thanx

OHK, I've tried to make the image in my previous message #58481 visible and attached a log file. Here is the attached log file for reference...

Looking at your screenshot I might hazard a guess that the star detection is picking up somethings that are not actually stars. Hard to say what, might want to manually focus, then take some light, bias, and dark frames, combine them and just take a look for bad pixels, dust fragments etc...

@astrodd: Regarding "I will also start a temperature vs position log"

FYI, if you have a focuser or weather temperature sensor (e.g. PPB), regularly use autofocus, and your Kstars is current, then the focus/temp log is created for you already (just enable it). See this post:
www.indilib.org/forum/general/7106-autof...r-and-hfr.html#55073

And coming soon (TM), Hy is working on an Analyze tab to go into Ekos, which I'm hoping will allow you to plot this kind of information within Ekos, and allow you to check what happened during a session.
photos.google.com/share/AF1QipNMo5MbxUuB...MTNqY19raUZvM3Q0Mmh3

invent.kde.org/education/kstars/-/merge_requests/50

I think this will be a valuable contribution!

That certainly may be an issue, but I strangely think it's more than that perhaps. When I choose a star and zoom in with a subframe, I can see that what obviously is a defocused star may start out with a single outline and HFR, with subsequent focus exposures become multiple smaller outline circles each with their own HFR values which are lower. These cluster of smaller values are obviously within the same previous ring of the initial star, so it thinks it's actually has improved focus (but it hasn't).

If I get a clear night again, I'll try and capture a sequence of screen shots to illustrate.

I am new to autofocusing...

About a month ago I bought a ZWO EAF for my AT72EDII.
Installation - easy. Set-up - easy. Works perfectly with Ekos.

About two weeks ago I bought a new telescope - TPO RC6.

Today I received a new (second) ZWO EAF.
Installation - not easy at all. Curved surfaces on RC6's focuser. The EAF bracket holes do not match - had to drill. Had to use some spacers, etc.
Luckily I had everything handy at home.
Took me a couple of hours to install it right.
Set-up - relatively easy. I had to put it really close to the right focus before Ekos could pick up.
When I started, it was close but not close enough and Ekos was picking some noise patterns instead of stars.
I was about 500 steps away from the right focus.
Once set-up it worked perfectly with Ekos.
Shooting the Bubble nebula right now.
No focal reducer yet. Had to use loooong exposures (with L-eNhance filter).

To me, that seems to suggest that either you had been too far away from focus when starting the AF run, or that your initial step is too large.
I'd try to first do a run with the polynomial AF, to be sure you are close to focus, and then look at that curve. Check the distance where it is a nice V-curve / parabola. Your initial step times 5 should still be within that curve! I.e., with your step of 200, the range focus±1000 should show a nice curve.
Also, do you have backlash in the focuser, and how much? Is it compensated?

OK, I'll try a Polynomial AF after a Bathinov mask focus, reduce the step size to 100 and the max range. Pegasus Astro suggests a backlash value of 30-40 for their FocusCube, but I've seen suggestions here to set it to zero (perhaps based on other focusers). I will increase my exposure time, and reduce my inside annulus from 20 to 0 just to try and get more data.

Thanks!

Jerry,

I think that may be a problem with your filter not being parfocal on a OSC sensor. I have seen a very similar problem with a dual band filter where my O3 was out of focus while the Ha was used to achieve perfect focus at that wavelength.

I would suggest taking out the filter and running the autofocus routine without it (only with a UV/IR cutoff filter in place - may not be necessary, as you are using a stock DSLR, I take it). Then see if the problem is resolved. The Linear algorithm works perfectly for me, but I am using narrowband exclusively.
Jo