APPM requirements


Ted Mickle
 

I would appreciate some guidance on how to set up APPM. I have an AP 1100GTO on an ATS pier that has been stabilized with three ratchet ropes attached to steel anchors imbedded 4 inches into a concrete slab.

I keep the mount and TAK f/7.7 TOA 130 covered with Telegizmos 365 covers when not in use.

Is this a stable enough platform to build reliable pointing models?

If so, can a reliable pointing model be obtained with illumination from the moon?

What is the maximum focal length recommended for use with APPM?

Thanks for your assistance and guidance.

Ted


Worsel
 

Ted

There have been a couple recent threads on building APPM models during bright moon times.  Here is one.  https://ap-gto.groups.io/g/main/topic/81388396

I do not think there is a max limit on focal length, as long as plate solving still functions.  I build models on a 2500 mm OTA with a full frame sensor / OAG and plate-solving is not a problem. 

Image scale may be more important.  The APPM section states
"If your image scale when binned in less than 3 arc-seconds/binned pixel then plate solve accuracy
will not be affected."



Bryan


Joseph Beyer
 

Ray has also created a YouTube video for APPM.  It’s intended for use with Sequence Generator Pro for camera control but essentially highlights the setup. Following the steps makes it quite simple. 

 

https://youtu.be/XwFbQTVIobM


Joe


Dean Jacobsen
 

Ray's APCC/APPM on-line manual is a great place to start.

https://www.siriusimaging.com/Help/APCC/index.html

There is a specific section for APPM that I used to get everything set up.
--
Dean Jacobsen
http://astrophoto.net/wp/
Image Gallery - http://astrophoto.net/wp/image-gallery/
Astrobin Image Gallery - https://www.astrobin.com/users/deanjacobsen/ 
Amateur Radio Call Sign - W6DBJ


Jeffc
 

Speaking of “requirements”…

What’s the thought on using APPM with a non-permanent setup?

Fwiw, I’m using the mach2 now with an st8300m + fs128 at about 1040mm focal length and am “visually” seeing decent round stars with 5 minute unguided exposures.   

I’ve only had the mount for a couple weeks, but I also used the 130GT at 614mm with (iirc) 20 minute exposures unguided.

Yes, objects do not land in the center of the chip on a goto , but it is usually close enough such that I can plate solve , sync , then goto again (for proper framing).

I’m guessing APPM might help with longer exposures , and also with objects low on horizon affected by atmospheric distortion… the latter would be nice to correct for.  At this point I image objects when they are fairly high on the sky.

What would be the guidelines for a “portable” setup ?  
Eg 
a) create model at the site but it could be reused for the same location?
 b) or.. it is necessary to re-create model if the mount is moved.. ie polar alignment is re-done?

I’ve just wondered about the practicality for a non-permanent setup, and the conditions where APPM is needed for unguided imaging… eg the focal length where APPM becomes effective over just the encoders on a polar aligned mount..  Or is the benefit simply repeatable pointing accuracy?

Thx


On Mar 23, 2021, at 12:39 PM, Dean Jacobsen <deanjacobsen@...> wrote:

Ray's APCC/APPM on-line manual is a great place to start.

https://www.siriusimaging.com/Help/APCC/index.html

There is a specific section for APPM that I used to get everything set up.
--
Dean Jacobsen
http://astrophoto.net/wp/
Image Gallery - http://astrophoto.net/wp/image-gallery/
Astrobin Image Gallery - https://www.astrobin.com/users/deanjacobsen/ 
Amateur Radio Call Sign - W6DBJ


Ray Gralak
 

Hi Jeff,

I’ve just wondered about the practicality for a non-permanent setup, and the conditions where APPM is needed for
unguided imaging… eg the focal length where APPM becomes effective over just the encoders on a polar aligned
mount.. Or is the benefit simply repeatable pointing accuracy?
A pointing model will improve both tracking and pointing accuracy, including accounting for drift from polar alignment error.

However, if you move the mount you will need to recreate the model from scratch, but that should not take much time. Usually, APPM will do between 2-3 points per minute, so you should easily be able to do a 50-point model (25 points per side) in about 15-25 minutes. You can do this even before the skies are completely dark, thus not losing any imaging time.

The accuracy of a model is roughly related to the square root of the number of points on each side. For example, going from 25 to 100 points per side will roughly double the tracking and pointing accuracy (because 100 is four times 25 and the square root of four is two!).

-Ray

-----Original Message-----
From: main@ap-gto.groups.io [mailto:main@ap-gto.groups.io] On Behalf Of Jeffc
Sent: Tuesday, March 23, 2021 1:54 PM
To: main@ap-gto.groups.io
Subject: Re: [ap-gto] APPM requirements

Speaking of “requirements”…

What’s the thought on using APPM with a non-permanent setup?

Fwiw, I’m using the mach2 now with an st8300m + fs128 at about 1040mm focal length and am “visually” seeing
decent round stars with 5 minute unguided exposures.

I’ve only had the mount for a couple weeks, but I also used the 130GT at 614mm with (iirc) 20 minute exposures
unguided.

Yes, objects do not land in the center of the chip on a goto , but it is usually close enough such that I can plate solve
, sync , then goto again (for proper framing).

I’m guessing APPM might help with longer exposures , and also with objects low on horizon affected by
atmospheric distortion… the latter would be nice to correct for. At this point I image objects when they are fairly
high on the sky.

What would be the guidelines for a “portable” setup ?
Eg
a) create model at the site but it could be reused for the same location?
b) or.. it is necessary to re-create model if the mount is moved.. ie polar alignment is re-done?

I’ve just wondered about the practicality for a non-permanent setup, and the conditions where APPM is needed for
unguided imaging… eg the focal length where APPM becomes effective over just the encoders on a polar aligned
mount.. Or is the benefit simply repeatable pointing accuracy?

Thx




On Mar 23, 2021, at 12:39 PM, Dean Jacobsen <deanjacobsen@outlook.com> wrote:



Ray's APCC/APPM on-line manual is a great place to start.

https://www.siriusimaging.com/Help/APCC/index.html

There is a specific section for APPM that I used to get everything set up.
--
Dean Jacobsen
http://astrophoto.net/wp/
Image Gallery - http://astrophoto.net/wp/image-gallery/
Astrobin Image Gallery - https://www.astrobin.com/users/deanjacobsen/
<https://www.astrobin.com/users/deanjacobsen/>
Amateur Radio Call Sign - W6DBJ


Jeffc
 

Thx Ray for the info... this kinda confirms what I was thinking... create a model after polar aligning.  (I just need to figure out a repeatable routine.  A project for the full moon weekend.)

-jeff

On Wed, Mar 24, 2021 at 7:39 AM Ray Gralak <iogroups@...> wrote:
Hi Jeff,

> I’ve just wondered about the practicality for a non-permanent setup, and the conditions where APPM is needed for
> unguided imaging… eg the focal length where APPM becomes effective over just the encoders on a polar aligned
> mount..  Or is the benefit simply repeatable pointing accuracy?

A pointing model will improve both tracking and pointing accuracy, including accounting for drift from polar alignment error.

However, if you move the mount you will need to recreate the model from scratch, but that should not take much time. Usually, APPM will do between 2-3 points per minute, so you should easily be able to do a 50-point model (25 points per side) in about 15-25 minutes. You can do this even before the skies are completely dark, thus not losing any imaging time.

The accuracy of a model is roughly related to the square root of the number of points on each side. For example, going from 25 to 100 points per side will roughly double the tracking and pointing accuracy (because 100 is four times 25 and the square root of four is two!).

-Ray

> -----Original Message-----
> From: main@ap-gto.groups.io [mailto:main@ap-gto.groups.io] On Behalf Of Jeffc
> Sent: Tuesday, March 23, 2021 1:54 PM
> To: main@ap-gto.groups.io
> Subject: Re: [ap-gto] APPM requirements
>
> Speaking of “requirements”…
>
> What’s the thought on using APPM with a non-permanent setup?
>
> Fwiw, I’m using the mach2 now with an st8300m + fs128 at about 1040mm focal length and am “visually” seeing
> decent round stars with 5 minute unguided exposures.
>
> I’ve only had the mount for a couple weeks, but I also used the 130GT at 614mm with (iirc) 20 minute exposures
> unguided.
>
> Yes, objects do not land in the center of the chip on a goto , but it is usually close enough such that I can plate solve
> , sync , then goto again (for proper framing).
>
> I’m guessing APPM might help with longer exposures , and also with objects low on horizon affected by
> atmospheric distortion… the latter would be nice to correct for.  At this point I image objects when they are fairly
> high on the sky.
>
> What would be the guidelines for a “portable” setup ?
> Eg
> a) create model at the site but it could be reused for the same location?
>  b) or.. it is necessary to re-create model if the mount is moved.. ie polar alignment is re-done?
>
> I’ve just wondered about the practicality for a non-permanent setup, and the conditions where APPM is needed for
> unguided imaging… eg the focal length where APPM becomes effective over just the encoders on a polar aligned
> mount..  Or is the benefit simply repeatable pointing accuracy?
>
> Thx
>
>
>
>
>       On Mar 23, 2021, at 12:39 PM, Dean Jacobsen <deanjacobsen@...> wrote:
>
>
>
>       Ray's APCC/APPM on-line manual is a great place to start.
>
>       https://www.siriusimaging.com/Help/APCC/index.html
>
>       There is a specific section for APPM that I used to get everything set up.
>       --
>       Dean Jacobsen
>       http://astrophoto.net/wp/
>       Image Gallery - http://astrophoto.net/wp/image-gallery/
>       Astrobin Image Gallery - https://www.astrobin.com/users/deanjacobsen/
> <https://www.astrobin.com/users/deanjacobsen/>
>       Amateur Radio Call Sign - W6DBJ
>
>







ap@CaptivePhotons.com
 

I use TSX tPoint now with a MyT, and anticipating the 1100 soon.

 

Does this mean that APPM does not have a concept similar to the recalibrate of TSX?

 

I have a (something like) 200 point model, but each time I set up I just run 15-20 points and it recalibrates for the new polar align (etc) and effectively shifts the prior model slightly to line up in some way.

 

It’s handy.  It can be especially handle if there are a fair number of clouds that may make it difficult to get a full model run.

 

It’s not a killer issue since generally there’s plenty of time before full-enough dark to image, but…

 

So no “recalibrate” type run in APPM?

 

 

From: main@ap-gto.groups.io [mailto:main@ap-gto.groups.io] On Behalf Of Jeffc via groups.io
Sent: Wednesday, March 24, 2021 12:26 PM
To: main@ap-gto.groups.io
Subject: Re: [ap-gto] APPM requirements

 

Thx Ray for the info... this kinda confirms what I was thinking... create a model after polar aligning.  (I just need to figure out a repeatable routine.  A project for the full moon weekend.)

 

-jeff

 

On Wed, Mar 24, 2021 at 7:39 AM Ray Gralak <iogroups@...> wrote:

Hi Jeff,

> I’ve just wondered about the practicality for a non-permanent setup, and the conditions where APPM is needed for
> unguided imaging… eg the focal length where APPM becomes effective over just the encoders on a polar aligned
> mount..  Or is the benefit simply repeatable pointing accuracy?

A pointing model will improve both tracking and pointing accuracy, including accounting for drift from polar alignment error.

However, if you move the mount you will need to recreate the model from scratch, but that should not take much time. Usually, APPM will do between 2-3 points per minute, so you should easily be able to do a 50-point model (25 points per side) in about 15-25 minutes. You can do this even before the skies are completely dark, thus not losing any imaging time.

The accuracy of a model is roughly related to the square root of the number of points on each side. For example, going from 25 to 100 points per side will roughly double the tracking and pointing accuracy (because 100 is four times 25 and the square root of four is two!).

-Ray

> -----Original Message-----
> From: main@ap-gto.groups.io [mailto:main@ap-gto.groups.io] On Behalf Of Jeffc
> Sent: Tuesday, March 23, 2021 1:54 PM
> To: main@ap-gto.groups.io
> Subject: Re: [ap-gto] APPM requirements
>
> Speaking of “requirements”…
>
> What’s the thought on using APPM with a non-permanent setup?
>
> Fwiw, I’m using the mach2 now with an st8300m + fs128 at about 1040mm focal length and am “visually” seeing
> decent round stars with 5 minute unguided exposures.
>
> I’ve only had the mount for a couple weeks, but I also used the 130GT at 614mm with (iirc) 20 minute exposures
> unguided.
>
> Yes, objects do not land in the center of the chip on a goto , but it is usually close enough such that I can plate solve
> , sync , then goto again (for proper framing).
>
> I’m guessing APPM might help with longer exposures , and also with objects low on horizon affected by
> atmospheric distortion… the latter would be nice to correct for.  At this point I image objects when they are fairly
> high on the sky.
>
> What would be the guidelines for a “portable” setup ?
> Eg
> a) create model at the site but it could be reused for the same location?
>  b) or.. it is necessary to re-create model if the mount is moved.. ie polar alignment is re-done?
>
> I’ve just wondered about the practicality for a non-permanent setup, and the conditions where APPM is needed for
> unguided imaging… eg the focal length where APPM becomes effective over just the encoders on a polar aligned
> mount..  Or is the benefit simply repeatable pointing accuracy?
>
> Thx
>
>
>
>
>       On Mar 23, 2021, at 12:39 PM, Dean Jacobsen <deanjacobsen@...> wrote:
>
>
>
>       Ray's APCC/APPM on-line manual is a great place to start.
>
>       https://www.siriusimaging.com/Help/APCC/index.html
>
>       There is a specific section for APPM that I used to get everything set up.
>       --
>       Dean Jacobsen
>       http://astrophoto.net/wp/
>       Image Gallery - http://astrophoto.net/wp/image-gallery/
>       Astrobin Image Gallery - https://www.astrobin.com/users/deanjacobsen/
> <https://www.astrobin.com/users/deanjacobsen/>
>       Amateur Radio Call Sign - W6DBJ
>
>






Ray Gralak
 

Theoretically, you could use an existing model if polar-alignment was about the same in each.

Also, you could do a short model run to get the polar alignment terms at the new site, and just update them in APCC, but there is not (yet!) an automatic procedure to do that.

-Ray

-----Original Message-----
From: main@ap-gto.groups.io [mailto:main@ap-gto.groups.io] On Behalf Of ap@CaptivePhotons.com
Sent: Wednesday, March 24, 2021 9:30 AM
To: main@ap-gto.groups.io
Subject: Re: [ap-gto] APPM requirements

I use TSX tPoint now with a MyT, and anticipating the 1100 soon.



Does this mean that APPM does not have a concept similar to the recalibrate of TSX?



I have a (something like) 200 point model, but each time I set up I just run 15-20 points and it recalibrates for the
new polar align (etc) and effectively shifts the prior model slightly to line up in some way.



It’s handy. It can be especially handle if there are a fair number of clouds that may make it difficult to get a full
model run.



It’s not a killer issue since generally there’s plenty of time before full-enough dark to image, but…



So no “recalibrate” type run in APPM?





From: main@ap-gto.groups.io [mailto:main@ap-gto.groups.io] On Behalf Of Jeffc via groups.io
Sent: Wednesday, March 24, 2021 12:26 PM
To: main@ap-gto.groups.io
Subject: Re: [ap-gto] APPM requirements



Thx Ray for the info... this kinda confirms what I was thinking... create a model after polar aligning. (I just need to
figure out a repeatable routine. A project for the full moon weekend.)



-jeff



On Wed, Mar 24, 2021 at 7:39 AM Ray Gralak <iogroups@siriusimaging.com> wrote:

Hi Jeff,

> I’ve just wondered about the practicality for a non-permanent setup, and the conditions where APPM is
needed for
> unguided imaging… eg the focal length where APPM becomes effective over just the encoders on a polar
aligned
> mount.. Or is the benefit simply repeatable pointing accuracy?

A pointing model will improve both tracking and pointing accuracy, including accounting for drift from polar
alignment error.

However, if you move the mount you will need to recreate the model from scratch, but that should not take
much time. Usually, APPM will do between 2-3 points per minute, so you should easily be able to do a 50-point
model (25 points per side) in about 15-25 minutes. You can do this even before the skies are completely dark, thus
not losing any imaging time.

The accuracy of a model is roughly related to the square root of the number of points on each side. For
example, going from 25 to 100 points per side will roughly double the tracking and pointing accuracy (because 100
is four times 25 and the square root of four is two!).

-Ray

> -----Original Message-----
> From: main@ap-gto.groups.io [mailto:main@ap-gto.groups.io] On Behalf Of Jeffc
> Sent: Tuesday, March 23, 2021 1:54 PM
> To: main@ap-gto.groups.io
> Subject: Re: [ap-gto] APPM requirements
>
> Speaking of “requirements”…
>
> What’s the thought on using APPM with a non-permanent setup?
>
> Fwiw, I’m using the mach2 now with an st8300m + fs128 at about 1040mm focal length and am “visually”
seeing
> decent round stars with 5 minute unguided exposures.
>
> I’ve only had the mount for a couple weeks, but I also used the 130GT at 614mm with (iirc) 20 minute
exposures
> unguided.
>
> Yes, objects do not land in the center of the chip on a goto , but it is usually close enough such that I can
plate solve
> , sync , then goto again (for proper framing).
>
> I’m guessing APPM might help with longer exposures , and also with objects low on horizon affected by
> atmospheric distortion… the latter would be nice to correct for. At this point I image objects when they are
fairly
> high on the sky.
>
> What would be the guidelines for a “portable” setup ?
> Eg
> a) create model at the site but it could be reused for the same location?
> b) or.. it is necessary to re-create model if the mount is moved.. ie polar alignment is re-done?
>
> I’ve just wondered about the practicality for a non-permanent setup, and the conditions where APPM is
needed for
> unguided imaging… eg the focal length where APPM becomes effective over just the encoders on a polar
aligned
> mount.. Or is the benefit simply repeatable pointing accuracy?
>
> Thx
>
>
>
>
> On Mar 23, 2021, at 12:39 PM, Dean Jacobsen <deanjacobsen@outlook.com> wrote:
>
>
>
> Ray's APCC/APPM on-line manual is a great place to start.
>
> https://www.siriusimaging.com/Help/APCC/index.html
>
> There is a specific section for APPM that I used to get everything set up.
> --
> Dean Jacobsen
> http://astrophoto.net/wp/
> Image Gallery - http://astrophoto.net/wp/image-gallery/ <http://astrophoto.net/wp/image-gallery/>
> Astrobin Image Gallery - https://www.astrobin.com/users/deanjacobsen/
<https://www.astrobin.com/users/deanjacobsen/>
> <https://www.astrobin.com/users/deanjacobsen/>
> Amateur Radio Call Sign - W6DBJ
>
>








ap@CaptivePhotons.com
 

Thanks.

-----Original Message-----
From: main@ap-gto.groups.io [mailto:main@ap-gto.groups.io] On Behalf Of Ray Gralak via groups.io
Sent: Wednesday, March 24, 2021 12:47 PM
To: main@ap-gto.groups.io
Subject: Re: [ap-gto] APPM requirements

Theoretically, you could use an existing model if polar-alignment was about the same in each.

Also, you could do a short model run to get the polar alignment terms at the new site, and just update them in APCC, but there is not (yet!) an automatic procedure to do that.

-Ray

-----Original Message-----
From: main@ap-gto.groups.io [mailto:main@ap-gto.groups.io] On Behalf
Of ap@CaptivePhotons.com
Sent: Wednesday, March 24, 2021 9:30 AM
To: main@ap-gto.groups.io
Subject: Re: [ap-gto] APPM requirements

I use TSX tPoint now with a MyT, and anticipating the 1100 soon.



Does this mean that APPM does not have a concept similar to the recalibrate of TSX?



I have a (something like) 200 point model, but each time I set up I
just run 15-20 points and it recalibrates for the new polar align (etc) and effectively shifts the prior model slightly to line up in some way.



It’s handy. It can be especially handle if there are a fair number of
clouds that may make it difficult to get a full model run.



It’s not a killer issue since generally there’s plenty of time before
full-enough dark to image, but…



So no “recalibrate” type run in APPM?





From: main@ap-gto.groups.io [mailto:main@ap-gto.groups.io] On Behalf
Of Jeffc via groups.io
Sent: Wednesday, March 24, 2021 12:26 PM
To: main@ap-gto.groups.io
Subject: Re: [ap-gto] APPM requirements



Thx Ray for the info... this kinda confirms what I was thinking...
create a model after polar aligning. (I just need to figure out a
repeatable routine. A project for the full moon weekend.)



-jeff



On Wed, Mar 24, 2021 at 7:39 AM Ray Gralak <iogroups@siriusimaging.com> wrote:

Hi Jeff,

> I’ve just wondered about the practicality for a non-permanent
setup, and the conditions where APPM is needed for
> unguided imaging… eg the focal length where APPM becomes effective
over just the encoders on a polar aligned
> mount.. Or is the benefit simply repeatable pointing accuracy?

A pointing model will improve both tracking and pointing accuracy,
including accounting for drift from polar alignment error.

However, if you move the mount you will need to recreate the model
from scratch, but that should not take much time. Usually, APPM will
do between 2-3 points per minute, so you should easily be able to do a
50-point model (25 points per side) in about 15-25 minutes. You can do this even before the skies are completely dark, thus not losing any imaging time.

The accuracy of a model is roughly related to the square root of the
number of points on each side. For example, going from 25 to 100
points per side will roughly double the tracking and pointing accuracy (because 100 is four times 25 and the square root of four is two!).

-Ray

> -----Original Message-----
> From: main@ap-gto.groups.io [mailto:main@ap-gto.groups.io] On Behalf Of Jeffc
> Sent: Tuesday, March 23, 2021 1:54 PM
> To: main@ap-gto.groups.io
> Subject: Re: [ap-gto] APPM requirements
>
> Speaking of “requirements”…
>
> What’s the thought on using APPM with a non-permanent setup?
>
> Fwiw, I’m using the mach2 now with an st8300m + fs128 at about 1040mm focal length and am “visually”
seeing
> decent round stars with 5 minute unguided exposures.
>
> I’ve only had the mount for a couple weeks, but I also used the
130GT at 614mm with (iirc) 20 minute exposures
> unguided.
>
> Yes, objects do not land in the center of the chip on a goto , but
it is usually close enough such that I can plate solve
> , sync , then goto again (for proper framing).
>
> I’m guessing APPM might help with longer exposures , and also with objects low on horizon affected by
> atmospheric distortion… the latter would be nice to correct for.
At this point I image objects when they are fairly
> high on the sky.
>
> What would be the guidelines for a “portable” setup ?
> Eg
> a) create model at the site but it could be reused for the same location?
> b) or.. it is necessary to re-create model if the mount is moved.. ie polar alignment is re-done?
>
> I’ve just wondered about the practicality for a non-permanent
setup, and the conditions where APPM is needed for
> unguided imaging… eg the focal length where APPM becomes effective
over just the encoders on a polar aligned
> mount.. Or is the benefit simply repeatable pointing accuracy?
>
> Thx
>
>
>
>
> On Mar 23, 2021, at 12:39 PM, Dean Jacobsen <deanjacobsen@outlook.com> wrote:
>
>
>
> Ray's APCC/APPM on-line manual is a great place to start.
>
> https://www.siriusimaging.com/Help/APCC/index.html
>
> There is a specific section for APPM that I used to get everything set up.
> --
> Dean Jacobsen
> http://astrophoto.net/wp/
> Image Gallery - http://astrophoto.net/wp/image-gallery/ <http://astrophoto.net/wp/image-gallery/>
> Astrobin Image Gallery - https://www.astrobin.com/users/deanjacobsen/
<https://www.astrobin.com/users/deanjacobsen/>
> <https://www.astrobin.com/users/deanjacobsen/>
> Amateur Radio Call Sign - W6DBJ
>
>