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using your main camera for imaging and auto-guiding
Posted: Sat Mar 16, 2019 4:19 pm
by numchuck
I've been using a cgx mount , unguided , with SharpCapPro , to do live stacking , since late spring a year ago ; and lately , i've been reading about PHD2 . Long ago , a friend had a very nice CCD built by SBIG that had 2 sensors in one camera body ( one for imaging and one for guiding ) . Well , all this got me thinking : Why couldn't some really smart programmers ( like the authors of SharpCap and PHD2 ) get together and make their 2 programs work together , so that one , imaging camera could send frames to both programs at the same time , for both imaging and guiding ? My QHY183m CMOS is usually set for 6 to 8 second exposures , anyway . I know that you , with observatories , might not get excited about this , but for those that have to set up a mount , every night , this could be useful . Incorporating dithering and live stacking together would be spectacular , at least to me . What do you think ? Is this dumb ?
Re: using your main camera for imaging and auto-guiding
Posted: Sat Mar 16, 2019 9:17 pm
by admin
Hi,
This idea doesn't really work because the guiding camera needs to take images every couple of seconds in order for the guiding to respond fast enough to deal with tracking issues without the main image being affected. However the main camera needs to take longer exposures than this otherwise you end up with a very noisy final image because paying the cost of the read noise in every single short exposure that you take.
Cheers, Robin
Re: using your main camera for imaging and auto-guiding
Posted: Sat Mar 16, 2019 10:28 pm
by numchuck
Robin , Thank you for answering . I was just hoping to avoid the complexity of another camera and guide scope . Let me take this opportunity to express my appreciation for all your work on SharpCapPro . I've had telescopes for most of my 54 years but your program has brought more joy to me than any equipment purchase I've ever made . I'm finally able to "see" the galaxies that I've sought for so long . I'm truly grateful .
Re: using your main camera for imaging and auto-guiding
Posted: Sun Mar 17, 2019 8:38 pm
by admin
Thank you for your kind words! Receiving comments like that from people who really enjoy using SharpCap makes it all worthwhile.
Please do share some of your galaxy photographs when you have a chance.
Cheers, Robin
Re: using your main camera for imaging and auto-guiding
Posted: Fri Jun 07, 2019 11:46 am
by Astrojunk
It could work very well if every x frame was used as a guide frame. It would't really help with PE, but could be useful with less than perfect polar alignment over a long exposure. This image was an example using hyperstar and 12s exposures - over an hour the drift is quite noticeable, but I don't currently have a guide scope.
![Stack_308frames_3697s_WithDisplayStretch (Medium).png](./download/file.php?id=1838&sid=0bc16f9e2e9ee74e00fbb8f5e44de8dc)
- Stack_308frames_3697s_WithDisplayStretch (Medium).png (869.26 KiB) Viewed 3397 times
Re: using your main camera for imaging and auto-guiding
Posted: Thu Jun 13, 2019 8:06 pm
by numchuck
I finally got tired of the drift so I bought a guide scope and camera . Often times it didn't matter because SharpCapPro does such a great job of stacking ; but sometimes my targets were too big and too close to the edges .