Focuser position memory for lowest FWHM

[AndrewS]

I would find it handy to have an indicator of the focuser position when using FWHM.

I.e. when a new low is established for the FWHM, it is kept for reference.  It would be nice to also keep the position of the focuser when that new low FWHM is found.

I realize there are other factors to consider (at least with SCTs), such as approaching the focus from the same side, but I still think it could be handy.  As I'm always mentally noting the position when trying to find focus, it would be convenient to have it on-screen.

A step further would be the ability to return to that position.

 

Thoughts, anyone?

[AaronSmall]

AndrewS,

I would add that it should probably be an average of 5-10 readings of FHWM due to the variability of seeing conditions.  It would be nice to see (no pun intended) right next to the 'active' FHWM.

I think the position of the focuser (and the ability to return to that spot) is going to depend on your equipment and beyond the scope of BYE/BYN.  Guylain will have to chime in on that. 

FWIW, I am looking at a couple projects by Robert Brown on SourceForge that will do just what you want but DIY instead of purchasing the expensive remote focusers commercially available.  His projects are running about $50-$75 USD and are ASCOM compatible.

Aaron

[AndrewS]

Hey Aaron,

I do already have a Pegasus focusing system.  I started doing my own with a Raspberry Pi, but gave up as I didn't have the patience and/or skill to craft a way to mount it to my SCT.

The Pegasus system is definitely not cheap, but I am happy with it, other than the eternity it takes to change gross focusing position (e.g removing focal reducer, etc).

As it's a stepper, the position is reported to (and adjustable through) BYE via ASCOM.   I don't recall, at the moment, if you can type in an absolute position to go to, but I'm sure it's part of the instructions that BYE would have access to.

I wouldn't necessarily disagree with an average of the readings, but as FWHM currently tracks only the low, I would find that acceptable.

I'm really just looking at a way to automate what I'm doing, mentally.

I have TheSkyX Pro which has autofocus, but I'm having issues with it and my 7D MkII (random disconnections), so I haven't really been able to get autofocus to work.  Once it disconnects, it bails on the process.

I'll add that I have zero issues with BYE disconnecting.  Not sure what's going on with TheSkyX.

Cheers,

Andrew

[astroman133]

Aaron,

The reported FWHM and HFD values by BYE are already averages based on a changeable setting (see the LiveView area of the settings screen). For me I set it to 20 frames.

I am a retired software developer and when I could not find a camera control program for my non-DSLR cameras that had all the features that I wanted I wrote my own. It does what you suggested by displaying the focuser position at which the smallest HFD was calculated as well as graphs of the HFD and focuser position values during the focusing run. I can also easily send the focuser to a given position, but it is on a separate panel and must be manually entered. I have never found the need to send the focuser back to that position, but that may be because I always end my focusing process with a series of small inward moves of the draw tube.