Re: APPM model how many points portable?


Roland Christen
 

Howe accurate is ASTAP? Less than 1 arc sec or?

Rolando



-----Original Message-----
From: Jim Grubb via groups.io <jimgrubb@...>
To: main@ap-gto.groups.io
Sent: Thu, Apr 22, 2021 10:34 am
Subject: Re: [ap-gto] APPM model how many points portable?

I have the 1100 with encoders and have found a very successful very quick workflow using ASTAP-SGP-APPM.  You can turn off blind solving and it will very quickly move to the next point if it fails.  This is useful as I have the same issue with my horizon map not being perfect.  When the scope is pointing at the trees or the house, it just fails and quickly moves onto the next point.  This only happens for me near the horizon.  ASTAP is by far the fastest solver I have used and usually solves in under a second so you can turn the "Max Solve Time" parameter way down and it will fail very quickly.  I currently have mine set at 10s and am sure I could lower it to 2 or 3 seconds with no issues at all.  You may need to do a blind solve when you first set up the scope before you begin the pointing run.  [Screenshot: APPM - Plate Solve Settings Page]

On to the topic of how many points.  If you are only going after one target in an evening, you can run a narrow line at the declination of the target you are going to be imaging.  I typically use two lines spaced close together.  Here is an example of an 88 point model which covers 7 degrees of declination.  I can run this model in 1/2 hour.  And this is overkill, way more points than needed.  [Screenshot: Pointmap 1 example]

If you pull back on the RA spacing and tighten up the dec so that it only runs a single line of points at the exact declination of your target, you could get this down to 27 points, which on my rig will run in about 10 minutes.  [Screenshot: Pointmap 2 example]

Good luck!
Jim

As you experiment with different spacing, you will start to get a feel for what works.

--
Roland Christen
Astro-Physics

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