A few questiongs here...
I've been really trying to dial Autofocus in lately. I've had it working pretty well for some time but I can't focus well pointing east because of a light dome from the next city over. I usually manually focus a target for the first hour or so and then go to auto focus then the target gets a little higher and away from light pollution.
Is it possible to use the same settings for the light pollution to the east and the darker sky later in the night? Does light pollution affect the accuracy of the FWHM readout? Other than the black threshold, what other settings would be the most critical for dealing with light pollution?
I use the multi star mostly for my wide field refractors. My wide field rig is around F4 so I know the critical focus zone is very small. My thinking is that multi-star would take the entire frames tilt/field curvature into account when focusing and hopefully give better results. My tilt and flattener are pretty dialed in but it's always there to a small degree.
Is multi-star better for wide field rigs and fast optics focusing? Would single star have an advantage on fast or slow focal ratios?
FWHM multi star VS single star autofocusing tool
Forum rules
If you have a problem or question, please check the FAQ to see if it already has an answer : https://www.sharpcap.co.uk/sharpcap-faqs
If you have a problem or question, please check the FAQ to see if it already has an answer : https://www.sharpcap.co.uk/sharpcap-faqs
-
admin
- Site Admin
- Posts: 13296
- Joined: Sat Feb 11, 2017 3:52 pm
- Location: Vale of the White Horse, UK
- Contact:
Re: FWHM multi star VS single star autofocusing tool
Hi,
my preference is to always use the multi-star version these days. I think that it gives more stable readings because you are taking the measurement from many stars which means that noise levels on an individual frame have less effect on the readout number, and that's important. As you say, using the multi-star variant will tend to help you get the best focus across the whole field-of-view rather than concentrating on the exact focus on a particular position.
I'm not sure that I've ever really thought about how the particular settings might interact with light pollution – I think the algorithm should largely ignore any background level, since it looks at the brightness of the star compared to the dimmest pixels nearby.
Cheers, Robin
my preference is to always use the multi-star version these days. I think that it gives more stable readings because you are taking the measurement from many stars which means that noise levels on an individual frame have less effect on the readout number, and that's important. As you say, using the multi-star variant will tend to help you get the best focus across the whole field-of-view rather than concentrating on the exact focus on a particular position.
I'm not sure that I've ever really thought about how the particular settings might interact with light pollution – I think the algorithm should largely ignore any background level, since it looks at the brightness of the star compared to the dimmest pixels nearby.
Cheers, Robin