Dither without guiding questions

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bokemon
Posts: 26
Joined: Wed May 26, 2021 3:21 am

Dither without guiding questions

#1

Post by bokemon »

Hello,
I want to use this with the Live Stack feature for EAA. I have an ASCOM mount (CEM25P) and ASI294 camera, but no guide cam.
Q1) Why is dither interval based on time and not number of frames?
Q2) Why is does Sharpcap keep the camera continuously exposing and then throwing away frames ("frames ignored"), instead of just pause, dither, pause, take picture?
Q3) I assume "settle threshold" and "maximum settle time" don't apply here?

The only setting that seems to cause "pausing while dither" is "reduce exposure while dithering", but this still results in the live stacking throwing away frames.

Well, the most important thing is that it doesn't actually seem to be dithering. Yes, Sharpcap can connect to the mount. But I am watching some hot pixels in the live stack, and they don't seem to be moving.
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Re: Dither without guiding questions

#2

Post by admin »

Hi,

Q1 and Q2 are all related to the fact that SharpCap up to and including 3.2 works like a video camera (taking frames all the time) and live stacking was built around that. In those versions of SharpCap there was no way to pause capturing.

SharpCap 4.0 has a still capture mode, but so far it's not compatible with live stacking (selecting live stacking puts it back into video capture mode). Fixing up both of those is on the TODO list for after the release of 4.0 (4.1?)

Q3 - yes, correct - settle threshold and max settle time have no effect, but the minimum settle time is used (after the pulse guiding operation is complete).

Now, the mount not moving...

SharpCap sends pulse guiding requests to the mount - the details go into the log. You can also turn on additional logging for mount communications in the SharpCap setttings which will record all SharpCap<=>Mount communications in the log.

If you can find the log for the session where you had a problem, please post it here and I will have a look. Otherwise, try to capture a log next time and turn on the additional logging. Also check the pulse guiding settings (if there are any) in your ASCOM driver configuration. SharpCap gets to tell the mount which direction to guide in and how long the guiding motion should last, but does not set the guide rate at the moment - maybe it should.

cheers,

Robin.
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