Hi,
the FWHM focus tool (like all the SharpCap focus tools really) is designed to help you get perfect focus as long as you already have reasonable focus. That means that as a starting point you need to be seeing something on the screen (blobby stars for FWHM, slightly blurred moon for contrast measurement, etc).
The step sizes depend on your equipment setup, so it's impossible to give any exact numbers. I tend to keep the 'fine' step at about 1/4 of the course one, and I have 'course' set up so that it will go from noticeably out of focus one side to out of focus the other in about 8 to 10 presses.
cheers,
Robin
Automatic refocus with ZWO EAF
Re: Automatic refocus with ZWO EAF
Robin,
I will take that advice, duly noted sir. Thank you-
I will take that advice, duly noted sir. Thank you-
Clear SkiesRe: Automatic refocus with ZWO EAF
Robin,
Last night I was set up in SC FWHM. Practice focus run. medallion hanging on the wall, approx. 2 inch diameter piece. My scope was maybe 15 feet from the medallion. My outward focus tube was extented almost to the end 90mm max end outward focus.
Take a look at the graphs. Would this be practical go by for practice focus run indoors?
I was getting an error. "Refocus failed due to: Sharpcap did not find a best focus position in the range 21513 to 22017.
However, looking at my snap shots I took, they were decent and in focus. as you can see in the screen shots the medallion is in focus.
the other attempt graph looks pretty good, all green points.
Any advise please. Thanks!
Last night I was set up in SC FWHM. Practice focus run. medallion hanging on the wall, approx. 2 inch diameter piece. My scope was maybe 15 feet from the medallion. My outward focus tube was extented almost to the end 90mm max end outward focus.
Take a look at the graphs. Would this be practical go by for practice focus run indoors?
I was getting an error. "Refocus failed due to: Sharpcap did not find a best focus position in the range 21513 to 22017.
However, looking at my snap shots I took, they were decent and in focus. as you can see in the screen shots the medallion is in focus.
the other attempt graph looks pretty good, all green points.
Any advise please. Thanks!
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Re: Automatic refocus with ZWO EAF
Hi,
the focus detection relies on finding either a dip in the graph with clear increases on both sides (star detection) or a peak with clear drops on both sides (contrast detection). In the first two screenshots we can see that pattern and SharpCap finds the best focus position, but the third is less clear - partly because the screenshot only shows part of the graph, but I suspect that the pattern wasn't there. Since you are getting dips then I guess you must be using one of the star detection tools, but on a part of the image rather than a star, which is possibly causing the issue.
cheers,
Robin
the focus detection relies on finding either a dip in the graph with clear increases on both sides (star detection) or a peak with clear drops on both sides (contrast detection). In the first two screenshots we can see that pattern and SharpCap finds the best focus position, but the third is less clear - partly because the screenshot only shows part of the graph, but I suspect that the pattern wasn't there. Since you are getting dips then I guess you must be using one of the star detection tools, but on a part of the image rather than a star, which is possibly causing the issue.
cheers,
Robin
Re: Automatic refocus with ZWO EAF
Robin,
Thanks for responding. Next clear night, I plan on further testing FWHM mode. As Always, appreciate your feedback.
Happy Holidays!
Thanks for responding. Next clear night, I plan on further testing FWHM mode. As Always, appreciate your feedback.
Happy Holidays!
Clear Skies