Has SGP solved SCT auto focus?

I’m still running V3.2 and want to get back to imaging with my SCT, but looking at the forum for this topic, it doesn’t appear that there have been any updates in the past three years or so, since around the last time I investigated this. I started to try installing 4.3 so I could test myself, but it wanted to overwrite my 3.2 installation. I really don’t want to mess up my current installation just to test if there’s any reason to upgrade. Any updates on the SCT focusing status and/or ways to install the 32 bit version without messing with my V3.2 install would be appreciated.



The installer for SGPro will always default to the same place. It can be changed to any location you want, BUT, please be aware that there may be consequences to doing this for some things.

  • SGPro installs all share the same settings. This is usually not a problem, but it’s worth noting that changing a setting in one version of SGPro will change it in all.
  • While newer versions of SGPro will always be able to open sequences and profiles created in older versions, the inverse is not necessarily true. In other words, if you open a 3.2 sequence in SGPro 4.3 and then save it, there is no guarantee that you’ll be able to open it again in 3.2 later. That said, it will probably be OK. If you want to try this, I would make copies of your profiles and sequences first.

What particular update were you hoping to see? We have plenty of users successfully using AutoFocus with high FL rigs. Were you having a problem?

I have a Celestron 11inch SCT (Edge Version) with an Optec focuser. I have never had a problem using SGP autofocus.


Hi Ken,

I should probably have worded that slightly differently. The last messages on this topic are over three years old, and some of the same threads I’d commented on back then. That may mean the problem has been solved, but V3.2 cannot auto-focus on an SCT due to the center obstruction. It bounces around the same calculated level as fewer and fewer stars are detected as stars on either edge of focus. At the time we were all begging for a solution. My question is if this has actually been solved.

As far as the parallel install, that was what I’d read, but when I tried to install it while still running a sequence, the first thing the installer said was that it needed to modify files that were in use, so I aborted at that point. I was able to install the 64 bit version, but when I started it up, it was warning about needing 64-bit drivers, so I punted on that for the moment. I’ll have to give it another try one evening since we’re moving into a bad moon phase and I’m not going to be getting much imaging done.



Thanks Roger,

What versions have you used? Since you’ve never had a problem, is that because you’ve only used 4.x and the problem has been solved, or because there’s something drastically difference between our two imaging trains?



Sorry, to what topic do you refer to here?

For test purposes and to minimize the chances any potential driver update issues, I would go ahead and just install the 32-bit version of SGPro 4. It is guaranteed to use the same driver set you are using now. Then, if you decide SGPro is something you’re interested in using, take the time to move to 64-bit then (or don’t at all unless you are forced to)

One of my OTAs is an 8" SCT and I’ve been using SGP going back to version 3 or 3.1. (currently using 4.3). It took me a while to sort out the SCT with autofocus, but what works for me is:

  • Have AutoFocus ignore/crop the outer 15% of the frame
  • Set up the step size such that with 9 focus points, the defocused stars aren’t more than about 11 HFR
  • Increase the exposure time to catch as many stars as I can as they get much fainter the further out of focus they get

With my ASI1600 I was using Gain 200 and 10s exposures. With my ASI294 it’s Gain 120 and 10s exposures. Yes, it’s a little slower, but it generally doesn’t have trouble finding stars. When it does start having problems, chances are pretty good that my collimation is a bit off and as soon as I fix that everything works again.

Just my experience.


You also need to check “Disable smart focus” in the control panel in the settings of “Use autofocus”.