Hi, New to SGpro I am having a rough time getting Auto Focus to work properly, my plots are all over the place.
I am using 2x Pegasus ver3 motor focusers in my setup.
Please can someone advise:
a. in my focuser “settings” I have selected and set a value (95) for backlash compensation. Then in “other” I have also selected “focuser backlash compensation” and selected “compensation direction” IN and value (95 which is the value of backlash I have measured in my focuser train). Is this correct or am I introducing 2 lots of compensation?
b. Within Auto focus settings I have set a step size of 25, is this too small?
I use a Pegasus. I don’t think you are adding two lots of backlash compensation. However, if you’ve measured your backlash to be 95 steps then I would suggest you set the amount to around 130 - you always want to have a bit more than the measured amount to make sure you get the full effect of compensation. As for your step size, you can’t use an arbitrary figure (which I’m presuming 25 is). You need to set your number of steps and your step size according to a very specific procedure which is well explained in the manual under ‘understanding autofocus’ here http://mainsequencesoftware.com/content/Sequence%20Generator%20Pro.pdf page 124. Good luck.
Having adjusted the auto focus step size in accordance with the manuals’ guidance, I observed approximate V shapped plots on both of my systems albeit with a couple of outliners. Now I am confused, last night I attempted different target SGP captures on both systems and rather than a vertical V plot during auto focus both plots appeared to be almost horizontal.
Anybody experienced this themselves.
Screenshots of your plots would be useful, both the “approximate V …” and the “almost horizontal”. The latter suggests the HFR isn’t changing as the focuser moves so simple things to check are, 1) is the focuser moving, 2) since you have moved to a new target have you started your autofocus run from a good focus point. Also, what optical gear are you using?
A flat curve suggested you haven’t set your step size correctly. I have produced a basic video here which may help.
As noted above, your backlash compensation can be higher but not lower than your actual backlash. On the Pegasus this number is usually quite high as they are quite high resolution. Input a high number then fine tune it down at a later stage.
make sure you have sufficient exposure. If you are coming from something like FocusMax, that system uses a single bright star with very short exposure times. My exposures with a 250mm f/8 scope and Lodestar are about 8 seconds.
Thanks RayD, your video was invaluable to someone like me who is new to SGP. I used the control panel to change settings which weren’t saved in my profile.
Thanks Buggs, I clearly had my exposures too short which resulted in fewer stars, many of which were in the lower 3rd of my image.
Next clear night I hope to measure and prove both systems.