How to start imaging with CW up?


Wayne Hixson
 

Still Trying to understand meridian limits and their effect on GO TO s. I’ve mapped east and west meridian limits (which are different). I have a lot of opportunity to start with the scope on east side of pier and eliminate need to do meridian flip. I’ve turned on Enable limits and permit CW up slews on E and W sides. I do not have limit to meridian checked. I had hoped to have initial go to’s within the E limits go with CW up, but my testing doesn’t seem to do this. Can it in fact be done? Thanks

wayne


Roland Christen
 

I do it all the time with scope under the mount pointing to an object 3 or 4 hours from the zenith toward the east. As long as the scope clears the pier it works very well. I simply set a meridian delay of 3 or 4 hours east so that the scope flips sides when I enter the object in either the keypad or with SkyX. The mount will do a safety slew (which takes 2 slews with a momentary pause in between) and the scope ends up underneath the mount. You want to be there by the mount to make sure that nothing gets snagged and no possibility of collision. You don't want to do this in a remote setup or in an automated setup using 3rd party software. Too much can go wrong.
If you don't want to change the meridian delay, you can also use the command "Flip Sides". However if you do any centering using co-ordinate commands (example MaximDL moves) then the scope will flip back to the original side. Keypad button moves, as well as APCC, SkyX button moves, all work fine.

Rolando

-----Original Message-----
From: Wayne Hixson via groups.io <wayneh9026@...>
To: main@ap-gto.groups.io
Sent: Tue, Apr 12, 2022 2:20 pm
Subject: [ap-gto] How to start imaging with CW up?

Still Trying to understand meridian limits and their effect on GO TO s. I’ve mapped east and west meridian limits (which are different). I have a lot of opportunity to start with the scope on east side of pier and eliminate need to do meridian flip. I’ve turned on Enable limits and permit CW up slews on E and W sides. I do not have limit to meridian checked. I had hoped to have initial go to’s within the E limits go with CW up, but my testing doesn’t seem to do this. Can it in fact be done? Thanks

wayne

--
Roland Christen
Astro-Physics


Terri Zittritsch
 

I hope you figure it out because I'll piggyback on that knowledge.    This is one topic that has eluded me and given it's easy to deal with flipped images and re-centering I haven't found it too big a deal not to figure it out.   But once in a while, I'd like to do it but haven't gotten the right formula down yet.    I always use SGP, and precise centering/solving, so maybe this further complicates things.

Terri


Worsel
 

Wayne, Terry

I use Roland's approach all the time for CW up with the OTA pointed east.  I cannot remember the last time I had to do a meridian flip in the middle of an imaging sequence.

The only thing different from normal CW down procedure is to set the meridian limit far enough east that the target object is west of the limit.  The Telescope Position diagram in APCC Meridian Tab is handy for this. 

You can either slew to the target in normal CW up, then change the meridian limit, and immediately re-slew to the same target (a flip will happen) OR change the limit first, then slew (no flip).

You may have read this already, but the section in the manual on Meridian Limits (6.16) is very helpful to understand the difference between West limits and East Limits. 

In my experience, plate-solving for centering an object works fine even in CW up configuration, because of the meridian limit.

When I was still using SGP, it seemed to do OK with CW up slews and solving, but it has been a while, so YMMV.

Bryan


Wayne Hixson
 

Thanks Brian, I’m going to try some dry runs today if it doesn’t rain. I’m using NINA right now and it doesn’t like early flips but if I start in CW up I don’t think it has a problem. What capture SW are you using now, if you don’t mind my asking?


Steven Panish
 

I almost always use +3 on the meridian delay and virtually never have to flip.
Steve

On Wed, Apr 13, 2022 at 1:19 PM Wayne Hixson via groups.io <wayneh9026=yahoo.com@groups.io> wrote:
Thanks Brian, I’m going to try some dry runs today if it doesn’t rain. I’m using NINA right now and it doesn’t like early flips but if I start in CW up I don’t think it has a problem. What capture SW are you using now, if you don’t mind my asking?



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Worsel
 

Wayne

I split up the various functions...it's easier to sort out issues then (which I rarely have anymore...mostly due to the 1100 GT mount!)

  • Capture software - SharpCap for astro CMOS,  BYEOS for Canon DSLR
  • GoTo software - Cartes du Ciel via ASCOM to the A-P ASCOM Driver
  • Plate-solving - Astrotortilla (front end GUI for astrometry.net).  Also, ASTAP
  • Guiding - PHD2, but also can go unguided with the APPC/APPM model approach, when imaging wide-field
I have NINA installed and it works fine, but I am so comfortable with the split function approach that I have not taken the time to learn NINA well.

Bryan


Worsel
 

"(which I rarely have anymore...mostly due to the 1100 GT mount!)"

VERY poorly worded.  I meant I have few problems, because the 1100 is so reiable!!  Sorry.

Bryan


Emilio J. Robau, P.E.
 

You guys get a lot more east than I do.   Plus, I am tempted but get rather paranoid since my mount is in the observatory and I run it from my upstairs office in the house.  I rarely go more than an hour and 15 minutes to the east but even that is very beneficial and when I do it, I am there for the initial slew as Roland has recommended.   I envy 3 to 4 hours!


Worsel
 

Emilio

I also control from my office in the house.  I did two things to make my self comfortable with this.

1.  I released the clutches and moved the mount through ALL positions (even beyond horizon limits) to ensure nothing (OTA, cameras, etc) can strike the pier, even during a slew.  When I make any changes to optical train, I re-do this exercise.

2. Installed a camera in the observatory.  I can pan the camera around to view the mount, the OTA, the sky above etc.  Many of us have cameras for this and other purposes.


Bryan


skester@...
 

I'm confused on this now.  If you are using APPC (with meridian limits defined and 'CW-UP' East slews checked) to run the mount and not just the ASCOM driver, do you still need to use the meridian delay feature to initiate a CW-UP slew?  This quote from the APCC-Pro help file/users manual states that slews within East limits will 'automatically' end in a CW-UP position.  Is that correct or not?  If the scope is initialized from say Park 3, and an initial slew within east limits is commanded, which side of the pier will the scope goto?

  • "When east limits are properly configured and employed, slews to targets within the east limits will automatically be made using meridian advance and APCC's safety slew logic to place the system in a counterweight-up position with the scope on the east for uninterrupted imaging through the meridian. The safety slew logic ensures that all mount movement with the counterweight up is with the RA only.

    Using the East Limits, the scope can image through the meridian and on for another 6 hours before the telescope reaches the horizon. See: Counterweight Up Slews within: East Limits below"


Marcelo Figueroa
 

This would make a fantastic tutorial for the youtube channel. I've always been intrigued by this feature of AP mounts, but the very idea of trying it makes me panic.


David Johnson
 

Definitely not a tutorial, but this is what non-flip tracking looks like for those who haven’t seen it.  This was done with SGP, but, honestly, I usually just do the meridian flip.


Ray Gralak
 

I created a short video a few years ago that shows how you would set up APCC to start counterweight-up from the East:

https://www.youtube.com/watch?v=eBUj1WgFf3k

-Ray