Dumb question about APPM


Dean Jacobsen
 

I'm reading the APCC/APPM manual and setting up the software for a trip out to the observatory next week where I will try to get pointing and tracking correction enabled on the Mach2 for the first time.

I was wondering about settings in the measurement points tab of APPM...

Because of light pollution domes to the east and the west, I only start imaging when my object is at least 45 degrees high in the eastern sky and I never follow the object below 45 degrees altitude in the western sky.

So, for the purpose of collecting measurement points, is there any need to set the Min. Altitude to anything less than 45 degrees or maybe 40 degrees?

With the Min. Altitude selector set to 40 degrees, the medium map default points are significantly less than with the selector off [57 vs. 155].

The only exception to my usual practice is where I am imaging high in the north where I may start objects 1/2 hour earlier than 45 degrees altitude.
--
Dean Jacobsen
http://astrophoto.net/wp/ 
Image Gallery - http://astrophoto.net/wp/image-gallery/
Astrobin - https://www.astrobin.com/users/deanjacobsen/ 


Ray Gralak
 

Hi Dean,

 

> So, for the purpose of collecting measurement points, is there any need to set the Min. Altitude to anything less than

> 45 degrees or maybe 40 degrees?

 

No, there isn't.

 

> With the Min. Altitude selector set to 40 degrees, the medium map default points are significantly less than with the

> selector off [57 vs. 155].

 

You can increase the density of either RA or Dec points by changing the "Declination Spacing" and "Right Ascension Spacing" sliders. You can create quite dense models very easily by decreasing the spacing of either of these.

> The only exception to my usual practice is where I am imaging high in the north where I may start objects 1/2 hour

> earlier than 45 degrees altitude.

 

If you create Horizon limits in APCC, APPM can use them if you enabled the "Use APPCC Horizon Limits".

 

Below is a screen shot with these items highlighted. Notice in the map that I have elected to use my Horizon limits so APPM requires both the Min Altitude (31 degrees in this case), and the horizon limits to define points.

 

 

-Ray Gralak

Author of APCC (Astro-Physics Command Center): https://www.astro-physics.com/apcc-pro

Author of PEMPro V3:  https://www.ccdware.com

Author of Astro-Physics V2 ASCOM Driver: https://www.siriusimaging.com/apdriver

 

> -----Original Message-----

> From: main@ap-gto.groups.io [mailto:main@ap-gto.groups.io] On Behalf Of Dean Jacobsen

> Sent: Saturday, June 6, 2020 8:13 AM

> To: main@ap-gto.groups.io

> Subject: [ap-gto] Dumb question about APPM

>

> I'm reading the APCC/APPM manual and setting up the software for a trip out to the observatory next week where I

> will try to get pointing and tracking correction enabled on the Mach2 for the first time.

>

> I was wondering about settings in the measurement points tab of APPM...

>

> Because of light pollution domes to the east and the west, I only start imaging when my object is at least 45 degrees

> high in the eastern sky and I never follow the object below 45 degrees altitude in the western sky.

>

> So, for the purpose of collecting measurement points, is there any need to set the Min. Altitude to anything less than

> 45 degrees or maybe 40 degrees?

>

> With the Min. Altitude selector set to 40 degrees, the medium map default points are significantly less than with the

> selector off [57 vs. 155].

>

> The only exception to my usual practice is where I am imaging high in the north where I may start objects 1/2 hour

> earlier than 45 degrees altitude.

> --

> Dean Jacobsen

> http://astrophoto.net/wp/  <http://astrophoto.net/wp/>

> Image Gallery - http://astrophoto.net/wp/image-gallery/

> Astrobin - https://www.astrobin.com/users/deanjacobsen/  <https://www.astrobin.com/users/deanjacobsen/>


Dean Jacobsen
 

Thanks for the pointers Ray.   I will definitely use the horizon limits feature.
--
Dean Jacobsen
http://astrophoto.net/wp/ 
Image Gallery - http://astrophoto.net/wp/image-gallery/
Astrobin - https://www.astrobin.com/users/deanjacobsen/ 


Ray Gralak
 

Dean,

A few more tips:

* If you want to see the order of the plate solves, enable the "Show Order" checkbox. You can animate the point order by clicking the "animate" button. This is just purely a visual display. You don't need to be connected to the mount or a camera.

* If you want to do a daytime test of APPM connected to the mount, on APPM's "Run" tab enable the "Skip Plate Solves (for Testing)" check box.

* If you want to test plate solves in the daytime, select "NASA SkyView (Internet)" for the camera type. APPM will pull an image from the Nasa SkyView website at the mount's current RA/Dec and with the correct image scale, which can be configured on the Plate Solve Settings tab. Of course then make sure to uncheck the option to skip plate solves! :-)

-Ray Gralak
Author of APCC (Astro-Physics Command Center): https://www.astro-physics.com/apcc-pro
Author of PEMPro V3: https://www.ccdware.com
Author of Astro-Physics V2 ASCOM Driver: https://www.siriusimaging.com/apdriver

-----Original Message-----
From: main@ap-gto.groups.io [mailto:main@ap-gto.groups.io] On Behalf Of Dean Jacobsen
Sent: Saturday, June 6, 2020 9:15 AM
To: main@ap-gto.groups.io
Subject: Re: [ap-gto] Dumb question about APPM

Thanks for the pointers Ray. I will definitely use the horizon limits feature.
--
Dean Jacobsen
http://astrophoto.net/wp/ <http://astrophoto.net/wp/>
Image Gallery - http://astrophoto.net/wp/image-gallery/
Astrobin - https://www.astrobin.com/users/deanjacobsen/ <https://www.astrobin.com/users/deanjacobsen/>


Dean Jacobsen
 

Aha!  Very cool.  I will definitely give it a trial run in the garage.  Thanks Ray.
--
Dean Jacobsen
http://astrophoto.net/wp/ 
Image Gallery - http://astrophoto.net/wp/image-gallery/
Astrobin - https://www.astrobin.com/users/deanjacobsen/ 


Dean Jacobsen
 
Edited

On Sat, Jun 6, 2020 at 09:39 AM, Ray Gralak wrote:
If you want to test plate solves in the daytime, select "NASA SkyView (Internet)" for the camera type. APPM will pull an image from the Nasa SkyView website at the mount's current RA/Dec and with the correct image scale, which can be configured on the Plate Solve Settings tab. Of course then make sure to uncheck the option to skip plate solves! :-)
The test run worked fine.  Now to execute under the stars.

Another dumb question...

When using the full sky model derived from the APPM mapping run, when should a meridian flip be executed?  As I am following an object higher in the east  I assume the model is using the mapped points on the east side of the mount to calculate the tracking rate.  Then the object crosses the meridian so I assume that I want to take advantage of the modeling of the mapped points on the west side of the meridian as the object moves into the west and then down. 

So, when should I flip the mount?

Is it OK to go 1/2 hour or one hour master the meridian before executing a flip?
 
--
Dean Jacobsen
http://astrophoto.net/wp/ 
Image Gallery - http://astrophoto.net/wp/image-gallery/
Astrobin - https://www.astrobin.com/users/deanjacobsen/ 


Ray Gralak
 

Hi Dean,

When using the full sky model derived from the APPM mapping run, when should a meridian flip be executed?
APCC and APPM can also map data points with counterweight up! Thus some parts of the sky can have a different model depending on the pier side.

To do this you need to setup Meridian Limits, which provides a way to automatically change the mount's flip point based on declination.

APPM will automatically map counterweight up points once you setup Meridian limits and enable "Use APCC Meridian Limits" in APPM.

BTW, providing mapping to counterweight-up points is unique to Astro-Physics sky modeling (e.g. TPoint and 10 Micron models can't do this).

-Ray Gralak
Author of APCC (Astro-Physics Command Center): https://www.astro-physics.com/apcc-pro
Author of PEMPro V3: https://www.ccdware.com
Author of Astro-Physics V2 ASCOM Driver: https://www.siriusimaging.com/apdriver

-----Original Message-----
From: main@ap-gto.groups.io [mailto:main@ap-gto.groups.io] On Behalf Of Dean Jacobsen
Sent: Saturday, June 6, 2020 2:22 PM
To: main@ap-gto.groups.io
Subject: Re: [ap-gto] Dumb question about APPM

On Sat, Jun 6, 2020 at 09:39 AM, Ray Gralak wrote:


If you want to test plate solves in the daytime, select "NASA SkyView (Internet)" for the camera type. APPM
will pull an image from the Nasa SkyView website at the mount's current RA/Dec and with the correct image scale,
which can be configured on the Plate Solve Settings tab. Of course then make sure to uncheck the option to skip
plate solves! :-)

The test run worked fine. Now to execute under the stars.

Another dumb question...

When using the full sky model derived from the APPM mapping run, when should a meridian flip be executed? As I
am following an object higher in the east I assume the model is using the mapped points on the east side of the
mount to calculate the tracking rate. Then the object crosses the meridian so I assume that I want to take advantage
of the modeling of the mapped points on the west side of the meridian as the object moves into the west and then
down.

So, when should I flip the mount?

--
Dean Jacobsen
http://astrophoto.net/wp/ <http://astrophoto.net/wp/>
Image Gallery - http://astrophoto.net/wp/image-gallery/
Astrobin - https://www.astrobin.com/users/deanjacobsen/ <https://www.astrobin.com/users/deanjacobsen/>


Worsel
 

Ray
I hope I understand this. I may be confusing meridian limits and meridian delay

This suggests that you could generate a model with the meridian delay VERY far east (or west), i.e. a substantial number of the points would be CW up.  Would such a model be valid only under those conditions or could it be used all the time even for areas of the sky where the model was CW up, but the actual image was CW down, because the meridian delay was changed between modelling and imaging? 

For example, assume the model was generated with a meridian east delay of 4 hours.  Many of the east side points will be CW up.  Then later, I picked an object to image that is 2 hours east of the meridian BUT I set the meridian delay at 1 hour, so the mount is CW down.  Will the tracking be 'less' good?

Bryan


Ray Gralak
 

Bryan,

I can't tell you how well your setup can be modeled. Some large mirrored scopes don't model well but refractors usually model very well.

APPM and APCC can distinguish which pier side model to use. CW up and CW down imaging are not usually equivalent.

You could experiment to see if a CW down-only model will work for CW up imaging. If not you will have to have APCC map CW up points.

-Ray Gralak
Author of APCC (Astro-Physics Command Center): https://www.astro-physics.com/apcc-pro
Author of PEMPro V3: https://www.ccdware.com
Author of Astro-Physics V2 ASCOM Driver: https://www.siriusimaging.com/apdriver

-----Original Message-----
From: main@ap-gto.groups.io [mailto:main@ap-gto.groups.io] On Behalf Of Worsel via groups.io
Sent: Saturday, June 6, 2020 8:57 PM
To: main@ap-gto.groups.io
Subject: Re: [ap-gto] Dumb question about APPM

Ray
I hope I understand this. I may be confusing meridian limits and meridian delay

This suggests that you could generate a model with the meridian delay VERY far east (or west), i.e. a substantial
number of the points would be CW up. Would such a model be valid only under those conditions or could it be used
all the time even for areas of the sky where the model was CW up, but the actual image was CW down, because the
meridian delay was changed between modelling and imaging?

For example, assume the model was generated with a meridian east delay of 4 hours. Many of the east side points
will be CW up. Then later, I picked an object to image that is 2 hours east of the meridian BUT I set the meridian
delay at 1 hour, so the mount is CW down. Will the tracking be 'less' good?

Bryan


Dean Jacobsen
 

On Sat, Jun 6, 2020 at 07:42 PM, Ray Gralak wrote:
APCC and APPM can also map data points with counterweight up! Thus some parts of the sky can have a different model depending on the pier side.

To do this you need to setup Meridian Limits, which provides a way to automatically change the mount's flip point based on declination.

APPM will automatically map counterweight up points once you setup Meridian limits and enable "Use APCC Meridian Limits" in APPM.

BTW, providing mapping to counterweight-up points is unique to Astro-Physics sky modeling (e.g. TPoint and 10 Micron models can't do this).
Excellent.  That is a nice feature.  No matter which optical tube I am using, I can always image an hour past the meridian without striking the pier with the tube or the saddle plate. 

.. .re-reading the Meridian Tab stuff in the manual...
 
--
Dean Jacobsen
http://astrophoto.net/wp/ 
Image Gallery - http://astrophoto.net/wp/image-gallery/
Astrobin - https://www.astrobin.com/users/deanjacobsen/ 


 

Hi Ray

>>>Some large mirrored scopes don't model well but refractors usually model very well

is that primarily from mirror flop, or other issues? we have a planewave CDK17, hoping it models well :)

On Sat, Jun 6, 2020 at 9:20 PM Ray Gralak <groups3@...> wrote:
Bryan,

I can't tell you how well your setup can be modeled. Some large mirrored scopes don't model well but refractors usually model very well.

APPM and APCC can distinguish which pier side model to use. CW up and CW down imaging are not usually equivalent.

You could experiment to see if a CW down-only model will work for CW up imaging. If not you will have to have APCC map CW up points.

-Ray Gralak
Author of APCC (Astro-Physics Command Center): https://www.astro-physics.com/apcc-pro
Author of PEMPro V3:  https://www.ccdware.com
Author of Astro-Physics V2 ASCOM Driver: https://www.siriusimaging.com/apdriver


> -----Original Message-----
> From: main@ap-gto.groups.io [mailto:main@ap-gto.groups.io] On Behalf Of Worsel via groups.io
> Sent: Saturday, June 6, 2020 8:57 PM
> To: main@ap-gto.groups.io
> Subject: Re: [ap-gto] Dumb question about APPM
>
> Ray
> I hope I understand this. I may be confusing meridian limits and meridian delay
>
> This suggests that you could generate a model with the meridian delay VERY far east (or west), i.e. a substantial
> number of the points would be CW up.  Would such a model be valid only under those conditions or could it be used
> all the time even for areas of the sky where the model was CW up, but the actual image was CW down, because the
> meridian delay was changed between modelling and imaging?
>
> For example, assume the model was generated with a meridian east delay of 4 hours.  Many of the east side points
> will be CW up.  Then later, I picked an object to image that is 2 hours east of the meridian BUT I set the meridian
> delay at 1 hour, so the mount is CW down.  Will the tracking be 'less' good?
>
> Bryan
>






--
Brian 



Brian Valente


Ray Gralak
 
Edited

Hi Brian,

Yes, mirror flop is one thing. It depends on how well the telescope "bends" as if it were a solid tube with a specific Young's modulus.

That said, I have been working on improvements to account for residuals not covered by the usual pointing terms.

-Ray Gralak
Author of APCC (Astro-Physics Command Center): https://www.astro-physics.com/apcc-pro
Author of PEMPro V3: https://www.ccdware.com
Author of Astro-Physics V2 ASCOM Driver: https://www.siriusimaging.com/apdriver

-----Original Message-----
From: main@ap-gto.groups.io [mailto:main@ap-gto.groups.io] On Behalf Of Brian Valente
Sent: Saturday, June 6, 2020 9:25 PM
To: main@ap-gto.groups.io
Subject: Re: [ap-gto] Dumb question about APPM

Hi Ray

Some large mirrored scopes don't model well but refractors usually model very well
is that primarily from mirror flop, or other issues? we have a planewave CDK17, hoping it models well :)

On Sat, Jun 6, 2020 at 9:20 PM Ray Gralak <groups3@...> wrote:


Bryan,

I can't tell you how well your setup can be modeled. Some large mirrored scopes don't model well but
refractors usually model very well.

APPM and APCC can distinguish which pier side model to use. CW up and CW down imaging are not usually
equivalent.

You could experiment to see if a CW down-only model will work for CW up imaging. If not you will have to
have APCC map CW up points.

-Ray Gralak
Author of APCC (Astro-Physics Command Center): https://www.astro-physics.com/apcc-pro
Author of PEMPro V3: https://www.ccdware.com
Author of Astro-Physics V2 ASCOM Driver: https://www.siriusimaging.com/apdriver


> -----Original Message-----
> From: main@ap-gto.groups.io [mailto:main@ap-gto.groups.io] On Behalf Of Worsel via groups.io
> Sent: Saturday, June 6, 2020 8:57 PM
> To: main@ap-gto.groups.io
> Subject: Re: [ap-gto] Dumb question about APPM
>
> Ray
> I hope I understand this. I may be confusing meridian limits and meridian delay
>
> This suggests that you could generate a model with the meridian delay VERY far east (or west), i.e. a
substantial
> number of the points would be CW up. Would such a model be valid only under those conditions or could it
be used
> all the time even for areas of the sky where the model was CW up, but the actual image was CW down,
because the
> meridian delay was changed between modelling and imaging?
>
> For example, assume the model was generated with a meridian east delay of 4 hours. Many of the east side
points
> will be CW up. Then later, I picked an object to image that is 2 hours east of the meridian BUT I set the
meridian
> delay at 1 hour, so the mount is CW down. Will the tracking be 'less' good?
>
> Bryan
>








--

Brian



Brian Valente
portfolio brianvalentephotography.com <http://brianvalentephotography.com>


Dean Jacobsen
 

On Sat, Jun 6, 2020 at 07:42 PM, Ray Gralak wrote:
APCC and APPM can also map data points with counterweight up! Thus some parts of the sky can have a different model depending on the pier side.

To do this you need to setup Meridian Limits, which provides a way to automatically change the mount's flip point based on declination.

APPM will automatically map counterweight up points once you setup Meridian limits and enable "Use APCC Meridian Limits" in APPM.
OK, more in the "dumb questions about APCC & APPM" series:

I have been exploring the Meridian Limits feature and have been studying the manual.

My usual practice has been to image about 1 hour past the meridian and then flip the mount and follow the object down in the western sky for another 1.5 or two hours.

I have set up a one hour post meridian limit for all declinations.  The APPM map now shows counterweight up points west of the meridian for a mapping run.

Now I am wondering if all of this [setting up meridian limits and counterweight up point mapping] is necessary.

Flipping the mount and re-acquiring the target takes the same amount of time at the meridian as it does one hour past the meridian.

Is there any real benefit to following the object an hour past the meridian with a proper model that incorporates couterweight up point mapping vs. just flipping at the meridian and not using meridian limits and counterweight up points in the map?

I have always followed objects across the meridian because I didn't want to take the time to manually flip the mount, re-center,, and get guiding going while pointing at the best part of the sky.
--
Dean Jacobsen
http://astrophoto.net/wp/ 
Image Gallery - http://astrophoto.net/wp/image-gallery/
Astrobin - https://www.astrobin.com/users/deanjacobsen/ 


Ray Gralak
 

Is there any real benefit to following the object an hour past the meridian with a proper model that incorporates
couterweight up point mapping vs. just flipping at the meridian and not using meridian limits and counterweight up
points in the map?
Did someone tell you there wasn't?

First it saves time not having to flip the mount.

Second, the images will be flipped unless you have a rotator to compensate, so you'll have an extra step in processing.

I have set up a one hour post meridian limit for all declinations. The APPM map now shows counterweight up points
west of the meridian for a mapping run.
Are you sure that is safe for all declinations? For some setups that might allow a collision at certain declinations.

-Ray Gralak
Author of APCC (Astro-Physics Command Center): https://www.astro-physics.com/apcc-pro
Author of PEMPro V3: https://www.ccdware.com
Author of Astro-Physics V2 ASCOM Driver: https://www.siriusimaging.com/apdriver


-----Original Message-----
From: main@ap-gto.groups.io [mailto:main@ap-gto.groups.io] On Behalf Of Dean Jacobsen
Sent: Monday, June 8, 2020 7:49 AM
To: main@ap-gto.groups.io
Subject: Re: [ap-gto] Dumb question about APPM

On Sat, Jun 6, 2020 at 07:42 PM, Ray Gralak wrote:


APCC and APPM can also map data points with counterweight up! Thus some parts of the sky can have a
different model depending on the pier side.

To do this you need to setup Meridian Limits, which provides a way to automatically change the mount's flip
point based on declination.

APPM will automatically map counterweight up points once you setup Meridian limits and enable "Use APCC
Meridian Limits" in APPM.

OK, more in the "dumb questions about APCC & APPM" series:

I have been exploring the Meridian Limits feature and have been studying the manual.

My usual practice has been to image about 1 hour past the meridian and then flip the mount and follow the object
down in the western sky for another 1.5 or two hours.

I have set up a one hour post meridian limit for all declinations. The APPM map now shows counterweight up points
west of the meridian for a mapping run.

Now I am wondering if all of this [setting up meridian limits and counterweight up point mapping] is necessary.

Flipping the mount and re-acquiring the target takes the same amount of time at the meridian as it does one hour
past the meridian.

Is there any real benefit to following the object an hour past the meridian with a proper model that incorporates
couterweight up point mapping vs. just flipping at the meridian and not using meridian limits and counterweight up
points in the map?

I have always followed objects across the meridian because I didn't want to take the time to manually flip the mount,
re-center,, and get guiding going while pointing at the best part of the sky.
--
Dean Jacobsen
http://astrophoto.net/wp/ <http://astrophoto.net/wp/>
Image Gallery - http://astrophoto.net/wp/image-gallery/
Astrobin - https://www.astrobin.com/users/deanjacobsen/ <https://www.astrobin.com/users/deanjacobsen/>


Dean Jacobsen
 

On Mon, Jun 8, 2020 at 08:03 AM, Ray Gralak wrote:
Did someone tell you there wasn't?
No, I guess this is why I included the question in my dumb question series.  ;-)

Yes, I am safe at all declinations.

Aligning flipped images is not an issue.

It is very rare that I image an object which I can follow into the west with the OTA under the tube.  That might happen once a year and I can set up that special case in the software when it is appropriate.  So I just assume that I am always going to be flipping the mount an hour past the meridian, and that is safe for all of my OTAs.
 
I was just wondering if there was some other reason that I may not be aware of that would tend to prefer one method vs. the other.
--
Dean Jacobsen
http://astrophoto.net/wp/ 
Image Gallery - http://astrophoto.net/wp/image-gallery/
Astrobin - https://www.astrobin.com/users/deanjacobsen/