APPM at low temperatures


Tom Blahovici
 

Hi
I have noticed that as the temperature drops here in Canada, my pointing accuracy seems to be getting worse.
In addition, when I start everything up, and try to do a plate  solve and sync in APPM it always fails.
So for the first observation, I do use an MGBox so I would think this has corrections. I did the model at around 8C. Current observing conditions put the mount at -25C.

For the second case, when I do the plate solve and sync,the stars are somewhat out of focus since the temperature is at the beggining of the night and the focus position was from  late at night. It always fails even with a whole sky plate solve. On the other hand, if I then go into TheSkyX, take a photo and do the all sky image link it works perfectly. What gives with that?
Thanks, Tom


Ray Gralak
 

Hi Tom,

Refraction is not the only thing affected by temperature shifts. For example, the scope becomes less flexible, and the colder ground might shift polar alignment. If the model is not working as well, then try building a new model and comparing the pointing terms to see what has changed.

Regarding failed plate solves, then check the configuration in SkyX as per the APCC help file. In particular, there are additional settings for external plate solving. Also, make sure that SkyX is connected to the mount through the AP V2 driver so that the plate-solve sky position is known to SkyX.

-Ray

-----Original Message-----
From: main@ap-gto.groups.io [mailto:main@ap-gto.groups.io] On Behalf Of Tom Blahovici
Sent: Monday, January 24, 2022 8:31 AM
To: main@ap-gto.groups.io
Subject: [ap-gto] APPM at low temperatures

Hi
I have noticed that as the temperature drops here in Canada, my pointing accuracy seems to be getting worse.
In addition, when I start everything up, and try to do a plate solve and sync in APPM it always fails.
So for the first observation, I do use an MGBox so I would think this has corrections. I did the model at
around 8C. Current observing conditions put the mount at -25C.

For the second case, when I do the plate solve and sync,the stars are somewhat out of focus since the
temperature is at the beggining of the night and the focus position was from late at night. It always fails even
with a whole sky plate solve. On the other hand, if I then go into TheSkyX, take a photo and do the all sky
image link it works perfectly. What gives with that?
Thanks, Tom


Tom Blahovici
 

Hi Ray. Ok.
All makes sense. 
-25C would be likely to affect polar alignment even though I have a 6foot deep column of concrete.

Best regards, Tom


Tom Blahovici
 

One thing. Would it not be possible to connect TheSkyX to the ascom driver automatically when appm connects to TheSkyX? Otherwise this is just an additional step. I would just open thesky and do it all there.
Possibly a future enhancement?
Tom


Brent Boshart
 

Hi Tom,

My model seems to do ok over a wide temperature range (0c to -22c), but when the frost sets in, it does move my 5ft deep pier a little (polar align went from about 1.5 arcmin to 5 arcmin error).  I adjusted my polar alignment and rebuilt my model after frost. 

Brent


Roland Christen
 

When I open SkyX and press "Connect", it automatically brings up APCC and the ASCOM driver. There are no additional steps.

Rolando

-----Original Message-----
From: Tom Blahovici <tom.va2fsq@...>
To: main@ap-gto.groups.io
Sent: Mon, Jan 24, 2022 1:45 pm
Subject: Re: [ap-gto] APPM at low temperatures

One thing. Would it not be possible to connect TheSkyX to the ascom driver automatically when appm connects to TheSkyX? Otherwise this is just an additional step. I would just open thesky and do it all there.
Possibly a future enhancement?
Tom

--
Roland Christen
Astro-Physics


Tom Blahovici
 

That's not what I meant.  I'm talking about doing a sync with APPM.  When you open appm, you can connect to the sky and the mount, but  that does not automatically start the mount in the sky as Ray suggested I do.  So it means I need to go into the sky and connect the mount. After all that it is just easier to use the sky to sync without appm.
  Perhaps this is an option in the sky to automatically start the ascom driver when an outside program launches the program to use its camera?  Haven't found it.
Tom


Ray Gralak
 

Hi Tom,

I'll have to see if that would be feasible. Neither APCC nor APPM needs to connect to TheSky's Telescope driver, and if TheSky is not set up correctly it may produce errors that could stop the plate-solving process. I think it's more deterministic to manually start SkyX and connect to the mount. This ensures that SkyX is configured correctly if you see the connection to the mount is successful.

-Ray

-----Original Message-----
From: main@ap-gto.groups.io [mailto:main@ap-gto.groups.io] On Behalf Of Tom Blahovici
Sent: Monday, January 24, 2022 7:36 PM
To: main@ap-gto.groups.io
Subject: Re: [ap-gto] APPM at low temperatures

That's not what I meant. I'm talking about doing a sync with APPM. When you open appm, you can connect
to the sky and the mount, but that does not automatically start the mount in the sky as Ray suggested I do.
So it means I need to go into the sky and connect the mount. After all that it is just easier to use the sky to
sync without appm.
Perhaps this is an option in the sky to automatically start the ascom driver when an outside program
launches the program to use its camera? Haven't found it.
Tom


Tom Blahovici
 

Hi
I can confirm that the appm plate solve and sync works fine as long as you first connect to a mount driver in the sky.
However, I still wonder why this is necessary.
For example in Voyager, a precise pointing will slew the mount, take a photo with the sky x, and then plate solve and sync without issue. In this case the mount is NOT connected in TheSkyX.
So of it works there, why not when connected via appm?
Tom


Ray Gralak
 

Hi Tom,

For example in Voyager, a precise pointing will slew the mount, take a photo with the sky x, and then plate
solve and sync without issue. In this case the mount is NOT connected in TheSkyX.
So of it works there, why not when connected via appm?
It could be that Voyager is asking for an all-sky solve. Or, there is are FITS header keywords that SkyX needs to establish mount RA/Dec. APPM should be putting in all of the standard FITS keywords, so maybe you can post an image that doesn't solve so I can look at the FITS header.

-Ray

-----Original Message-----
From: main@ap-gto.groups.io [mailto:main@ap-gto.groups.io] On Behalf Of Tom Blahovici
Sent: Wednesday, January 26, 2022 10:45 AM
To: main@ap-gto.groups.io
Subject: Re: [ap-gto] APPM at low temperatures

Hi
I can confirm that the appm plate solve and sync works fine as long as you first connect to a mount driver in
the sky.
However, I still wonder why this is necessary.
For example in Voyager, a precise pointing will slew the mount, take a photo with the sky x, and then plate
solve and sync without issue. In this case the mount is NOT connected in TheSkyX.
So of it works there, why not when connected via appm?
Tom


Tom Blahovici
 

Hi
Well, when appm doesn't work with a plate solve and decal, it also won't with a all sky solve. Voyager never uses an l sky solve as well.
I will post the fits headers next time this happens.
Thanks.


Tom Blahovici
 

Hi Ray,
Where would I find such an image? If I just open APCC and then APPM and do a recal, where is the resulting image stored?
Thanks


Tom Blahovici
 

I should mention that it's not a big deal to go into the skyx and connect the mount before APPM does its recal however there is an issue with this if you use Voyager.
The problem is if Voyager is then started, it will fail trying to connect to the astro-physics mount.  One must close TheSkyX and wait a while before starting Voyager.
Even then, I find that sometimes Voyager will not start the mount connection, even though all are shown as closed in APCC.
Sometimes I even have to close APCC and start all over.
So passing the right information to the SkyX plate solve from the beginning would be much more efficient and trouble free.
Tom


Ray Gralak
 

Where would I find such an image? If I just open APCC and then APPM and do a recal, where is the resulting
image stored?
My Documents\Astro-Physics\APPM

-Ray

-----Original Message-----
From: main@ap-gto.groups.io [mailto:main@ap-gto.groups.io] On Behalf Of Tom Blahovici
Sent: Saturday, March 5, 2022 2:58 PM
To: main@ap-gto.groups.io
Subject: Re: [ap-gto] APPM at low temperatures

Hi Ray,
Where would I find such an image? If I just open APCC and then APPM and do a recal, where is the resulting
image stored?
Thanks


Ray Gralak
 

Tom,


So passing the right information to the SkyX plate solve from the beginning would be much more efficient and
trouble free.
There is no way to pass information to SkyX except through the FITS header. If the mount is not connected then RA and Dec won't make it into the FITS header.

-Ray

-----Original Message-----
From: main@ap-gto.groups.io [mailto:main@ap-gto.groups.io] On Behalf Of Tom Blahovici
Sent: Saturday, March 5, 2022 3:04 PM
To: main@ap-gto.groups.io
Subject: Re: [ap-gto] APPM at low temperatures

I should mention that it's not a big deal to go into the skyx and connect the mount before APPM does its recal
however there is an issue with this if you use Voyager.
The problem is if Voyager is then started, it will fail trying to connect to the astro-physics mount. One must close
TheSkyX and wait a while before starting Voyager.
Even then, I find that sometimes Voyager will not start the mount connection, even though all are shown as
closed in APCC.
Sometimes I even have to close APCC and start all over.
So passing the right information to the SkyX plate solve from the beginning would be much more efficient and
trouble free.
Tom


Tom Blahovici
 

Hi
"There is no way to pass information to SkyX except through the FITS header. If the mount is not connected then RA and Dec won't make it into the FITS header"

Ok. Then there is definitely something wrong with how appm does the platsolve and recalc. As I mentioned, in Voyager, the mount is NOT connected in the skyx at all and plateesolves work perfectly. 
The next time I am out, I will find the skyx image and that from Voyager and compare the fits headers.
Tom


Ray Gralak
 

Hi Tom,

I don't recall the details of how you are connecting the camera in APPM, but if you are using SKyX's Camera control and SkyX is not connected to the mount, then there is no way for SkyX to insert RA/Dec into the image's FITS header. Voyager may be modifying SkyX's FITS header before providing it to the SkyX for plate solving. APPM does not do that, but I don't consider that a bug because APPM requires SkyX to be connected to the mount specifically so that APPM does NOT have to modify the FITS header (for faster processing).

If you have a different configuration, then please remind me.

-Ray

-----Original Message-----
From: main@ap-gto.groups.io [mailto:main@ap-gto.groups.io] On Behalf Of Tom Blahovici
Sent: Sunday, March 6, 2022 7:21 AM
To: main@ap-gto.groups.io
Subject: Re: [ap-gto] APPM at low temperatures

Hi
"There is no way to pass information to SkyX except through the FITS header. If the mount is not connected then
RA and Dec won't make it into the FITS header"

Ok. Then there is definitely something wrong with how appm does the platsolve and recalc. As I mentioned, in
Voyager, the mount is NOT connected in the skyx at all and plateesolves work perfectly.
The next time I am out, I will find the skyx image and that from Voyager and compare the fits headers.
Tom