Re: Meridian management

Dale Ghent

Hi Kevin,

As others have pointed out, you manage this by specifying a slightly wider "window" of flip time in your sequencing app so that it orchestrates the flip prior to the driver's programmed limits being hit and it either stop tracking or initiating another response, usually one that is incompatible with your imaging ;) In this case, you can think of the driver being a safety stop for your mount - if the sequencer fails to do the flip for some reason, the driver will force it when the mount sails into its limits there.

Amongst the NINA devs, we have been toying around lately with the idea of meridian and horizon limits, a la what you would find in APCC. I think this kind of tight integration between mount driver and sequencing app is important. In the case of horizon limits, it would allow the sequencer to manage a "gappy" session for a target. This is useful in the cases where the target might be obstructed temporarily by a tall tree or other object and guiding and imaging must be suspended while the object is occluded, or if you want to image something up from or down to the horizon, but the horizon line at your site is very irregular. In the case of meridian limits, the app would be able to optimize exposure times around the meridian based on the clearance map that was specified, allowing a flip to be done within a varying window of space rather than a hard set limit no matter which orientation the OTA is in.

This is all in the conceptual phase at the moment, but once a design is settled on, I would like to be able to get APCC hooked into that, via published API or other means. We'll see what the future brings once we all figure it out :)

On Dec 5, 2020, at 09:41, KHursh via <> wrote:

I now have my Mach2 humming along pretty well. I have set up APPC Pro with horizons and meridians and a pointing and tracking model. Where I am stuck is with meridian behavior. I know that my mount can handle tracking past the meridian up to a point depending on where it is relative to my safety limits. My question is, with NINA or even SGPro, I have to tell the software, how long past the meridian to wait to flip so how do I predict this based on the Dec position of object I am imaging? Am I overthinking this? Should I just pick a relatively safe time, like 45 minutes, and flip there for all objects? TIA


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