How to use focus assist with a focuser that has a motorized focuser with a handwheel only?

[pastorgalactico]

Hello;

How do I use focus assist with a focuser that only has a motorized focuser and a remote control?
I've tried using this tool with multiple stars, but it doesn't seem to work.
I'll post a screenshot tomorrow, as all that appears is a graph with green bars and two numbers: 25 and reset. The graph doesn't change even when I use the focuser.
Could this be due to incorrect settings?
Regards

[pastorgalactico]

Hello;

This is the image.

How do I configure this?

Enfoque.jpg (95.19 KiB) Viewed 435 times

[Jean-Francois]

Hello,

on the right you have the mention that SharpCap does not detect stars ("No Stars !").
The value "25" is some start numerical value for having something in the graph (in place of zero).

What you need first is to change some settings until SharpCap detects some stars => ... no star = no focus
The first step is to check the size and the position of the "red rectangle".
Next step is the parameters on the left. Max brightness is maybe too low.

Can you show a screen capture with the sky image ?

Regards,
Jean-Francois

[Jean-Francois]

... and here:
viewtopic.php?t=9724

[pastorgalactico]

Hi;

I was trying it with this image.
I asked the AI ​​and this is what it told me.
What I miss is a complete Spanish translation of the program.

Regards

IMG_20260830_083939_598.jpg (86.5 KiB) Viewed 428 times

IMG_20260830_101327.jpg (110.63 KiB) Viewed 428 times

[Howardk]

Its not seeing any stars

Try increasing your camera exposure and/or gain

Increase max brightness in left hand box to 75%

See if focus assist finds stars

[pastorgalactico]

Hi;
Last night I tried again with the same object and at least it seemed to be working.
One thing that was happening is that in live stacking, if I wanted to use sharpening assist, the live stacking would close.
How can I prevent that?
In other words, how can I use sharpening assist while performing live stacking?
At what number of stars does sharpening assist start to work better?
Regards

SAVE_20260831_073933.jpg (322.65 KiB) Viewed 379 times

SAVE_20260831_073959.jpg (232.29 KiB) Viewed 379 times

[admin]

Hi,

one thing to note is that SharpCap will not use fully saturated stars for this measurement, so if you are testing with an existing image (a processed one - as the images above look to be), all of the stars may have peak values at or near maximum, so SharpCap will ignore them for FWHM measurement.

If you think about it, this is required - FWHM means 'Full Width Half Maximum'. If the star is at or near saturation then we don't really know what the maximum is - it could be the value seen by the camera, or it could be something much brighter, so for a saturated star you can't really measure the FWHM at all accurately.

cheers,

Robin

[pastorgalactico]

No, no, those images were taken later.
The only thing that could be happening is that I'm using live focus assist with 2-second exposures. Last night, with focus assist, that image came out in two different ways, processed with Astrotropics Lab, and I was using focus assist with up to 16 stars.
I have to try it with just one star and see the difference.
What I have noticed is that when it's in focus, with very low green bars, suddenly high red bars appear, and I don't know why that happens.
Could it be due to overexposure or poor viewing? Two numbers appear, and the first one is usually higher than the one below it, and you can see how the focus changes as the mirror and the telescope adjust.
Regards.

[admin]

Hi,

it's worth knowing that SharpCap uses a value of 25 as a 'default' bad value if there are insufficient stars to get a valid measurement of the FWHM. It sounds like you may be getting a '25' pop up now and then perhaps because the number of stars you are getting is close to the minimum and sometimes a frame will come along that is a bit harder to find the stars in, putting the count below the minimum and then you get the 25 value. Ideally you would want to have the typical star count being measured as 30 to 50 or more when in focus. The count will drop as you move out of focus as the stars blur and the fainter ones become too dim to detect due to the blurring.

cheers,

Robin