Hi Gang,
One of the great new features in APCC v1.9.x is Dec Arc Tracking.  There was some discussion when v. 1.9.x was released, but there were many other subjects for discussion as well.  In the meantime, I prepared this little tome to hopefully explain it all a bit better.  Please have a look and tell me how I can improve the document.
https://ap-gto.groups.io/g/main/wiki/28325  

Hi Howard,

The document looks good to me.  I do have a question though...

I am presently running APCC v1.8.8.17.  I was reading your description of the "Dec Arc Tracking on a mini Dec-Arc-Model".  This is essentially what I have been doing for the last year and a half since I got my Mach2.  My APPM parameters are a little different - horizon limits and RA spacing - but I set up three lines with 2 or 3 degree declination spacing.  It works so well that I have lost track of where my guide scope and guide camera are stored.

I understand that the new version of APCC Pro has an "Enable Dec Arc Tracking" button somewhere [presumably in the pointing model tab].

My question is... If I upgrade to APCC Pro v1.9, what does the "Enable Dec Arc Tracking" button get me that I don't have now?  I read in the release announce by Marj that we get a "Declination-Arc tracking algorithm." and that "This new algorithm is an alternative to the normal all sky tracking model that APCC Pro uses."  However, I haven't figured out how the new algorithm improves on what I am doing now.

I'm one of those "if it isn't broke then don't fix it" adherents as far as my imaging software stack is concerned.  I have been waiting to upgrade to v1.9 and haven't really felt the need to do so since my current version is performing flawlessly.  I will upgrade if there is a performance advantage over what I am using now though.

Thanks in advance for your advice.

Dean Jacobsen
Astrobin Image Gallery - https://www.astrobin.com/users/deanjacobsen/

Hi Dean,

My question is... If I upgrade to APCC Pro v1.9, what does the "Enable Dec Arc Tracking" button get me that I
don't have now? I read in the release announce by Marj that we get a "Declination-Arc tracking algorithm." and
that "This new algorithm is an alternative to the normal all sky tracking model that APCC Pro uses." However, I
haven't figured out how the new algorithm improves on what I am doing now.

The All-Sky model calculates pointing terms that are influenced by points throughout the sky. Usually, this works well, but sometimes there are localized, unmodelled factors. The Dec Arc method makes tracking rates more accurate by mapping and modeling the errors local to the declination of a target to be imaged.

I'm one of those "if it isn't broke then don't fix it" adherents as far as my imaging software stack is concerned.
I have been waiting to upgrade to v1.9 and haven't really felt the need to do so since my current version is
performing flawlessly. I will upgrade if there is a performance advantage over what I am using now though.

You don't need to purchase a subscription renewal to download, install, and run APCC v1.9.x. The new v1.9 features, including Dec Arc tracking, are only activated if your license is dated August 1, 2020, or later, but there are bug fixes and minor improvements that make installing 1.9 worthwhile. And, if you have problems with v1.9 you can always uninstall it and reinstall v1.8.8.17.

-Ray

-----Original Message-----
From: main@ap-gto.groups.io [mailto:main@ap-gto.groups.io] On Behalf Of Dean Jacobsen
Sent: Monday, November 15, 2021 8:57 PM
To: main@ap-gto.groups.io
Subject: Re: [ap-gto] Dec Arc Tracking in APCC in our Wiki #Guiding

Hi Howard,

The document looks good to me. I do have a question though...

I am presently running APCC v1.8.8.17. I was reading your description of the "Dec Arc Tracking on a mini
Dec-Arc-Model". This is essentially what I have been doing for the last year and a half since I got my Mach2.
My APPM parameters are a little different - horizon limits and RA spacing - but I set up three lines with 2 or 3
degree declination spacing. It works so well that I have lost track of where my guide scope and guide camera
are stored.

I understand that the new version of APCC Pro has an "Enable Dec Arc Tracking" button somewhere
[presumably in the pointing model tab].

My question is... If I upgrade to APCC Pro v1.9, what does the "Enable Dec Arc Tracking" button get me that I
don't have now? I read in the release announce by Marj that we get a "Declination-Arc tracking algorithm." and
that "This new algorithm is an alternative to the normal all sky tracking model that APCC Pro uses." However, I
haven't figured out how the new algorithm improves on what I am doing now.

I'm one of those "if it isn't broke then don't fix it" adherents as far as my imaging software stack is concerned.
I have been waiting to upgrade to v1.9 and haven't really felt the need to do so since my current version is
performing flawlessly. I will upgrade if there is a performance advantage over what I am using now though.

Thanks in advance for your advice.

Dean Jacobsen
Astrobin Image Gallery - https://www.astrobin.com/users/deanjacobsen/
<https://www.astrobin.com/users/deanjacobsen/>

You don't need to purchase a subscription renewal to download, install, and run APCC v1.9.x. The new v1.9
features, including Dec Arc tracking, are only activated if your license is dated August 1, 2020, or later, but
there are bug fixes and minor improvements that make installing 1.9 worthwhile.

And to be clear, you don't need to purchase a subscription renewal to get the bug fixes and minor feature improvements in 1.9. Those are free!

-Ray

Thanks for the info Ray.
--
Dean Jacobsen
Astrobin Image Gallery - https://www.astrobin.com/users/deanjacobsen/