Auto Focus - Refocus Fail

[kaymann]

Ignore No Stars! - Doing this during the day:

Screenshot 2023-06-19 075440.png (35.88 KiB) Viewed 462 times

See how the Scan step size is 50 will be set to 100
Samples has already been dropped to 2

Screenshot 2023-06-19 080658.png (12.69 KiB) Viewed 462 times

Are these set okay?

I thought you may have said the "In" button was going to be removed?

Randall

[admin]

Hi Randall,

those settings look like they are OK for the next attempt.

The 'In' button remains for manual scans in the inward direction - what I have disabled is the automatic reversal of the scan if it thinks it is moving away from best focus. That's something that isn't shown in the UI (apart from being able to turn the whole 'smart scanning' feature on or off).

cheers,

Robin

[kaymann]

I reread your manual on how to:

• Measure backlash

• Perform a best focus

I will take this new found knowledge and try again tonight (last night was another disaster with no focus achieved - see logs.

I have only two questions:

• should step size be a certain size above backlash to get good results?

• Does using a HyperStar (V4 C9.25) change any of your instructions

Let me follow your manual instructions to a tee and then we will see.

Thank you for your time and patience with my inability to get this right.

Randall

[admin]

Hi Randall,

the step size (and step count) should be chosen together so that the total movement (step size * step count) is sufficient to get from noticeably out of focus in one direction, through best focus to noticeably out of focus in the other. That ensures that the scan should cover enough focus range to find the point of best focus.

There is no need to set the step size bigger than the backlash - once you have configured backlash compensation, SharpCap will move the focuser in such a way as to deal with any backlash issues. The easiest option is to set the backlash compensation to 'overshoot' and then set a value that is clearly bigger than the backlash as the overshoot amount. For instance if you suspect a backlash of about 700, set 1000 as the overshoot - no need to be exact in that case.

Clear skies and good luck!

Robin

[kaymann]

Success on auto focus last night.