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Old 21-11-2018, 12:54 PM
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Bart
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SGP Autofocus Setup Help

Hi,

Is there someone here that can help me with autofocus setup in SGP. It seems to be the weakness in my system. I seem to be getting a 50% success rate and I am chucking out or having to use too many low quality subs.

Either that or I need to learn how to script for MaxIm DL so I can use FocuMax which seems to work very well.

Thanks.
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Old 21-11-2018, 02:27 PM
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Benjamin (Ben)
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My weakest point too but seems related to the focuser rather than SGP and settings. Having said that I did refine and tighten up my standard Skywatcher focuser and found after some trial and error I had to compensate about 150 steps in (heavyish gear attached) and its seems to work (using a Rigel nSTEP system). When focusing I bin 2x2 to reduce noise (with narrowband especially SGP can mistake noise for stars) and worked out my step size as per the SGP instructions. Could change star detection parameters and subtract darks I guess but not got that far. Not game to use filter offsets given the focuser isnít that reliable - would get slightly different results every time I think. Not much help really but keen to see others responses too. Probably a lot more I can do as well. For a while I didnít use the autofocus routine and got close to focus with a Bahtinov Mask and then manually fiddled with the focuser unitl I had the best HFR readings I could get. Quite quick to do and probably quicker than the autofocus routine.
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Old 22-11-2018, 10:04 AM
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I have followed all the steps in SGP and I can get reasonable curves most of the time although I get a lot of messages saying the HFR of 1.9 is higher than the expected 1.2 and then the frames are out of focus and you can see where it should have focused and it can be alot. I've tried to use smaller steps and more data points but it ends up with dog eared curves and even poorer focus. I've tried larger steps and less data points and that can be as hit and miss.
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Old 22-11-2018, 02:16 PM
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One of the key things I found was to try and start as close to focus as possible first. So do this manually if you have to with SGP. Then it's all about getting the step sizes right.

If you play around with the step sizes, and are reasonably close to focus to star with, you should get a 95%+ success rate which is what I am getting. Then leave the settings as they are and you are up and running.

John K.
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Old 22-11-2018, 04:50 PM
garymck (Gary)
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Hi,
I've never found SGP's autofocus focus to be reliable. Have spent nights trying to get it to work reliably to no avail, both with a motorised Moonlight focuser and homebrew stuff as well. One of the main reasons I'm looking at other software. There are many complaints about it and many have reportedly requested improvements, but the developers appear to have ignored these over several years. There are other issues with it, but the main reason it seems to be popular is that it is relatively affordable.

Gary
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Old 23-11-2018, 07:12 AM
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Is anyone using CCDCiel? Doesn't that have a focus trainer like Focus Max?
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Old 23-11-2018, 11:46 AM
garymck (Gary)
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Quote:
Originally Posted by Bart View Post
Is anyone using CCDCiel? Doesn't that have a focus trainer like Focus Max?
I'm about to try it - when the weather clears. Although I have used it to take images, I haven't used the autofocus routine yet (it appears to be much more stable than SGP even though it is technically still in Beta. I don't see any training options (not familiar with Focusmax) though. Will post after next clear night.

The other program I'm going to try is Voyager .....

Gary
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Old 23-11-2018, 01:37 PM
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Does anyone have a script to run Focus Max from MaxIm in sequence? I do not understand that stuff and was thinking that might be the alternative as I have FM 3 and MaxIm 5.

Last edited by Bart; 23-11-2018 at 05:57 PM.
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