Multi-star FWHM autofocusing with NB filters

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umasscrew39
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Multi-star FWHM autofocusing with NB filters

#1

Post by umasscrew39 »

I finally had a couple of evenings to try the multi-star FWHM feature with my autofocusers since I want to use the sequencer. Unfortunately, I am having trouble with using my NB filters but this worked with my lum filter. When I attempted it with a NB filter, all that happened was a small red box appeared on the screen instead of the many little yellow boxes surrounding stars. Using the NB filters to get focus on a single star is no problem at all and I have been doing it that way for a few years. Is this just a setting issue I am having as I do see stars, albeit duller than the lum ones as one would expect? Does gain and/or exposure time have to be significantly increased?
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Re: Multi-star FWHM autofocusing with NB filters

#2

Post by admin »

Hi Bruce,

it does sound like the star detection is having trouble with the dimmer stars.

Are you using SC 4.0 or 3.2? The configuration for the star detection has changed between the two versions to try to make 4.0 easier to adjust.

Assuming 4.0,

* first check if the red box is the selection area box, perhaps turned on accidentally. If so, turn it off or adjust it to cover the whole image
* second, turn up the sensitivity option
* thirs, if still having problems, use the display stretch to brighten the stars on screen - in 4.0 this also brightens them for the star detection. Doing this should be effective.

thanks,

Robin
umasscrew39
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Re: Multi-star FWHM autofocusing with NB filters

#3

Post by umasscrew39 »

Thanks much, Robin

Correct- using v4.0.

It is the area selection box. When I did adjust it to cover the whole image it did display like it should by highlighting individual stars. I just was not understanding why that was happening.

Next clear night I will make the other adjustments you suggest and see how it goes.

Thx again
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