical shutter. I'm trying to modernize the imaging process on our telescope, so I've been experimenting with several different imaging programs connecting through Princeton's ASCOM driver. (their ASCOM driver also requires their SDK to be installed; I got them to give it to me last summer)

I'd prefer to use SharpCap specifically because it's able to connect to the camera more-or-less instantly (whereas NINA takes 3 minutes or so). The only issue is that when I try to take dark frames with SharpCap it triggers the camera's shutter. Using the exact same setup with NINA does not. I've tried it on two different computers:

Computer 1:
Windows 10
ASCOM Platform 6.6 SP2
SharpCap 4.1 (installed Summer of last year)
Princeton's SDK and 64-bit ASCOM driver

Computer 2:
Windows 11
ASCOM Platform 7.0 Update 2
Sharp Cap 4.1 (fresh install from the website as of August 18)
Princeton's SDK and 64-bit ASCOM driver (same version as computer 1)

Any help you can give would be appreciated!

Thanks,
Erica

[admin]

Hi Erica,

right now, SharpCap doesn't have a way to do what you want (in fact you can't control the opening of the shutter at all for a camera being used via an ASCOM driver in SharpCap). This is probably partly a reflection of the fact that SharpCap is most popular amongst users of newer CMOS cameras, which hardly ever have a physical shutter.

I could fairly easily add an extra control into the right hand side panel where you could choose whether opening the shutter was 'On' or 'Off'. That would let you stop the shutter from opening during dark capture, but that would be a manual step to change that control before capturing darks and then change it back after capturing them (at least to begin with). Does that help at all?

thanks,

Robin

[UVicObservatory]

Hi Robin,

Huh, so I guess that means that when you take "darks" with an ASCOM camera currently it just assumes you've got everything covered up? In our case the telescope is open-frame and even with the mirror cover closed there would be light leakage.

With that in mind, adding a setting that would let us manually lock down the shutter for darks would be very helpful! Especially if it could be automated for dark capture either in software or via scripting in the future. Even if we have to remember to manually toggle a setting it will *still* be less hassle than having to perfectly perform a 3-minute connection ritual in order to use the camera

Thanks,
Erica

[admin]

Hi Erica,

OK, look out for the ability to control the shutter in the next update - it will simply be a new control 'Open Shutter' which can be 'On' or 'Off'. That will give you manual control for capturing darks (you could also automate that via the sequencer). I will try to build in some automation later to make that automatically get set to 'Off' when using the 'Capture Dark' tool.

cheers,

Robin

[UVicObservatory]

Thanks for your help Robin!