AP1600 and Lunar Tracking Rate
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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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Konstantin v. Poschinger
Lunar rate works only in RA. There is also the atmospheric aberration!
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Konstantin Von meinem iPhone gesendet
Am 16.05.2022 um 07:24 schrieb Jack Huerkamp <Mallincamusa@...>:
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Konstantin,
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
Jack Huerkamp Jack's Astro Accessories, LLC 38388 Pine Street Pearl River, LA 70452-5192 985-445-5063 30.37N 89.76W
All of us get lost in the darkness. ………………………………….Neil Peart
From: main@ap-gto.groups.io <main@ap-gto.groups.io> On Behalf Of Konstantin v. Poschinger via groups.io
Sent: Monday, May 16, 2022 4:41 AM To: main@ap-gto.groups.io Subject: Re: [ap-gto] AP1600 and Lunar Tracking Rate
Lunar rate works only in RA. There is also the atmospheric aberration!
Konstantin Von meinem iPhone gesendet
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The lunar rate in the mount is the average rate. The moon has some variability in it's rate that can be noticeable vis-a-vis the average rate. Luna also varies a bit in declination and has a drift component from that in addition to the atmospheric refraction.
Ray's *Horizons* program, which is a part of APCC, can give you very tight lunar tracking. HKH
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Thanks Howard. I will look up that aspect of APCC PRO and try it out
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Jack
On May 16, 2022, at 11:09, Howard Hedlund <howard@...> wrote:
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Roland Christen
The Lunar rate is an average rate in RA only. You would need a custom rate for both axes to follow the Moon precisely.
Roland
-----Original Message-----
From: Jack Huerkamp <Mallincamusa@...> To: main@ap-gto.groups.io Sent: Mon, May 16, 2022 12:24 am Subject: [ap-gto] AP1600 and Lunar Tracking Rate 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 -- Roland Christen Astro-Physics
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Roland,
Thank you. I am looking at trying out APCC Horizons to see if that will help out with better lunar tracking.
Yours truly,
Jack
Jack Huerkamp Jack's Astro Accessories, LLC 38388 Pine Street Pearl River, LA 70452-5192 985-445-5063 30.37N 89.76W
All of us get lost in the darkness. ………………………………….Neil Peart
From: main@ap-gto.groups.io <main@ap-gto.groups.io> On Behalf Of Roland Christen via groups.io
Sent: Monday, May 16, 2022 1:29 PM To: main@ap-gto.groups.io Subject: Re: [ap-gto] AP1600 and Lunar Tracking Rate
The Lunar rate is an average rate in RA only. You would need a custom rate for both axes to follow the Moon precisely.
Roland
-----Original Message----- 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?
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