Ahhh thankyou Peter

I'd doubt the slight divisor "point error" would cause it to lag that much

Cheers
--
Brendan

On Fri, Jun 25, 2021 at 07:28 PM, Ray Gralak wrote:

This slight difference in RA tracking divisor should not cause much drift. Something else is likely wrong.

Ray,

Any thoughts what it could be?

Peter

On Fri, Jun 25, 2021 at 04:51 PM, Brendan Smith wrote:

Ummm My calc's for the tracking divisor are different:
RA divisor = (1,500,000/prescaler)/(steps per rev/worm period)

Steps per rev = 256 x 125 = 32,000

Its a G11 isn't it??? Thus worm period is the same 239.344658
Pre-scaler = 1
Steps per worm revolution = 32,000

Thus Ra divisor = ((1,500,000/1)(/32,000/239.344658)) = 11,219.2??? This is my figure?

Even if its a Titian I get 14959......

I'm confused about how you got a Ra divisor of 89754

Brenden,

You had me going there for a while. That number I believe is for Gemini 1. For Gemini II with the gearbox set at 25:1 the divisor is 448771, which I then divided by 5 for the 125:1 gearbox, which give you 89754.2. The controller automatically puts in these numbers.?

Peter

My only though right now is the RA tracking divisor of 89754 ought to be 89754.2. If you let
the mount track for a couple of hours the mount does fall behind quite a bit.

This slight difference in RA tracking divisor should not cause much drift. Something else is likely wrong.

-Ray

-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf Of pcboreland via groups.io
Sent: Friday, June 25, 2021 3:14 PM
To: [email protected]
Subject: Re: [Losmandy_users_io] Changing the servo motor encoders from 256 to 512 or 1024. Any reason not
to do this?

On Thu, Jun 24, 2021 at 05:34 AM, Ray Gralak wrote:
Ray,



1. Either your graph is incorrect, or PEC is introducing a lot of drift. By the end of the worm cycle the
accumulated PEC value should be 0 (but it's not).

I tried numerous times last night to create a PEC curve that starts and ends at zero or the same point. If you try to
use any curve that does not you will of coarse get a sudden jump in guiding so they are not usable and one has to
keep PEC turned off. My only though right now is the RA tracking divisor of 89754 ought to be 89754.2. If you let
the mount track for a couple of hours the mount does fall behind quite a bit. This problem will apply to any gearbox
ratio other than 25:1. The only solution that I can see is to download the PEC curve and not use Gemini II to
calculate it.

Peter

开云体育

Ummm My calc's for the tracking divisor are different:
RA divisor = (1,500,000/prescaler)/(steps per rev/worm period)

Steps per rev = 256 x 125 = 32,000

Its a G11 isn't it??? Thus worm period is the same 239.344658
Pre-scaler = 1
Steps per worm revolution = 32,000

Thus Ra divisor = ((1,500,000/1)(/32,000/239.344658)) = 11,219.2??? This is my figure?

Even if its a Titian I get 14959......

I'm confused about how you got a Ra divisor of 89754

--
Brendan

On Thu, Jun 24, 2021 at 05:34 AM, Ray Gralak wrote:
Ray,

1. Either your graph is incorrect, or PEC is introducing a lot of drift. By the end of the worm cycle the accumulated PEC value should be 0 (but it's not).

I tried numerous times last night to create a PEC curve that starts and ends at zero or the same point. If you try to use any curve that does not you will of coarse get a sudden jump in guiding so they are not usable and one has to keep PEC turned off.? My only though right now is the RA tracking divisor of 89754 ought to be 89754.2. If you let the mount track for a couple of hours the mount does fall behind quite a bit. This problem will apply to any gearbox ratio other than 25:1. The only solution that I can see is? to download the PEC curve and not use Gemini II to calculate it.

Peter

Hello,

I am moving for work and need to lighten my load a bit. I have a losmandy gm8 with some extras for sale if anyone here is interested or might know someone who would be. I'm in Southern California for any local purchase possibilities - posted on astromart here -https://astromart.com/classifieds/astromart-classifieds/mounts-equatorial/show/losmandy-gm8g-w-polemaster-and-lw-tripod-w-scoperoller-wheels

Thanks,
deke

Indeed, thank you. I did not even realize there were two ways to align it.
Now it lines up with the leg! It does put the alz-bolt a bit close to the bigger knobs, reducing clearance but I can definitely still adjust it!

You would likely laugh if you saw my little 60mm scope sitting on this thing :)

--

Sorry for so many questions here, but in the video you say to align a leg north, which makes absolute sense.

However, no matter how I put the mount on the tripod, it wont do that.
I notice some allen bolts around the bottom of the base - are these for aligning with the leg (i.e. loosen them all, rotate the head until if faces directly over a leg and re-tighten ?)

My mount always lines up between two legs (I have taped the ground for now to allow me to get it back in place)

Makes total sense. Wish I had ordered the altitude knobs. It didn't look like something I ought to be adjusting so I left it but now I know. Will definitely do this when I do the next alignment

Thank you so much !

Correction: *The mount will take some time to settle if the threads are NOT completely engaged.

Nick,

Just a quick suggestion: it's in Brian's video, but try rotating the altitude knob such that the telescope increases in altitude on your final adjustment.? If you are adjusting to a lower altitude, you might be floating between the threads in the altitude screw (especially if your locking screws/knobs are tight).? The mount will take some time to settle if the threads are completely engaged.

-Dwight

--

On Fri, Jun 25, 2021 at 12:00 PM, Brian Valente wrote:

I just did a video starting the polar alignment video turtorials, this included some tips here on how to iterate on tightening the bolts. Might be helpful for you?

?

Fantastic ! Listening now
I loved the other intro videos that you did - super helpful in getting me up to speed rapidly

--

Hey folks, I got my new G11 out last night (just took delivery)

Definitely worth the wait time. Everything is super solid and looks awesome

It was fairly cloudy so I was just doing initial setup.
I did notice one thing though. I use Sharpcap for PA and got an "Excellent" measurement
Then I did a quick guide assistant for a few minutes, and it reported I was around 9 mins out of PA

I slewed back to Polaris and sure enough, it was now reporting a poor/fair PA of about the same

I adjusted initially with the Aziumuth locking bolts pretty snugged down, so I doubt that made a difference. I also didn't see any instructions to lock the Alt bolt, so I just adjusted it and left it (looks like I would need an Allen wrench to do so ?)

Most of the error was in alt when I went back so I'm wondering if I need to do anything to those locking bolts?

Paul,

Yes indeed. Through Michael Herman I have communicated my thoughts and specifically what might be a bug. I'm hoping Rene will in time clarify things. It is important to know the true limits of the system and have an accurate spec.?

Peter

That's good to hear, Peter. Since the document I referenced is directly from Rene, the author of Gemini, I'd like to hear from him before making any corrections to it.

Regards,

? ? ? -Paul