Meridian Limit and Unpark Question


Joshua Hufford
 

Hello everyone, after a hiatus from imaging do to mount motor failure and just general life getting in the way I'm getting my imaging setup back up and running again. My MI-250 is now running with Pittman 9000 series servo motors instead of the stock Losmandy Gemini motors, should be a big improvement. 

First question about the meridian limit, is there a way to prevent the mount from tracking a few degrees before it hits the meridian? I tried entering a negative number in the meridian overlap setting, however it wouldn't accept it. I'd like to have my mount stop tracking three degrees before the meridian if possible. I'm guessing the Meridian Limit east and west boxes are where I would set this, but I'm not exactly sure what I need to input here. 

Also I have my park position set, however when I click UnPark I get a message saying the scope is not officially parked. Any idea why that is?

Lastly I'm running version .94N. Is this the latest version? If not what is? 

Thanks!

Josh


Don W
 

Hi Josh,
It is good to hear from you again. In answer to your question about stopping tracking before the meridian, I think the answer is NO.  Why do you want to do this - maybe there is a work-around?

The latest SiTech is 095P at:
http://siderealtechnology.com/SiTechSetup095P.exe

SiTech records a note in the SiTech.cfg file about the park situation.  All that is - is a 0 for not parked and a 1 for parked.  when you start up SiTechexe, it simply reads that cfg file entry, but that really doesn't do anything.  If the mount is in your park position, then go ahead and UNPARK.

Don W


Joshua Hufford
 

Hi Don, I'm using a longer scope now that I was previously, and with my large 8 position filter wheel if I track all the way to the meridian my wiring gets awfully tight at the pier, might have to figure out something different, however a 3 degree limit on each side gives a decent amount of a safe zone. 

Thanks for the explanation of the Park, it seemed to work fine. I just didn't remember getting that message before. 

Looking forward to hopefully posting some new images soon. 

Josh

On Sun, Apr 11, 2021 at 2:21 AM Don W <westergren@...> wrote:
Hi Josh,
It is good to hear from you again. In answer to your question about stopping tracking before the meridian, I think the answer is NO.  Why do you want to do this - maybe there is a work-around?

The latest SiTech is 095P at:
http://siderealtechnology.com/SiTechSetup095P.exe

SiTech records a note in the SiTech.cfg file about the park situation.  All that is - is a 0 for not parked and a 1 for parked.  when you start up SiTechexe, it simply reads that cfg file entry, but that really doesn't do anything.  If the mount is in your park position, then go ahead and UNPARK.

Don W


MartinC
 

Hi Josh,

I don't mean to intrude but I'm currently looking at a different issue I have with Meridian limits - hence my interest in your question.

I believe you can stop your tracking before the meridian. I have just tried it on my mount.

Since version 95M you have the ability to set the meridian limits anywhere, pos or neg. You can also set the tack past limit to any positive number but not negative.

So I've set mine as per the attched images & it works. I'm sure you can experiment to suit your exact needs. I've not tried for Under the pole but I gues the same will apply.

Hope this helps

Best wishes
Martin


Don W
 

Hi Josh and Martin,

Yes, I see that 095P does allow negative limits.  I just tried setting the West limit to -5 degrees, and the mount stops tracking at 5 degrees before the meridian.

Josh this is your answer - it works!

Thanks Martin for trying this.

Don W


MartinC
 

No problem, it was good that there was a solution.

Best wishes
Martin


Joshua Hufford
 

Thanks everyone. 

So if I understand it correctly, if I want the mount to stay 3 degrees away from the meridian on both sides all the way from north to south I would set the over the pole east and west limit to -03:00:00 and the under the pole to -177:00:00

Correct?

Was clear last night and able to do some testing for the first time under stars, pointing and tracking was pretty good. With no point model all objects across the sky were within at most 2/3 from center of a 910mm scope and 8300 chip. A rough measurement of the PE looks like about 12 arc seconds peak to peak. Seeing was not too good so I couldn't really nail down the guide settings but I was able to guide long enough to get good stars at 10 minutes of exposure. 

Next clear night I'm going to work on getting a point model created and hopefully refine the guider settings. 

Josh

On Sun, Apr 11, 2021 at 6:07 PM MartinC via groups.io <mncrane=virginmedia.com@groups.io> wrote:
No problem, it was good that there was a solution.

Best wishes
Martin


Don W
 

Hi Josh,

I am finding out that 095P has some weird response to setting negative limits.  So be very careful with your settings and check those settings after you close ChangeConfig by opening ChangeConfig again.

When I set the West limit to -03:00:00, my East limit sets to -04:00:00 automatically (I can't change it).  With GEM Auto Flip Track unchecked, the mount will track to that -3 degree setting and stop.  This is what you want.

With GEM Auto Flip Go To checked, the mount will flip if you choose a target at less than 3 degrees EAST of the meridian.  I think you don't want that, so you just have to be careful.  You will control where the mount goes with GOTO's to avoid the ±3 degrees of the meridian.

I think this all will work for you, since you only track east to west (above the pole).

Good luck,
Don W

All of this is with the setting for Track Past Meridian Overlap set to zero.  If you don't have that = zero, then your mount will track past your -3 degrees.


Joshua Hufford
 

Thanks for the info Don, I'll post an update after I try this out. 

Josh

On Mon, Apr 12, 2021 at 12:00 PM Don W <westergren@...> wrote:
Hi Josh,

I am finding out that 095P has some weird response to setting negative limits.  So be very careful with your settings and check those settings after you close ChangeConfig by opening ChangeConfig again.

When I set the West limit to -03:00:00, my East limit sets to -04:00:00 automatically (I can't change it).  With GEM Auto Flip Track unchecked, the mount will track to that -3 degree setting and stop.  This is what you want.

With GEM Auto Flip Go To checked, the mount will flip if you choose a target at less than 3 degrees EAST of the meridian.  I think you don't want that, so you just have to be careful.  You will control where the mount goes with GOTO's to avoid the ±3 degrees of the meridian.

I think this all will work for you, since you only track east to west (above the pole).

Good luck,
Don W

All of this is with the setting for Track Past Meridian Overlap set to zero.  If you don't have that = zero, then your mount will track past your -3 degrees.