Re: AP1200 GTO and backlash in its brass gear?
Hi Konstantin,toggle quoted message Show quoted text
>>have ever tried and set a backslash time other than 0?
Nope, because in my discussions with AP support they always sais that I should remove any backlash setup from GTOCP3 and do the same also for PEC (disable those). I personally think too, that it would be best to get tracking as good as it gets without any additional backlash compensation. And then (after this, if it is still required) setup backlash timing accordingly. This is a sort of perfectionist / purist way of doing setup, which I'm trying to follow here.
I would like to know how much AP1200 backlash should I tolerate? What is the normal amount of backlash for a well tuned AP1200 mount? In my mount, this amount of needed backlash compensation is quite big (=huge for an AP mount, I think). And for this reason, I should not just use backlash compensation in software or GTOCP3.
I can show you a PHD2 graph for that, where I have used PHD2's Guiding Assistant recommendations:
Normally you can get away with 50ms pulses in DEC guiding and then you need 1800 ms guide pulse for switching directions, IF you let PHD2 to do its' corrections at one go. That tells me that there is something wrong in my mount with its' backlash.
Here is the same backlash thing in close-up (zoomed-in) view:
If I do not allow this 1800 ms backlash compensation in PHD2, then I will get this kind of slow drift in DEC axis: (both ways let me image with round stars)
In that image PHD2 makes a series of smaller corrections, which gradually "pulls-in" all looseness in DEC axis (=backlash) and when gears finally engage, then direction for tracking error changes (and you need to have small enough pulse into the opposite direction, so that you don't overshoot with it). And then, after this correction drift starts again. Sort of weird balance I have found from there. Anyway, my polar alignment accuracy is somewhere in 2'...4' range and guiding in one direction (N/S) only loses star permanently on the "wrong side". That happens randomly, so I prefer keep guiding in Auto mode for DEC.
My setup is in a permanent roll-of-roof observatory seen in this image:
(Don't look at the missing cable ties, this is an early image of my current setup ;)
PS. Should I delete "the tail below" from my reply into this AP group? I'm not familiar with this interface, so I need to ask :-)
---In ap-gto@..., <k.poschinger@...> wrote :
have ever tried and set a backslash time other than 0?
Konstantin v. Poschinger