Re: Very frustrated with my model. Errors seem very large. #Mach2GTO #Polar_Alignment

Micheal Fields Jr

Yes Ray, I am using APCC.  Can I use something else to model?  Your question seems to imply I can?  If so, can you or someone else please explain that process?  Or do you mean use the hand controller to manually align?

I am nearly 100% positive I have the latest ascom SP1.  Not only do I keep it up to date but I also did a "check for updates" from the ascom folder and it reported no new updates available.  What I can try is to uninstall it clean and do a fresh install.  I keep a portable hard drive with all the latest revisions of all my drivers and software but when I am too lazy to find it I typically just do a re-download.   I also captured some video of these issues but it is hours long and needs to be edited down to something worth a watch.  Was up until 4am fighting with this so the 4 hours of sleep I am on now means I may not get anything accomplished today.

On Thu, Jan 7, 2021 at 07:29 AM, Ray Gralak wrote:
Hi Michael,

Although you don't specifically mention APCC, I assume that is what you are using for a model?

If so, the behavior you are describing sounds like you may be running the ASCOM Platform 6.5 with the "Transform" bug. APPM and APCC use the ASCOM Transform class to convert plate-solved J2000 coordinates to the current epoch. The severe bug in this version of ASCOM makes the Transform class un-reusable, so all follow-up J2000 transformations return the same RA,Dec coordinate pair as the first, and thus results a bad model.

I suggest you download and install ASCOM Platform 6.5 SP1 from the ASCOM web site. Unfortunately you will have to use APPM to collect data points again.

-Ray Gralak
Author of PEMPro
Author of APCC (Astro-Physics Command Center):
Author of Astro-Physics V2 ASCOM Driver:

-----Original Message-----
From: [] On Behalf Of Micheal Fields Jr via
Sent: Thursday, January 7, 2021 3:15 AM
Subject: [ap-gto] Very frustrated with my model. Errors seem very large. #Mach2GTO #Polar_Alignment

Used the QHY Polemax camera and software to dial in the polar alignment which seemed pretty straight forward.
Should be right on the money.

Then I also happen to have the MGbox and that is connected providing temp, pressure, humidity and GPS.

I am running a piece of software on my computer called Dimension4 which communicates with all the atomic
clocks all over the world and gets extremely precise time. I have the software choose to update time from PC as

So the polar alignment should be excellent, the time offset correction should be excellent, the gps coordinates
excellent, the weather information pretty good.

Using SGP I did a focus run prior to doing the model.

Now some details that are going against me.
The telecope is an 11" EdgeHD. I am using two dovetail bars. Both Losmandy D type with radius blocks. One on
top of the scope and one of course on the bottom. The bolts are very tight FYI.
I have the easy balance 16" saddle and it is also bolted very tightly to the mount. I double checked all bolts.

Clutches are tight, the two side knobs on the mount for elevation clutch are both tight. The three bolts from the
adapter pier plate are tight as are the bolts from that plate to the top of the tripod.

But it is an SCT. And I am focusing using the primary mirror which means it is not locked and does move around
under its own weight.

The imaging train is light weight and is all threaded connections. Nothing moves.

So I start the model and it shows me results like RA delta is -2948.643 and the dec delta is -1581.175 arc min.

When complete and I look at the "model" it shows things like 9599.37 arc-seconds East Model and 9548.46 arc-
seconds in West model. Polar axis elecation 143987.03 east and 139238.67 west. Index Error HA 230742.67
east and -225292.62 west.

What does that mean? Well I assume it means that what it wants to see and what it actually sees are very

I wonder if I am not checking the correct boxes.

Then when I am done I am seeing, based upon those high numbers, a very high number for the polar alignment
error. But I know it is correctly aligned.

Then when I am all done with the bad model and I have tracking adjustments enabled and the model enabled a 5
second image is all star trails.

So obviously everything is wrong as if it thinks the time is something it isn't or the GPS coordinates are
something they are not or it is just plate solving the wrong position?

I tried it with SGP and both Platesolve2 and ASTAP. Both yield the same issue.

Now If I just do a regular T-Point run in TSX Pro with all model stuff disabled, it seems normal and reasonable.
Since the mirror is unlocked because I focus using the primary mirror so I need to model any mirror shift/flop, The
sky RMS pointing in TSX Pro after doing a 33 point run and crunching it with a "super model" is 16.6 PSD=19.15

So my "point" hehe is that TSX T-Point doesn't seem to have any issues with dramatic errors in pointing.

So I am stumped. Why am I seeing such chaos?

If I am just throwing out a random guess that would make sense to me would be that it is not
reading/understanding the gps coordinates and elevation correctly so when it solves an image it is drastically off
from where it thinks it should be. But with a GPS connected, the MGbox, and the time synced with my PC, AND
absolute encoders, this should not ever happen.


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