Re: AP1600 and Lunar Tracking Rate

Jack Huerkamp



Thank you.  The East-West tracking was pretty good while in lunar rate.  So I guess Lunar Rate was controlling RA pretty well.  The major drift was in the north-south axes, and that was probably due to the low altitude and atmospheric aberration.  When I started, the Moon was only 18 degrees up in the southeast, and by totality it about 30 degrees up.


Yours truly,




Jack Huerkamp

Jack's Astro Accessories, LLC

38388 Pine Street

Pearl River, LA 70452-5192



30.37N  89.76W


All of us get lost in the darkness.
Dreamers learn to steer by the stars.

………………………………….Neil Peart




From: <> On Behalf Of Konstantin v. Poschinger via
Sent: Monday, May 16, 2022 4:41 AM
Subject: Re: [ap-gto] AP1600 and Lunar Tracking Rate


Lunar rate works only in RA. There is also the atmospheric aberration!



Von meinem iPhone gesendet

Am 16.05.2022 um 07:24 schrieb Jack Huerkamp <Mallincamusa@...>:

Tonight, I was using a 16" RC at f/6.4 with a full frame sensor to watch the eclipse.  I also had a 91mm scope riding parallel to provide a wider FOV.  In the 16", I could see about 95% of the lunar disk.  But I constantly had to move the scope in the North direction as the Moon kept dropping down in the FOV.  The mount is permanently mounted in my observatory and polar aligned.  I verified this with my PoleMaster the other night.  I know the Moon's motion varies from day to day, but I would have assumed that the lunar rate would take that into account.  Do I have to guide on a small lunar crater to keep the Moon centered in the FOV?

Jack Huerkamp


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