Call for Donut AFPacks


As we move toward breaking ground in version 2.5, we will be taking a hard look at algorithms used for auto focus. This will start, of course, with star (centroid) detection. As many of you know (especially if you own a scope with a secondary obstruction), SGPro does not handle detection well here (donut stars are detected as several smaller stars with a lower average HFD, then when the donut hole disappears, the HFD suddenly shoots up).

Anyhow… it would be very helpful to us if those of you who own gear capable of creating this type of data were able to share it with us for the development process. We provide an option to do this that is pretty painless, but you will need to upload and host them long enough for us to download them. Regardless of the success of the current method, we just need the data. To grab data from an AF run, go to AF settings, provide a path and check the box:

Thanks for your help!

New Auto Focus Beta is Starting... Please read

Hi Ken,

Happy to help - will dropbox do to transfer them?


Thx! Sure, that’s fine (probably preferred).


Here’s a link - files are uploading now so should be available in 15 minutes.


should be there now. I’ve uploaded three packs with different AF settings. Let me know if you need any more.


Just because this needs to be here:


fresh donuts

Three star fields progressively harder (fewer bright stars). I deliberately started each AF run 240 steps outside the focus point so that AF’s initial outward movement went right to donut land.



I’ll load some in a dropbox Ken - one thing I have found, your current AF routine is considerably more effective if I bin the AF exposures 2x2. I’m using a RCT, which has a large central obstruction (probably the worst case) and my unbinned resolution is 0.5arcsec / pixel.
I’ll try and do both 1x1 and 2x2 AF routines, weather permitting, to show the difference.


Three packs with a 10" RC. Some with 1x1 binning, others with 2x2. There is a globular cluster in the middle, which gives some challenges.


Hi Folks,

2GB of donuts…

Bon appetit!

I hope you mange to solve the star detection problem, the focus algorithm is fantastic with my refractor, but not very good with my Newtonian.




i missed this one.
my datas will be available a soon as i can image (mmm winter is coming…)
FD 5 and FD 3.5 runs.


AFPacks were taken last night using my Celestron SCT-8 Scope with a Optec TCF-S Focuser.


Hope this are what you are looking for,


do you still need donut AFPacks? i seem to have a case where autofocus fails, however, i’m not 100% it’s simply because of the algorithm. could be the focuser slipping.

can the AFPack collection be turned on at the start of the night and will it then save all focus runs? the target rises too late at night for me to do anything manual.