Re: PemPro Polar Alignment differs East to West


Ray Gralak
 

Hi Andrew,

Hi Ray. It was pretty much the same for both Alt and Az. I ran it a couple of times and some runs it showed up to a 7
arc mins difference in Az, but pretty much stayed in the 3-5 arc min range for Alt.
That may be a problem then for the refraction theory. By default PEMPro tries to account for refraction, but an East/West difference should not be evident for the Azimuth measurement. That's because the elevation of the star hardly changes during the Azimuth measurement (on East or West) and thus the refraction contribution is too small to make that much difference.

If there was a difference in the East/West refraction contribution it would most likely be in the Altitude measurement because it is usually farther away from the meridian and thus the visual elevation of the star will usually change much faster.

-Ray Gralak
Author of APCC (Astro-Physics Command Center): http://www.astro-physics.com/index.htm?products/accessories/software/apcc/apcc
Author of PEMPro: http://www.ccdware.com
Author of Astro-Physics V2 ASCOM Driver: http://www.gralak.com/apdriver
Author of PulseGuide: http://www.pulseguide.com
Author of Sigma: http://www.gralak.com/sigma


-----Original Message-----
From: ap-gto@... [mailto:ap-gto@...]
Sent: Saturday, March 3, 2018 1:25 PM
To: ap-gto@...
Subject: [ap-gto] Re: PemPro Polar Alignment differs East to West



Hi Ray. It was pretty much the same for both Alt and Az. I ran it a couple of times and some runs it showed up to a 7
arc mins difference in Az, but pretty much stayed in the 3-5 arc min range for Alt.

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