Re: OnStep G11 First Light - 119 Second PE?
|
Hi Tony
i have just a couple observations for you - sounds like you have a good handle on things so just the highlights:
- your long guiding run looks quite good. RA and DEC seem to have a lot of movement in common, which makes me think it's either a calibration orthagonality issue (which it isn't based on your calibration run) or perhaps something is slightly slipping or rotating in your guide setup
- your min moves might be a bit high, there's a lot of wandering about in there.?
you might do a Guiding Assistant run here for recommendations as well as measuring your polar alignment, which seems a bit off as well
- i would increase your backlash compensation max move to 1500.?
- definitely see what you can do about that 2x error. You can also use PPEC and target that period directly, but it's easier and more effective to do mechanically
Your dad is awesome, I think you are doing processing for him? some pretty impressive stuff so far
On Sun, May 2, 2021 at 3:59 PM GuitsBoy < guitsboy@...> wrote:
Hi Brian -
Thanks for your response.? Since you asked, I will provide the
logs, however your time would certainly be better spent helping
others who have already reached the end of their own
troubleshooting.? I certainly dont want to take time away from
those would could really use you.? Like my Dad. :)? This was
merely a shakedown run, and I haven't had a chance to do any
tweaking yet.? With the clouds, I wasn't expecting much.? I didnt
even run the calibration in a suitable location,? and I didnt
bother running the guiding assistant yet.? When I get some better
conditions, I certainly will, but this was just to get a quick and
dirty baseline.
Thanks for your document.? I'm familiar with just about all of
the stuff you cover in there.? Most of which, I knowingly skipped
over or cheated in the interest of beating the heavy clouds.?
Since the final gearing ratio of the direct drive G11 (1:360) is
reasonably close to my meade LXD650 (1:405) I reused many of the
settings and tactics that I learned over the last year with the
meade.? Again, willfully cheating in the interest of time.
As for PEC prep, I'm not using it in the normal way.? I'm simply
using it as a tool to show the period of the error while guiding,
since visually, you can see its very regular.? I just wanted it to
clue me in on where the error resides in relation to the worm
period.? While yes, some of the guide error is reactionary in
nature, there still must be a regularly occurring glitch in the
drivetrain.? At 120 seconds, I have to suspect the coupler.? Had
it been 240 or 75 seconds, Id suspect the worm or bearings.? Could
still be, but for now, I switched out the rigid coupler to a
flexible helical coupler to see if things improve next time.
Please don't spend any time analyzing some quick and dirty logs
from an unfamiliar control system, especially since it was nothing
more than a test run to make sure things were working correctly.??
Truthfully, I'm already quite impressed with the mount having done
as well as it did, especially through the clouds.? Diagnosing,
tweaking and improving is all part of the fun.? I'll be sure to
run guiding assistant next time to see where the native unguided
PE lands.? Unguided performance really isn't terribly important
for me in particular.? Simply getting any abrupt drivetrain
defects down to where they can be guided around is my ultimate
goal.? I was mostly just curious if the 119-120 second periodic
error rang a bell for anyone.
Thanks again for your help and suggestions,
- (Little) Tony S
On 5/2/2021 5:01 PM, Brian Valente
wrote:
Hi Tony
Can you share the guidelogs from your screen caps?
i'm assuming if you have not yet done the unguided output, the
PECPrep is a residual error, and not the raw periodic error of the
mount
I have seen the 2x be a function of the coupler. It could be
slightly off-kilter but if you've moved to the oldham, it would be
the same thing. You can try to measure the distance between the
coupler and the plate beneath it using an improvised measurement
(like a hex wrench or stick) and just make sure it's consistent
all the way across?
Getting a solid 30-45 minute unguided run from guiding assistant
in PHD is a great idea (i recommend the latest 2.6.9 dev 4
release). Here are steps for a baseline guiding which I always
recommend people start with to eliminate a lot of inadvertent
variables in the setup
Brian
-- Brian?
Brian Valente portfolio
|
