APPM error


Matthew Hughes
 

Hi Ray/ Anyone,


I am getting an error when I try to plate solve on the RUN tab in APPM. never used it before cant seem to get it working.


"Invalid scale hint"


I am using SGP pro PlateSolve2.


TAK 106 EDX at arc scale 0.9. Pretty sure all settings entered correctly. Plate solve works fine with just SGP alone.

Not sure if this is the correct forum..

I've uploaded files at folder called Matthew Hughes, APPM files. Log zipper.


Any help thanks.

Matt


Ray Gralak
 

Matt,

Make sure you are running the latest released version of SGP.

-Ray Gralak
Author of APCC (Astro-Physics Command Center): http://www.astro-physics.com/index.htm?products/accessories/software/apcc/apcc
Author of PEMPro: http://www.ccdware.com
Author of Astro-Physics V2 ASCOM Driver: http://www.gralak.com/apdriver
Author of PulseGuide: http://www.pulseguide.com
Author of Sigma: http://www.gralak.com/sigma

-----Original Message-----
From: ap-gto@yahoogroups.com [mailto:ap-gto@yahoogroups.com]
Sent: Friday, November 3, 2017 10:10 PM
To: ap-gto@yahoogroups.com
Subject: [ap-gto] APPM error



Hi Ray/ Anyone,




I am getting an error when I try to plate solve on the RUN tab in APPM. never used it before cant seem to get
it working.




"Invalid scale hint"




I am using SGP pro PlateSolve2.




TAK 106 EDX at arc scale 0.9. Pretty sure all settings entered correctly. Plate solve works fine with just SGP
alone.

Not sure if this is the correct forum..

I've uploaded files at folder called Matthew Hughes, APPM files. Log zipper.




Any help thanks.

Matt


Matthew Hughes
 

Ah yeah..... that worked. Building first model now... updates updates updates...

Thanks Ray..

Regards,

Matt Hughes

On 5 Nov 2017, at 00:02, 'Ray Gralak (Groups)' groups3@... [ap-gto] <ap-gto@...> wrote:

 

Matt,

Make sure you are running the latest released version of SGP.

-Ray Gralak
Author of APCC (Astro-Physics Command Center): http://www.astro-physics.com/index.htm?products/accessories/software/apcc/apcc
Author of PEMPro: http://www.ccdware.com
Author of Astro-Physics V2 ASCOM Driver: http://www.gralak.com/apdriver
Author of PulseGuide: http://www.pulseguide.com
Author of Sigma: http://www.gralak.com/sigma

> -----Original Message-----
> From: ap-gto@... [mailto:ap-gto@...]
> Sent: Friday, November 3, 2017 10:10 PM
> To: ap-gto@...
> Subject: [ap-gto] APPM error
>
>
>
> Hi Ray/ Anyone,
>
>
>
>
> I am getting an error when I try to plate solve on the RUN tab in APPM. never used it before cant seem to get
> it working.
>
>
>
>
> "Invalid scale hint"
>
>
>
>
> I am using SGP pro PlateSolve2.
>
>
>
>
> TAK 106 EDX at arc scale 0.9. Pretty sure all settings entered correctly. Plate solve works fine with just SGP
> alone.
>
> Not sure if this is the correct forum..
>
> I've uploaded files at folder called Matthew Hughes, APPM files. Log zipper.
>
>
>
>
> Any help thanks.
>
> Matt
>
>


Matthew Hughes
 

Hi Ray,

Ok everything seemed to work fine.
I’m thinking that models only work for rigs that are permanent or when imaging from same locations over several nights. A 300 point model looks like taking nearly 3 hours, binning at 2x, 1 sec settling 3 sec imaging using a LUM filter.

Is there any value for a portable rig, doing say 50 points? Then guiding ... will it improve guiding?

Regards,

Matt Hughes

On 5 Nov 2017, at 00:02, 'Ray Gralak (Groups)' groups3@... [ap-gto] <ap-gto@...> wrote:

 

Matt,

Make sure you are running the latest released version of SGP.

-Ray Gralak
Author of APCC (Astro-Physics Command Center): http://www.astro-physics.com/index.htm?products/accessories/software/apcc/apcc
Author of PEMPro: http://www.ccdware.com
Author of Astro-Physics V2 ASCOM Driver: http://www.gralak.com/apdriver
Author of PulseGuide: http://www.pulseguide.com
Author of Sigma: http://www.gralak.com/sigma

> -----Original Message-----
> From: ap-gto@... [mailto:ap-gto@...]
> Sent: Friday, November 3, 2017 10:10 PM
> To: ap-gto@...
> Subject: [ap-gto] APPM error
>
>
>
> Hi Ray/ Anyone,
>
>
>
>
> I am getting an error when I try to plate solve on the RUN tab in APPM. never used it before cant seem to get
> it working.
>
>
>
>
> "Invalid scale hint"
>
>
>
>
> I am using SGP pro PlateSolve2.
>
>
>
>
> TAK 106 EDX at arc scale 0.9. Pretty sure all settings entered correctly. Plate solve works fine with just SGP
> alone.
>
> Not sure if this is the correct forum..
>
> I've uploaded files at folder called Matthew Hughes, APPM files. Log zipper.
>
>
>
>
> Any help thanks.
>
> Matt
>
>


Ray Gralak
 

Hi Matt,

Each setup is different, so how well it will work depends on how good the data can be fit into the modelled terms and the repeatability of pointing.

So, as long as there is nothing causing random pointing errors, then 50 points should significantly improve tracking and pointing accuracy.

Best regards,

-Ray Gralak
Author of APCC (Astro-Physics Command Center): http://www.astro-physics.com/index.htm?products/accessories/software/apcc/apcc
Author of PEMPro: http://www.ccdware.com
Author of Astro-Physics V2 ASCOM Driver: http://www.gralak.com/apdriver
Author of PulseGuide: http://www.pulseguide.com
Author of Sigma: http://www.gralak.com/sigma

-----Original Message-----
From: ap-gto@yahoogroups.com [mailto:ap-gto@yahoogroups.com]
Sent: Saturday, November 4, 2017 9:10 AM
To: ap-gto@yahoogroups.com
Subject: Re: [ap-gto] APPM error



Hi Ray,

Ok everything seemed to work fine.
I’m thinking that models only work for rigs that are permanent or when imaging from same locations over
several nights. A 300 point model looks like taking nearly 3 hours, binning at 2x, 1 sec settling 3 sec imaging
using a LUM filter.

Is there any value for a portable rig, doing say 50 points? Then guiding ... will it improve guiding?


Regards,

Matt Hughes

On 5 Nov 2017, at 00:02, 'Ray Gralak (Groups)' groups3@gralak.com <mailto:groups3@gralak.com> [ap-gto]
<ap-gto@yahoogroups.com> wrote:





Matt,

Make sure you are running the latest released version of SGP.

-Ray Gralak
Author of APCC (Astro-Physics Command Center): http://www.astro-
physics.com/index.htm?products/accessories/software/apcc/apcc <http://www.astro-
physics.com/index.htm?products/accessories/software/apcc/apcc>
Author of PEMPro: http://www.ccdware.com
Author of Astro-Physics V2 ASCOM Driver: http://www.gralak.com/apdriver
<http://www.gralak.com/apdriver>
Author of PulseGuide: http://www.pulseguide.com
Author of Sigma: http://www.gralak.com/sigma

> -----Original Message-----
> From: ap-gto@yahoogroups.com [mailto:ap-gto@yahoogroups.com]
> Sent: Friday, November 3, 2017 10:10 PM
> To: ap-gto@yahoogroups.com
> Subject: [ap-gto] APPM error
>
>
>
> Hi Ray/ Anyone,
>
>
>
>
> I am getting an error when I try to plate solve on the RUN tab in APPM. never used it before cant
seem to get
> it working.
>
>
>
>
> "Invalid scale hint"
>
>
>
>
> I am using SGP pro PlateSolve2.
>
>
>
>
> TAK 106 EDX at arc scale 0.9. Pretty sure all settings entered correctly. Plate solve works fine with
just SGP
> alone.
>
> Not sure if this is the correct forum..
>
> I've uploaded files at folder called Matthew Hughes, APPM files. Log zipper.
>
>
>
>
> Any help thanks.
>
> Matt
>
>




Matthew Hughes
 

Thanks Ray.

Regards,

Matt Hughes

On 5 Nov 2017, at 03:17, 'Ray Gralak (Groups)' groups3@... [ap-gto] <ap-gto@...> wrote:

 

Hi Matt,

Each setup is different, so how well it will work depends on how good the data can be fit into the modelled terms and the repeatability of pointing.

So, as long as there is nothing causing random pointing errors, then 50 points should significantly improve tracking and pointing accuracy.

Best regards,

-Ray Gralak
Author of APCC (Astro-Physics Command Center): http://www.astro-physics.com/index.htm?products/accessories/software/apcc/apcc
Author of PEMPro: http://www.ccdware.com
Author of Astro-Physics V2 ASCOM Driver: http://www.gralak.com/apdriver
Author of PulseGuide: http://www.pulseguide.com
Author of Sigma: http://www.gralak.com/sigma

> -----Original Message-----
> From: ap-gto@... [mailto:ap-gto@...]
> Sent: Saturday, November 4, 2017 9:10 AM
> To: ap-gto@...
> Subject: Re: [ap-gto] APPM error
>
>
>
> Hi Ray,
>
> Ok everything seemed to work fine.
> I’m thinking that models only work for rigs that are permanent or when imaging from same locations over
> several nights. A 300 point model looks like taking nearly 3 hours, binning at 2x, 1 sec settling 3 sec imaging
> using a LUM filter.
>
> Is there any value for a portable rig, doing say 50 points? Then guiding ... will it improve guiding?
>
>
> Regards,
>
> Matt Hughes
>
> On 5 Nov 2017, at 00:02, 'Ray Gralak (Groups)' groups3@... <mailto:groups3@...> [ap-gto]
> <ap-gto@...> wrote:
>
>
>
>
>
> Matt,
>
> Make sure you are running the latest released version of SGP.
>
> -Ray Gralak
> Author of APCC (Astro-Physics Command Center): http://www.astro-
> physics.com/index.htm?products/accessories/software/apcc/apcc <http://www.astro-
> physics.com/index.htm?products/accessories/software/apcc/apcc>
> Author of PEMPro: http://www.ccdware.com
> Author of Astro-Physics V2 ASCOM Driver: http://www.gralak.com/apdriver
> <http://www.gralak.com/apdriver>
> Author of PulseGuide: http://www.pulseguide.com
> Author of Sigma: http://www.gralak.com/sigma
>
> > -----Original Message-----
> > From: ap-gto@... [mailto:ap-gto@...]
> > Sent: Friday, November 3, 2017 10:10 PM
> > To: ap-gto@...
> > Subject: [ap-gto] APPM error
> >
> >
> >
> > Hi Ray/ Anyone,
> >
> >
> >
> >
> > I am getting an error when I try to plate solve on the RUN tab in APPM. never used it before cant
> seem to get
> > it working.
> >
> >
> >
> >
> > "Invalid scale hint"
> >
> >
> >
> >
> > I am using SGP pro PlateSolve2.
> >
> >
> >
> >
> > TAK 106 EDX at arc scale 0.9. Pretty sure all settings entered correctly. Plate solve works fine with
> just SGP
> > alone.
> >
> > Not sure if this is the correct forum..
> >
> > I've uploaded files at folder called Matthew Hughes, APPM files. Log zipper.
> >
> >
> >
> >
> > Any help thanks.
> >
> > Matt
> >
> >
>
>
>
>


Roland Christen
 

Hi Matt,

Howard and I have done a number of different tests on modeling using a 17"F8 astrograph and here is what I have found. A small model of 36 points on a side will go a long way to giving you great pointing, not perfect by any means, but great enough for all but the most precise needs. And it helps guided imaging for sure because you can use longer guide exposures and much lower aggressiveness which helps in less stable seeing.

It will probably not provide you with perfect unguided imaging, and I think I know why. When you do a plate solve, there is always a small residual error on the order of a few arc seconds. If you do a limited model with just a few points, the plate solve errors dominate. A few arc second error is inconsequential for pointing, but is definitely injurious to unguided imaging. A much larger number of points is needed, which will average out individual plate solve errors. For guided imaging it doesn't matter at all which way you go - limited model or more extensive with large number of points.

Rolando



-----Original Message-----
From: Matthew Hughes matthughes77@... [ap-gto]
To: ap-gto
Sent: Sat, Nov 4, 2017 11:10 am
Subject: Re: [ap-gto] APPM error



Hi Ray,

Ok everything seemed to work fine.
I’m thinking that models only work for rigs that are permanent or when imaging from same locations over several nights. A 300 point model looks like taking nearly 3 hours, binning at 2x, 1 sec settling 3 sec imaging using a LUM filter.

Is there any value for a portable rig, doing say 50 points? Then guiding ... will it improve guiding?

Regards,

Matt Hughes

On 5 Nov 2017, at 00:02, 'Ray Gralak (Groups)' groups3@... [ap-gto] <ap-gto@...> wrote:

 
Matt,

Make sure you are running the latest released version of SGP.

-Ray Gralak
Author of APCC (Astro-Physics Command Center): http://www.astro-physics.com/index.htm?products/accessories/software/apcc/apcc
Author of PEMPro: http://www.ccdware.com
Author of Astro-Physics V2 ASCOM Driver: http://www.gralak.com/apdriver
Author of PulseGuide: http://www.pulseguide.com
Author of Sigma: http://www.gralak.com/sigma

> -----Original Message-----
> From: ap-gto@... [mailto:ap-gto@...]
> Sent: Friday, November 3, 2017 10:10 PM
> To: ap-gto@...
> Subject: [ap-gto] APPM error
>
>
>
> Hi Ray/ Anyone,
>
>
>
>
> I am getting an error when I try to plate solve on the RUN tab in APPM. never used it before cant seem to get
> it working.
>
>
>
>
> "Invalid scale hint"
>
>
>
>
> I am using SGP pro PlateSolve2.
>
>
>
>
> TAK 106 EDX at arc scale 0.9. Pretty sure all settings entered correctly. Plate solve works fine with just SGP
> alone.
>
> Not sure if this is the correct forum..
>
> I've uploaded files at folder called Matthew Hughes, APPM files. Log zipper.
>
>
>
>
> Any help thanks.
>
> Matt
>
>




Matthew Hughes
 

Hi Rolando,

Thankyou for your reply. That makes sense.

I’m just setting up a guiding test (while this enormous moon is out tonight and for the next few nights, 3:30am here downunder) I’m just spending the time experimenting with some of the advanced features. If the clouds stay away I’ll continue to experiment and compare.

I appreciate the advice.

Regards,

Matt Hughes

On 5 Nov 2017, at 03:27, chris1011@... [ap-gto] <ap-gto@...> wrote:

 

Hi Matt,

Howard and I have done a number of different tests on modeling using a 17"F8 astrograph and here is what I have found. A small model of 36 points on a side will go a long way to giving you great pointing, not perfect by any means, but great enough for all but the most precise needs. And it helps guided imaging for sure because you can use longer guide exposures and much lower aggressiveness which helps in less stable seeing.

It will probably not provide you with perfect unguided imaging, and I think I know why. When you do a plate solve, there is always a small residual error on the order of a few arc seconds. If you do a limited model with just a few points, the plate solve errors dominate. A few arc second error is inconsequential for pointing, but is definitely injurious to unguided imaging. A much larger number of points is needed, which will average out individual plate solve errors. For guided imaging it doesn't matter at all which way you go - limited model or more extensive with large number of points.

Rolando




-----Original Message-----
From: Matthew Hughes matthughes77@... [ap-gto] <ap-gto@...>
To: ap-gto <ap-gto@...>
Sent: Sat, Nov 4, 2017 11:10 am
Subject: Re: [ap-gto] APPM error



Hi Ray,

Ok everything seemed to work fine.
I’m thinking that models only work for rigs that are permanent or when imaging from same locations over several nights. A 300 point model looks like taking nearly 3 hours, binning at 2x, 1 sec settling 3 sec imaging using a LUM filter.

Is there any value for a portable rig, doing say 50 points? Then guiding ... will it improve guiding?

Regards,

Matt Hughes

On 5 Nov 2017, at 00:02, 'Ray Gralak (Groups)' groups3@... [ap-gto] <ap-gto@...> wrote:

 
Matt,

Make sure you are running the latest released version of SGP.

-Ray Gralak
Author of APCC (Astro-Physics Command Center): http://www.astro-physics.com/index.htm?products/accessories/software/apcc/apcc
Author of PEMPro: http://www.ccdware.com
Author of Astro-Physics V2 ASCOM Driver: http://www.gralak.com/apdriver
Author of PulseGuide: http://www.pulseguide.com
Author of Sigma: http://www.gralak.com/sigma

> -----Original Message-----
> From: ap-gto@... [mailto:ap-gto@...]
> Sent: Friday, November 3, 2017 10:10 PM
> To: ap-gto@...
> Subject: [ap-gto] APPM error
>
>
>
> Hi Ray/ Anyone,
>
>
>
>
> I am getting an error when I try to plate solve on the RUN tab in APPM. never used it before cant seem to get
> it working.
>
>
>
>
> "Invalid scale hint"
>
>
>
>
> I am using SGP pro PlateSolve2.
>
>
>
>
> TAK 106 EDX at arc scale 0.9. Pretty sure all settings entered correctly. Plate solve works fine with just SGP
> alone.
>
> Not sure if this is the correct forum..
>
> I've uploaded files at folder called Matthew Hughes, APPM files. Log zipper.
>
>
>
>
> Any help thanks.
>
> Matt
>
>




CurtisC
 

"A much larger number of points is needed"

How many do you suggest?


Roland Christen
 

Depends on your setup and what your goal is.

Rolando



-----Original Message-----
From: calypte@... [ap-gto]
To: ap-gto
Sent: Sat, Nov 4, 2017 11:46 am
Subject: Re: [ap-gto] APPM error



"A much larger number of points is needed"

How many do you suggest?



CurtisC
 

"Depends on your setup and what your goal is."

It's a TEC-140 on a Mach1 in an observatory.  The last time I ran APPM, during a bright Moon period this past July, I think it defaulted to something like 180 points.  It failed to solve a few points near the Moon, which I rather expected.  After the APPM run, I did some go-tos to some globular clusters, without doing my usual plate-solves.  The globs were dead-centered.  But they were all in the same general area of the sky.  Some go-tos to other objects in the west weren't quite as accurate, the targets being noticeably off-center.  I don't know what to expect.  Is this good?  Is it sub-par?  If more points would yield more accuracy, I'll do it.  If it's, um, pointless, then I won't bother.  I've never noticed any improvement in tracking.  


Roland Christen
 


 I've never noticed any improvement in tracking.  
Do you mean tracking or guiding? Are you doing unguided tracking and don't see an improvement? Did you turn on the custom tracking?

As for the APPM, that is a question for Ray.

Rolando


-----Original Message-----
From: calypte@... [ap-gto]
To: ap-gto <ap-gto@...>
Sent: Sat, Nov 4, 2017 2:49 pm
Subject: Re: [ap-gto] APPM error



"Depends on your setup and what your goal is."

It's a TEC-140 on a Mach1 in an observatory.  The last time I ran APPM, during a bright Moon period this past July, I think it defaulted to something like 180 points.  It failed to solve a few points near the Moon, which I rather expected.  After the APPM run, I did some go-tos to some globular clusters, without doing my usual plate-solves.  The globs were dead-centered.  But they were all in the same general area of the sky.  Some go-tos to other objects in the west weren't quite as accurate, the targets being noticeably off-center.  I don't know what to expect.  Is this good?  Is it sub-par?  If more points would yield more accuracy, I'll do it.  If it's, um, pointless, then I won't bother.  I've never noticed any improvement in tracking.  




Ray Gralak
 

The globs were dead-centered. But they were all in the same general area of the sky. Some
go-tos to other objects in the west weren't quite as accurate, the targets being noticeably off-center. I don't
know what to expect. Is this good? Is it sub-par? If more points would yield more accuracy, I'll do it. If it's,
um, pointless, then I won't bother.
There's no single answer for your questions. As I have said before, each setup is different so the accuracy of slews and tracking rate corrections depends on how well the data points can be modeled and the amount of pointing randomness. Even a random tugging cable can throw a target off by many arc-seconds or even arc-minutes.

BTW, there is a "Verify" option in APPM to test the accuracy of the model. You can use that to check the model and try to isolate and fix any mechanical issues in parts of the sky where pointing quality is not so good.

-Ray Gralak
Author of APCC (Astro-Physics Command Center): http://www.astro-physics.com/index.htm?products/accessories/software/apcc/apcc
Author of PEMPro: http://www.ccdware.com
Author of Astro-Physics V2 ASCOM Driver: http://www.gralak.com/apdriver
Author of PulseGuide: http://www.pulseguide.com
Author of Sigma: http://www.gralak.com/sigma


-----Original Message-----
From: ap-gto@yahoogroups.com [mailto:ap-gto@yahoogroups.com]
Sent: Saturday, November 4, 2017 12:49 PM
To: ap-gto@yahoogroups.com
Subject: Re: [ap-gto] APPM error



"Depends on your setup and what your goal is."

It's a TEC-140 on a Mach1 in an observatory. The last time I ran APPM, during a bright Moon period this past
July, I think it defaulted to something like 180 points. It failed to solve a few points near the Moon, which I
rather expected. After the APPM run, I did some go-tos to some globular clusters, without doing my usual
plate-solves. The globs were dead-centered. But they were all in the same general area of the sky. Some
go-tos to other objects in the west weren't quite as accurate, the targets being noticeably off-center. I don't
know what to expect. Is this good? Is it sub-par? If more points would yield more accuracy, I'll do it. If it's,
um, pointless, then I won't bother. I've never noticed any improvement in tracking.




CurtisC
 

"Do you mean tracking or guiding? Are you doing unguided tracking and don't see an improvement? Did you turn on the custom tracking?"

Yes, guiding.  I was careless in my terminology.  As to the other question: ??


Roland Christen
 

Guiding is guiding, and your results will be dependent on what software you use and how you set it up. I get excellent results with MaximDL, others prefer PHD. Guiding closes the loop on a star and thus is dependent strictly on guiding parameters and how you set them up. Variables such as polar misalignment, guide parameters, calibration accuracy, guide speed, aggressiveness, Min/Max move settings etc all impact your results. Modeling not so much.

I have found the greatest impact is going to be how well you have polar aligned and kept the mount from drifting, especially in Dec. I aim for at most 1 arc sec per 5 minutes drift in Dec at high altitudes.  I have discussed polar alignment in detail in other posts.

Rolando



-----Original Message-----
From: calypte@... [ap-gto]
To: ap-gto
Sent: Sat, Nov 4, 2017 3:49 pm
Subject: Re: [ap-gto] APPM error



"Do you mean tracking or guiding? Are you doing unguided tracking and don't see an improvement? Did you turn on the custom tracking?"

Yes, guiding.  I was careless in my terminology.  As to the other question: ??



CurtisC
 

The second question, about "custom tracking": yes, it's turned on in APCC.  I had to go out to the observatory to see what you were talking about.  I'm using MaxIm DL 6.xx for guiding.  The matter I was addressing was that I don't see that APPM's sky model has improved my guiding.  Maybe it has, but it's not very visible in the numbers I see as the corrections roll by.  But I think this exchange has established that there's probably not much more I should expect from APPM's sky model.

The reason I've pursued this discussion more than once, as this topic recycles every few months in this forum, is due to what I see at Palomar Observatory, where I work as a volunteer.  There's a sky model in the software for the 200-inch Hale Telescope.  I think the model software was developed by a Caltech programmer.  I don't think it's one of the commercial products (e.g. T-Point or Pinpoint).  I don't know what they did to establish the points of the model.  I've met the man who wrote it (I think), but I've never had a chance to discuss this software with him.  The pointing accuracy of the 200-inch is far beyond anything I see with my own gear.  Cassegrain is the most commonly used focus, f/16 or about 80m FL.  The telescope weighs 530 tons.  Yet, this colossal telescope, built when a computer was a slide-rule and a no.2 pencil, is able to put a star on the slit of a spectrograph nearly every time it executes a go-to.  I've seen it.  It's mind-blowing.
 


Ray Gralak
 

If you can't go at least a couple minutes unguided then your setup has a bad model, unmodeled flexure, or too much random error. There's nothing that modeling software can do to fix the last item. To get better performance with modeling software you may need to invest some time figuring out why some areas of the sky are not as accurate as others and fix the mechanical issues in those areas.

As for a 530 ton telescope, the modeling is going to be much more deterministic and repeatable because the weight of the instrument allows it to be impervious to outside factors. A tugging cable on your setup would probably be the equivalent to a multi-ton load on the Hale scope. :-)

-Ray Gralak
Author of APCC (Astro-Physics Command Center): http://www.astro-physics.com/index.htm?products/accessories/software/apcc/apcc
Author of PEMPro: http://www.ccdware.com
Author of Astro-Physics V2 ASCOM Driver: http://www.gralak.com/apdriver
Author of PulseGuide: http://www.pulseguide.com
Author of Sigma: http://www.gralak.com/sigma

-----Original Message-----
From: ap-gto@yahoogroups.com [mailto:ap-gto@yahoogroups.com]
Sent: Saturday, November 4, 2017 9:51 PM
To: ap-gto@yahoogroups.com
Subject: Re: [ap-gto] APPM error



The second question, about "custom tracking": yes, it's turned on in APCC. I had to go out to the observatory to
see what you were talking about. I'm using MaxIm DL 6.xx for guiding. The matter I was addressing was that I
don't see that APPM's sky model has improved my guiding. Maybe it has, but it's not very visible in the numbers I
see as the corrections roll by. But I think this exchange has established that there's probably not much more I
should expect from APPM's sky model.

The reason I've pursued this discussion more than once, as this topic recycles every few months in this forum, is
due to what I see at Palomar Observatory, where I work as a volunteer. There's a sky model in the software for
the 200-inch Hale Telescope. I think the model software was developed by a Caltech programmer. I don't think
it's one of the commercial products (e.g. T-Point or Pi npoint). I don't know what they did to establish the points of
the model. I've met the man who wrote it (I think), but I've never had a chance to discuss this software with him.
The pointing accuracy of the 200-inch is far beyond anything I see with my own gear. Cassegrain is the most
commonly used focus, f/16 or about 80m FL. The telescope weighs 530 tons. Yet, this colossal telescope, built
when a computer was a slide-rule and a no.2 pencil, is able to put a star on the slit of a spectrograph nearly every
time it executes a go-to. I've seen it. It's mind-blowing.



Tom Ellis
 

There is another plane that has not been discussed, it is verticality the error of which will increase with altitude.  Simply stated check the level of the mount.  Ray's program is gang busters.  So is TSX Tpoint.  If you are on a portable mount Tpoint will get you in the neighbood faster.  
aloha tom


Roland Christen
 


 The matter I was addressing was that I don't see that APPM's sky model has improved my guiding.  Maybe it has, but it's not very visible in the numbers I see as the corrections roll by.
My guiding with the 17" astrograph can vary enormously depending on seeing. I've had guiding values of less than 0.1 arc sec RMS and as much as 0.5 RMS on a different night. Star sizes vary from 0.9 arc sec FWHM on the very best night to 3.5 arc sec FWHM on the worst nights. And none of this has anything to do with the sky model.

Rolando


-----Original Message-----
From: calypte@... [ap-gto]
To: ap-gto
Sent: Sat, Nov 4, 2017 11:51 pm
Subject: Re: [ap-gto] APPM error



The second question, about "custom tracking": yes, it's turned on in APCC.  I had to go out to the observatory to see what you were talking about.  I'm using MaxIm DL 6.xx for guiding.  The matter I was addressing was that I don't see that APPM's sky model has improved my guiding.  Maybe it has, but it's not very visible in the numbers I see as the corrections roll by.  But I think this exchange has established that there's probably not much more I should expect from APPM's sky model.

The reason I've pursued this discussion more than once, as this topic recycles every few months in this forum, is due to what I see at Palomar Observatory, where I work as a volunteer.  There's a sky model in the software for the 200-inch Hale Telescope.  I think the model software was developed by a Caltech programmer.  I don't think it's one of the commercial products (e.g. T-Point or Pin point).  I don't know what they did to establish the points of the model.  I've met the man who wrote it (I think), but I've never had a chance to discuss this software with him.  The pointing accuracy of the 200-inch is far beyond anything I see with my own gear.  Cassegrain is the most commonly used focus, f/16 or about 80m FL.  The telescope weighs 530 tons.  Yet, this colossal telescope, built when a computer was a slide-rule and a no.2 pencil, is able to put a star on the slit of a spectrograph nearly every time it executes a go-to.  I've seen it.  It's mind-blowing.
 



Roland Christen
 


A tugging cable on your setup would probably be the equivalent to a multi-ton load on the Hale scope. :-)
And here is an interesting experiment I did recently. I set up an 1100 encoder mount with a 130 scope on it. The Renishaw absolute encoder coupled to the CP4 will try to keep the telescope axis to within 0.2 arc seconds of the commanded position, so any outside influence is instantly countered by the control loop. Pushing on the back of the scope causes the drive motors to "push back" against the outside force. I could see this while observing an artificial star with a high power crosshair eyepiece inserted in the camera's off-axis guider. While there was some flex of the telescope tube inside the felt lined rings, amounting to 3 to 5 arc sec, there was no movement of the star when I pushed on the cradle plate which is rigidly attached to the telescope axis. However, when I pushed on the camera, I saw movement of 20 to 30 arc seconds. After tightening down the focuser drawtube, this was reduced considerably, however not fully eliminated. So, we have a number of things in any setup that can produce subtle errors of pointing and tracking no matter how well we establish a model.

Rolando


-----Original Message-----
From: 'Ray Gralak (Groups)' groups3@... [ap-gto]
To: ap-gto
Sent: Sun, Nov 5, 2017 12:42 am
Subject: RE: [ap-gto] APPM error

If you can't go at least a couple minutes unguided then your setup has a bad model, unmodeled flexure, or too much random error. There's nothing that modeling software can do to fix the last item. To get better performance with modeling software you may need to invest some time figuring out why some areas of the sky are not as accurate as others and fix the mechanical issues in those areas.

As for a 530 ton telescope, the modeling is going to be much more deterministic and repeatable because the weight of the instrument allows it to be impervious to outside factors. A tugging cable on your setup would probably be the equivalent to a multi-ton load on the Hale scope. :-)

-Ray Gralak
Author of APCC (Astro-Physics Command Center): http://www.astro-physics.com/index.htm?products/accessories/software/apcc/apcc
Author of PEMPro: http://www.ccdware.com
Author of Astro-Physics V2 ASCOM Driver: http://www.gralak.com/apdriver
Author of PulseGuide: http://www.pulseguide.com
Author of Sigma: http://www.gralak.com/sigma


> -----Original Message-----
> From: ap-gto@... [mailto:ap-gto@...]
> Sent: Saturday, November 4, 2017 9:51 PM
> To: ap-gto@...
> Subject: Re: [ap-gto] APPM error
>
>
>
> The second question, about "custom tracking": yes, it's turned on in APCC. I had to go out to the observatory to
> see what you were talking about. I'm using MaxIm DL 6.xx for guiding. The matter I was addressing was that I
> don't see that APPM's sky model has improved my guiding. Maybe it has, but it's not very visible in the numbers I
> see as the corrections roll by. But I think this exchange has established that there's probably not much more I
> should expect from APPM's sky model.
>
> The reason I've pursued this discussion more than once, as this topic recycles every few months in this forum, is
> due to what I see at Palomar Observatory, where I work as a volunteer. There's a sky model in the software for
> the 200-inch Hale Telescope. I think the model software was developed by a Caltech programmer. I don't think
> it's one of the commercial products (e.g. T-Point or Pi npoint). I don't know what they did to establish the points of
> the model. I've met the man who wrote it (I think), but I've never had a chance to discuss this software with him.
> The pointing accuracy of the 200-inch is far beyond anything I see with my own gear. Cassegrain is the most
> commonly used focus, f/16 or about 80m FL. The telescope weighs 530 tons. Yet, this colossal telescope, built
> when a computer was a slide-rule and a no.2 pencil, is able to put a star on the slit of a spectrograph nearly every
> time it executes a go-to. I've seen it. It's mind-blowing.
>
>
>



------------------------------------
Posted by: "Ray Gralak \(Groups\)" <groups3@...>
------------------------------------

To UNSUBSCRIBE, or for general information on the ap-gto list
see http://groups.yahoo.com/group/ap-gto
------------------------------------

Yahoo Groups Links

<*> To visit your group on the web, go to:
http://groups.yahoo.com/group/ap-gto/

<*> Your email settings:
Individual Email | Traditional

<*> To change settings online go to:
http://groups.yahoo.com/group/ap-gto/join
(Yahoo! ID required)

<*> To change settings via email:
ap-gto-digest@...
ap-gto-fullfeatured@...

<*> To unsubscribe from this group, send an email to:
ap-gto-unsubscribe@...

<*> Your use of Yahoo Groups is subject to:
https://info.yahoo.com/legal/us/yahoo/utos/terms/