I have been having trouble with autofocus. Unfortunately the Focus log from last run did not have a jpeg, I suspended it before it finished. Briefly; after beginning the autofocus run well (FHM decreasing, then increasing to form a nice "V’), the focuser graph took a dive and did not recover. I checked the clutch, its tight.
My question: should I be putting some parameters into the “Other” window? My step size is 200, and I saw on another forum post that backlash can be set at 3-5 times step size. Should I check “Backlash Compensation”/"Compensation “IN”/Compensation step size “200,” or is it “600”?
I will try again tonight and see if I can produce a log that can be analyzed.
Thanks, Ed
Jared:
Its a Moonlite with the High Rez motor on a C11 edge working at F/10. Camera is an Atikl 4000 with the Atik filter wheel. It runs through their mini-controller.
I think another problem is that I was trying to focus with a V photometric filter, and I hd to go to 20 seconds to get more stars. I will switch to Lum, which is almost parfocal with the V.
If you’re referring to a Crayford focuser than you likely don’t need any backlash compensation. How did you get to using 200 steps?
I’m unfamiliar with how restrictive photometric sensors are but you very well may be right. If you can include a screenshot of the auto focus graph or turn on auto focus packs and send us a pack we can better assist.
Thanks, Jared. The steps were suggested by an experienced user. I have been trying varying numbers of steps. The suggestion was 200. I calculated 150. I do save focus packs and will try to get one or two tonight.
Ed
If you are focusing with the primary focuser on EdgeHD11 - as I am - then yes the Other settings are critical and you should have backlash compensation set to the equivalent of 1/4 - 1/2 turn of the primary focuser knob. That could be any number of steps for a given focuser - but mechanically it should correspond to 1/4 - 1/2 turn of the knob. It may be a big number.
And ideally you should set things so the focus curve is taken while turning the knob ccw.
It obvious that, being new to all this, I have not provided the information needed. The Moonlite is the second focus unit, I do not use the primary focus unit except to originally achieve focus (or near focus). I then use the Crayford Moonlite exclusively after locking down the mirror. I will have another go at the autofocus, go through the tutorial again, do the calculations, and make sure I have logs with graphs. If the calculated steps don’t work, I will try other steps and see if I can improve the focus. If all that fails I will send logs.
Hi - sorry if I misunderstood your setup. Either way the same principle applies. The focusing mechanism will have some slop - and you use the backlash setting on the Other page to set that to a good value that is not too short and not too long - so that focus curves are repeatable. If you can turn the mechanism by hand and watch a star in view, you can get a feel for how many degrees of rotation it takes to go back - and then forth - in a repeatable way. Then you find out how many steps it takes to do that rotation - and enter it as backlash in the Other page.
Thanks to all who responded. From what I can tell, there is zero backlash and most of my problems seem to be resolved by adjusting steps.On the last few nights the focus routine has run well.
Ed
