Can you guide with Sharpcap?

Anything that doesn't fit into any of the other forums
Post Reply
zerolatitude
Posts: 48
Joined: Mon Mar 01, 2021 5:24 am

Can you guide with Sharpcap?

Post by zerolatitude »

I dont need to guide in my situation (very short exposures + plate solving every now and then suffices). So I dont know much about guiding except the general principle.

This makes me curious. Can a capture program like SC guide simultaneously, at least for short exposures? Consider:
1. If OAG is better than guidescope, the actual image would be even better. Bonus - you need only one camera and scope.
2. SC can already pick out stars
3. SC can platesolve (with other programs of course) and send corrections to the mount
4. SC can measure drift at pixel level (as seen in live stacking)

So conceptually, could it keep analysing the drift data and sending corrections to the mount? Would this work - at least for short exposures? Or is it more complex than that?

Another part of me says is it was that simple it would be out there by now.

But still... just wondering.
User avatar
admin
Site Admin
Posts: 6396
Joined: Sat Feb 11, 2017 3:52 pm
Location: Vale of the White Horse, UK
Contact:

Re: Can you guide with Sharpcap?

Post by admin »

Hi,

there are two ways that you can imagine doing this...

1) A bit like PHD - some sort of calibration to work out which direction the image moves for which mount movement direction (and how far), followed by nudges after each frame. This would work better for shorter (<30s) exposures, so the drift is small each frame. The tricky part here is the calibration - I tried that for the 'Feature Tracking' and discovered that it's hard to get right.

2) A plate solve based recenter every so often - this would prevent large drifts building up during live stacking as every 5 minutes or so the target would be re-centered. This could probably be built already using the sequencer in SharpCap 4.0

On the whole though I'm not sure how much this brings to the average imager - if your tracking is so bad that big drift during a live stack is a problem then you are probably going to be getting issues with elongated stars in the subs too. Traditional guiding (with a guide camera) can fix this as it can adjust during a sub. Any sort of guiding based on the main camera can't fix this as it can't adjust until each frame is complete.

cheers,

Robin
zerolatitude
Posts: 48
Joined: Mon Mar 01, 2021 5:24 am

Re: Can you guide with Sharpcap?

Post by zerolatitude »

Yes, I do use the periodic automated plate solving, which works quite well.

I understand that with just one camera the software will have to wait till the exposure is complete, so was curious if it could be done automatically after say every frame or two, basically taking over the plate solving part.

Anyway, understood and thanks.

Maybe we should now open a new branch of AP specifically for short exposure imaging :D
User avatar
oopfan
Posts: 959
Joined: Sat Jul 08, 2017 2:37 pm
Location: New York
Contact:

Re: Can you guide with Sharpcap?

Post by oopfan »

"Maybe we should now open a new branch of AP specifically for short exposure imaging"
Done:
Electronically Assisted Astronomy (EAA)
https://jareksastro.org/eaa.htm
Post Reply