Focus question/suggestion

Discussions of using SharpCap for Planetary Imaging
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GSBass
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Focus question/suggestion

Post by GSBass » Sat Sep 12, 2020 5:15 pm

Sometimes it a struggle to focus on planets when seeing is not great and the edge detection and contrast tools in sharp cap don’t really help that much over just regular visual, I have never used fire capture but read a imagining tutorial that mentioned a feature that continuously live stacked the last 8 frames to give you a better sense of focus, if that really works could you make this available in sharpcap. Thanks

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Re: Focus question/suggestion

Post by admin » Sun Sep 13, 2020 12:52 pm

Hi,

so firstly I have some sort of planetary live stacking on the to-do list, although it's unlikely to happen in the near future.

For a practical point of view, you may find that the best option for focusing on planets is the brightness range detection focus option. This will tend to work better for noisy images (like planetary images where you have the gain turned up) than the contrast detection option. It should be much less sensitive to the noise in the image, but still sensitive to the quality of the focus.

Cheers, Robin

GSBass
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Re: Focus question/suggestion

Post by GSBass » Sun Sep 13, 2020 2:14 pm

I was brainstorming this last night and just posted this in cloudy nights for feedback, maybe something to consider?


I’m not a programmer so when I have ideas like this all I can do is throw them out there for others to destroy or embrace but as a newbie sometimes fresh eyes bring better solutions, I’ve used several of the focusing tools, contrast detection, edge detection , they did not work well for me. I read about firecapture image align/stabilization trick and I am looking forward to trying that one, anyway here is the idea, I noticed some companies like sky safari already have digital representations of what your suppose to see through the eyepiece baked in, you zoom in on Jupiter for example and the red spot and moons and other surface features are exactly where they are suppose to be at any given second in pretty good detail. So I’m proposing a match algorithm that does an analysis of your own focused image against a perfect reference image, im thinking you move through focus a couple of times while the analysis is done and on the third pass it will just turn green when the best match occurs. Whether something like this was part of sharpcap or firecapture or even a stand alone program it sure sounds like it would work well, not just on planets and the moon but stars and dso as well.

GSBass
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Re: Focus question/suggestion

Post by GSBass » Sun Sep 13, 2020 2:18 pm

Btw Robin thanks for the tip, I’ll try the brightness detection one next time I am out

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Re: Focus question/suggestion

Post by GSBass » Sun Sep 13, 2020 6:50 pm

Just a follow up on this Robin since your actually working on a Stacking solution, someone had an idea in that discussion of actually adding a rough wavlet to a few stacked images.... that seems to me that it would work as well as the reference comparison idea I had, I noted that at least in the astrosurface program that few frames could be processed and have wavlets added in a matter of seconds so it should be able to be automated for a rough preview, focusing would then be relatively easy with a fresh preview arriving every few seconds to fine tune

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Re: Focus question/suggestion

Post by admin » Mon Sep 14, 2020 7:18 pm

Hi,

certainly adding wavelet sharpening would be a very interesting thing to do – not least because most programs that allow wavelets tend to make the interface incredibly complicated to use and it would be nice to try to put together an interface that was user-friendly!

Cheers, Robin

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Re: Focus question/suggestion

Post by GSBass » Tue Sep 15, 2020 4:11 pm

Might be worth exploring, in my mind you would only need a mid range hf with no adjustments at all because your not trying to do real-time processing, your just wanting a rough more detailed image to focus on, wouldn’t matter if it was ugly :D ..... guess I’m just saying a stripped down one trick pony might make it simple and fast enough to be useful. I actually talked to one person that had a very fast system that goes to the trouble to save a few frames and process them to ensure they were in focus so this would definitely be useful to some of us

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Re: Focus question/suggestion

Post by GSBass » Tue Sep 15, 2020 4:18 pm

The astrosurface guy might even give you his wavlet code if it was something you wanted to pursue, he seems to be writing for the love of it, I already mentioned this to him

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