Levelling 119FSA for AP1100 RA base


Shailesh Trivedi
 

I am trying to mount my AP1100 GTO AE to a permanent non-AP pier for the first time.

The bubble level is a bit off-center (see attached image).

Is this a concern? Should I put shims under the 119FSA to try to center the bubble? My application is astrophotography.

Shailesh


Mike Dodd
 

On 6/8/2021 10:21 AM, Shailesh Trivedi wrote:
I am trying to mount my AP1100 GTO AE to a permanent non-AP pier for the
first time.

The bubble level is a bit off-center (see attached image).
How is the mount attached to the pier? I cast a concrete pier, then bolted an A-P SPA Standard Pier Adapter to four 5/8" threaded rods embedded in the concrete. I put nuts on the rods to allow me to adjust the level of the SPA. This photo shows the setup: <http://astronomy.mdodd.com/observatory.html#PierBolts>

Can you do something similar?

--- Mike


Shailesh Trivedi
 

Thanks for your feedback Mike. I do not have such a method. The only option I have is to put shims under the 119FSA.

Shailesh


Christopher Erickson
 

Absolutely not a concern.


-Christopher Erickson
Observatory engineer
Waikoloa, HI 96738
www.summitkinetics.com
   

On Tue, Jun 8, 2021, 4:21 AM Shailesh Trivedi <strivedi@...> wrote:
I am trying to mount my AP1100 GTO AE to a permanent non-AP pier for the first time.

The bubble level is a bit off-center (see attached image).

Is this a concern? Should I put shims under the 119FSA to try to center the bubble? My application is astrophotography.

Shailesh


Worsel
 

I recall Rod Mollise once said 'you can mount an equatorial on the side of a barn as long as the polar alignment is good.'

Bryan


Shailesh Trivedi
 

Thank you, Chris and Bryan. I got similar feedback from George at AP who also said do NOT put shims to level; perhaps some iterations needed for PA but I have to do that anyway.

Shailesh


Roland Christen
 

German equatorial mounts do not need to be level. They just need to be polar aligned, which does not require leveling.

Rolando



-----Original Message-----
From: Shailesh Trivedi <strivedi@...>
To: main@ap-gto.groups.io
Sent: Tue, Jun 8, 2021 9:21 am
Subject: [ap-gto] Levelling 119FSA for AP1100 RA base

I am trying to mount my AP1100 GTO AE to a permanent non-AP pier for the first time.

The bubble level is a bit off-center (see attached image).

Is this a concern? Should I put shims under the 119FSA to try to center the bubble? My application is astrophotography.

Shailesh

--
Roland Christen
Astro-Physics


Roland Christen
 


The only option I have is to put shims under the 119FSA.
Don't do that! You want stability, not level.

Rolando


-----Original Message-----
From: Shailesh Trivedi <strivedi@...>
To: main@ap-gto.groups.io
Sent: Tue, Jun 8, 2021 11:21 am
Subject: Re: [ap-gto] Levelling 119FSA for AP1100 RA base

Thanks for your feedback Mike. I do not have such a method. The only option I have is to put shims under the 119FSA.

Shailesh

--
Roland Christen
Astro-Physics


Christopher Erickson
 

Being reasonably-level when setting up a tripod or portable pier is good for safety reasons, of course.


-Christopher Erickson
Observatory engineer
Waikoloa, HI 96738
www.summitkinetics.com
   

On Tue, Jun 8, 2021, 10:33 AM Roland Christen via groups.io <chris1011=aol.com@groups.io> wrote:
German equatorial mounts do not need to be level. They just need to be polar aligned, which does not require leveling.

Rolando



-----Original Message-----
From: Shailesh Trivedi <strivedi@...>
To: main@ap-gto.groups.io
Sent: Tue, Jun 8, 2021 9:21 am
Subject: [ap-gto] Levelling 119FSA for AP1100 RA base

I am trying to mount my AP1100 GTO AE to a permanent non-AP pier for the first time.

The bubble level is a bit off-center (see attached image).

Is this a concern? Should I put shims under the 119FSA to try to center the bubble? My application is astrophotography.

Shailesh

--
Roland Christen
Astro-Physics


Peter Nagy
 

If you are using RAPAS, shouldn’t the mount be level in East-West direction?

Peter 


Shailesh Trivedi
 

Thank you Rolando. No shims.

Shailesh


 

If the mount is off level, it makes a small difference. Shailesh’s pier is only off by less than a degree, so his RAPAS will still be pretty accurate. I just ran the numbers and if the RAPAS reticle is off level by 1 degree, aligning would result in a .7 arcmin error max from the misalignment alone. Not enough to cause a significant error, or be noticeable over the alignment error caused by human eyes using the RAPAS.  If the pier was off by 5 or 6 degrees there would be more concerns than just the RAPAS.

 

Liam

 

From: main@ap-gto.groups.io <main@ap-gto.groups.io> On Behalf Of Peter Nagy
Sent: Tuesday, June 8, 2021 3:58 PM
To: main@ap-gto.groups.io
Subject: Re: [ap-gto] Levelling 119FSA for AP1100 RA base

 

If you are using RAPAS, shouldn’t the mount be level in East-West direction?

Peter