Re: Dec Arc APPM mode: any l best practices for field set up


 

Hey Sébastien - just one thing I can comment on:

>>>If so, I was wondering if I should ONLY tick the "Enable Dec Arc Tracking" checkbox or if I do also need to tick the "Enable Tracking Correction" box for the Dec Arc tracking corrections to be actually sent to the mount ?

Dec Arc Tracking is a type of tracking enhancement, so you definitely need to enable tracking correction regardless of whether you use dec arc or not. Then in your case enable dec arc tracking, assuming that is your preferred approach. If you disable tracking correction, no tracking corrections are applied at all

>>>

On Thu, Sep 30, 2021 at 1:21 PM Seb@stro <sebastiendore1@...> wrote:
Hello Howard,

I'm also trying to learn the ropes of the new Dec Arc Tracking feature for portable use (with a new model each night). Please keep in mind I'm totally new at modeling in general. At this point, I believe I have quite managed to understand the global idea from the a little experimentation (did a complete Dec Arc mapping run successfully), reading the manual and some recent posts but I'm still left with the following questions about the pointing model tab in APCC.

My general understanding is that the tracking corrections will use the "all-sky algorithm" to compute the correction terms from the mapped points unless the Dec Arc Tracking is also enabled in which case another algorithm (taking also other variables into account) to compute more accurately the correction terms for the current declination arc. Am I getting this right ? 

If so, I was wondering if I should ONLY tick the "Enable Dec Arc Tracking" checkbox or if I do also need to tick the "Enable Tracking Correction" box for the Dec Arc tracking corrections to be actually sent to the mount ? It seems the latter is required from what I see in the Tracking Status window, but I would like a confirmation that both types of corrections are not conflicting with each other, meaning that it is the Dec Arc algorithm that is actually the one being used to compute the tracking corrections.

Also, would you recommend to "Enable Pointing Correction" in such a case? Maybe since the model is generally rather small (< 50 pts) the pointing corrections would not be accurate enough across the sky ? Would it harm to keep the pointing corrections enabled anyway in case I would like to switch target in the same declination range for example ? What about a target outside of the "dec arc model" range?

Thanks for your time,
Sébastien




De : main@ap-gto.groups.io <main@ap-gto.groups.io> de la part de Howard Hedlund <howard@...>
Envoyé : 30 septembre 2021 12:50
À : main@ap-gto.groups.io <main@ap-gto.groups.io>
Objet : Re: [ap-gto] Dec Arc APPM mode: any l best practices for field set up
 

Hi Andrea, for portable setups, the APCC Dec Arc feature is amazing!  It is perfect for your situation. 

 

I would definitely run 3 arcs if you can spare the time – one right on the target declination, and two more – one a couple degrees north, and the other a couple degrees south of your target dec. 

 

As for the RA density, I would experiment a little.  You presently do 2 arcs each with 10 or so points giving 20 total.  3 arcs totaling between 25 and 30 should rock!

 

Mag. 7 or Better Skies!

 

Howard Hedlund

Astro-Physics, Inc.

AP Phone: 815-282-1513

Direct Phone:  815-315-7015

www.astro-physics.com

Please include this e-mail with your response.

 

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From: main@ap-gto.groups.io <main@ap-gto.groups.io> On Behalf Of Andrea Lucchetti
Sent: Thursday, September 30, 2021 6:16
To: main@ap-gto.groups.io
Subject: [ap-gto] Dec Arc APPM mode: any l best practices for field set up

 

Hi, the new functionality is now more mature and I assume some of you have some good data to share.

I usually shoot one subject per night.
Given the declination, what is the best combination of :

-number of dec arcs
-total number of points
-RA spacing

my present strategy is to run 2 arcs one degree north /south of the object declination for a total of 20 points.
But I wonder if there is a better approach. I think I can increase the number of total points while still investing a reasonable amount of time.
it is better to increase the number of points in the two arcs or may be have one middle arc running on the object declination?

Also, Someone recommended a new feature to easily model these points: I think that it would be very useful for people with a nomad set up.

Thank you,
Andrea



--
Brian 



Brian Valente

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