Mach2 first ligth - meridian limits and NINA #Mach2GTO


Andrew Burwell
 

I've finally got a clear night after owning the Mach2 a few weeks. I have tested control indoors, but not much else.

It's outside and polar aligned (via Polemaster). 

I'm on target and shooting 5 minute subs.

In NINA I have Meridian flip settings as follows: Minutes after meridian 3, Max Minutes after meridian 10. Use telescope side of pier, and recenter after flip.

In APCC I have the following settings. Enable Meridian Tracking Limits, Just warn when reaching limit. I have no counterweight up settings and no east/west limits set.

The time before limit shown looks correct as to when I expect the target to hit the meridian. I would assume it will track to the limit, warn me and keep tracking. Nina will issue a slew command between 3 and 10 minutes after the meridian, it should flip, and all should be well.

Does that sound correct? Do I need to set anything else?


ap@CaptivePhotons.com
 

On Mon, Nov 7, 2022 at 10:00 PM, Andrew Burwell wrote:
In NINA I have Meridian flip settings as follows: Minutes after meridian 3, Max Minutes after meridian 10. Use telescope side of pier, and recenter after flip.
There's also a pause before, if you want to image through the meridian (finishing the one in progress) that needs to be zero in NINA. 


Andrew Burwell
 

Thanks. I had it set to 1, it's now set to 0.


ap@CaptivePhotons.com
 

On Mon, Nov 7, 2022 at 10:39 PM, Andrew Burwell wrote:
Thanks. I had it set to 1, it's now set to 0.
One (or any positive number) will work, but NINA will stop imaging so that it can stop tracking 1 minute before meridian, and just sit and wait until the time past then do the flip.  So it should have worked, but it sounds like you are trying to have it keep imaging slightly past, then flip so there is no lost time.

The downside of that is if anything goes wrong it just keeps going counterweight up, since you have no limits set. The upside is you don't have to try to figure out the somewhat arcane way limits are put in (though there are several places it is documented, I just had trouble getting my head around negatives vs positives and pierside east vs east limits, etc.

Linwood


Andrew Burwell
 

I'm right there with you. I'm having trouble wrapping my head around the same thing. I just want the thing to flip a few minutes after the meridian. I don't need to image upside down. :-) 

I might actually set it to stop again at 1. It's not a prerequisite that I image past the meridian. I just want it to stop at some point very close, let the object pass the meridian then slew to it again with the flip.

-Andrew


ap@CaptivePhotons.com
 

On Mon, Nov 7, 2022 at 10:54 PM, Andrew Burwell wrote:
I might actually set it to stop again at 1. It's not a prerequisite that I image past the meridian. I just want it to stop at some point very close, let the object pass the meridian then slew to it again with the flip.
I ran for months with NINA set to flip at 1, and APCC set with Limit to meridian" and top stop at meridian because it seemed safer.  And it worked every time.  I finally got some limits that work -- I think.  But we are talking only one, at most 2 images you lose by having it stop a tad early and wait.  At least for me.  If you are doing 20 minute images ... well, that's a bit different.  Mine are usually 2-5 min. 

Linwood


Patrick Sparkman
 

You don't need to go to extremes with counter weight up to take advantage of this feature for efficiency and safety.  I have my Meridian settings in APCC set to a straight 45 minutes past the meridian, then set Nina to go a max of 35 minutes before invoking a flip.  My telescope hardware can safely go almost two hours past the meridian at the worst case condition, so 45 minutes as a safety stop is quite conservative.  This approach has worked perfectly for the last year, and every pier flip has been perfect with both of my AP mounts even with 20 minute exposures (which I don't really do, but tested them)

 

 

BTW - Welcome to the AP family Andrew.  I enjoy following your blog...assuming you are "that" Andrew Burwell


Andrew Burwell
 

Hey Patrick Thanks for the info! I do have a website MacObservatory.com hopefully that's the one. :) 

Last night was not a complete success with the meridian flip. APCC seemed to think the meridian was 6 minutes before the object being tracked actually got there. I checked the clock time in the AP driver and it's correct. NINA issued a GOTO command and the mount didn't move. But it plate solved and saw that it was slightly off target, so initiated a slew which at this point the object had then passed the meridian, and the flip then occurred. I did just get an MGBox, so maybe I'll hook it up tonight and pull location/time data off the GPS instead of what I initially plugged in. 

What would cause APCC to think the meridian was 6 minutes before the object gets there?