Date   

Re: Understanding APPM and Recals

Ray Gralak
 

Hi Marty,

I am trying to build an APPM model for my f/10 Cassegrain, now using a mono imaging setup with a 0.40 image
scale and variations on 1x1 and 2x2 binning, all with limited success. This leads to two questions.
Can you provide ALL of your APPM logs and PNT files, so that I can look through them? You can use the APCC log zipper utility. For now, I don't need APCC or ASCOM logs, so you can exclude them.

First, could I be getting spurious results? APPM keeps telling me that my telescope on the west side is off in RA by
as much as 12 degrees. This seems very strange. Twelve degrees is a lot. I've checked for cone error and it is
under 8 arc-minutes. The errors are only in RA, not DEC. The mirrors in the Cassegrain are fixed -- no mirror flop.
The model on the East side is far better -- pointing is off by 5-15 arc-minutes. What explanations are there for
such high pointing errors on one side (only) of the meridian? Could this be a result of my settings leading to
spurious solutions? Only about half of the model points result in a solution anyway. Note that I've done this twice,
with two different cameras, and got similar results.
12 degrees is a lot. Are you seeing that level of error consistently?

After you install the model, is pointing bad on both sides, or just the side with high errors?

How does a Platesolve/Recal executed through APPM work in cases where an APPM-built model is in already
place and in use? Does it modify the underlying APPM model in any way or just make a one-time adjustment for
where the telescope is at that moment pointing? Would that adjustment carry over to other pointing on that same
side of the meridian? In other words, can I gradually refine an APPM model by a series of Platesolve/Recals and
then save it as a new model?
PlateSolve/Recals do not add or refine the pointing model.

Similarly, how does a Recal ("Sync") work in TSX relative to an APPM model? I assume it doesn't change the
underlying APPM model at all. But will it apply the Sync adjustment to all pointing positions on that same side of
the meridian?
TSX Sync's will not change the pointing model.

-Ray


Understanding APPM and Recals

mjb87@...
 

I am trying to build an APPM model for my f/10 Cassegrain, now using a mono imaging setup with a 0.40 image scale and variations on 1x1 and 2x2 binning, all with limited success. This leads to two questions.

First, could I be getting spurious results? APPM keeps telling me that my telescope on the west side is off in RA by as much as 12 degrees. This seems very strange. Twelve degrees is a lot. I've checked for cone error and it is under 8 arc-minutes. The errors are only in RA, not DEC. The mirrors in the Cassegrain are fixed -- no mirror flop. The model on the East side is far better -- pointing is off by 5-15 arc-minutes.  What explanations are there for such high pointing errors on one side (only) of the meridian? Could this be a result of my settings leading to spurious solutions? Only about half of the model points result in a solution anyway. Note that I've done this twice, with two different cameras, and got similar results.

One option to give up on an automated camera solution and build, instead, a T-point model manually with 20-30 points.  I'm not worried about tracking accuracy in this setup as much as pointing accuracy. I then wondered if I couldn't build an APPM model "manually" with a series of Platesolves/Recals. This leads to a second set of questions about how APPM models behave...

How does a Platesolve/Recal executed through APPM work in cases where an APPM-built model is in already place and in use? Does it modify the underlying APPM model in any way or just make a one-time adjustment for where the telescope is at that moment pointing?  Would that adjustment carry over to other pointing on that same side of the meridian? In other words, can I gradually refine an APPM model by a series of Platesolve/Recals and then save it as a new model?

Similarly, how does a Recal ("Sync") work in TSX relative to an APPM model? I assume it doesn't change the underlying APPM model at all. But will it apply the Sync adjustment to all pointing positions on that same side of the meridian?

Thanks.


Re: Software Enhancement Requests Process?

 

There isn’t now, but we are planning one soon.

 

Clear Skies,

Marj Christen

Astro-Physics

11250 Forest Hills Road

Machesney Park, IL 61115

Phone: 815-282-1513

www.astro-physics.com

 

From: main@ap-gto.groups.io <main@ap-gto.groups.io> On Behalf Of Brent Boshart
Sent: Monday, May 17, 2021 12:56 PM
To: main@ap-gto.groups.io
Subject: [ap-gto] Software Enhancement Requests Process?

 

Is there is a formal process for submitting software enhancement requests for the AP ASCOM driver or APCC?  Thanks.


Re: Connecting ASIAIR Pro to a CP4 - Mach1

Kevin Cook
 

Hi Lee - You touched on two of my frustrations in using the ASIAIR PRO with my older Mach 1 mount (CP3).  I agree the guiding using the ASIAIR's PhD-lite is substandard compared to what the mount can do using the full version of PhD2.  I think the ASIAIR's PhD-Lite simply lacks the controls and the guiding assistant to optimize performance with the Mach 1 mount.  I am cautiously optimistic the soon-to-be-released multistar guiding for the ASIAIR will resolve some of our problems.

I have the same problem with the ASIAIR not recognizing the HOME position for my mount (I use Park 3).  After doing the polar alignment routine where the ASIAIR rotates the mount 60 degrees or so, it hardly ever returns to the HOME position when I tell it to do so.  I usually have to loosen the clutches, manually move the mount back to the Park 3 position, then cycle the power to the mount off and then back on.  Even that does not always work.  Sometimes I have better success doing the first GOTO to a target immediately after completing the polar alignment, without attempting to return to HOME first.  I will try your approach the next time I get the mount and scope set up.  

I have another ASIAIR-Mach 1 workaround that is related to the process you outlined about the home position.  I like to start my imaging runs with the target an hour or two east of the meridian and then track through the meridian without having to do a meridian flip.  Unfortunately, the ASIAIR software always wants to position the scope on the "correct" side of the mount (i.e., scope up, counterweights down) even when the target is very close to crossing the meridian and necessitating a meridian flip.  So here is my workaround:
  • Let's assume the target is M51, high in the evening sky this time of year but east of the meridian.  The initial ASIAIR GOTO (refined with plate solving) will place the scope on the west side of the mount, looking east toward the target.
  • Next select that target (say M51) on the AP hand controller.  Do not press GOTO on the hand controller, but instead use the right arrow key (labelled NEXT on the hand controller) to SYNC to that target.  At this point, the mount has not moved from where the ASIAIR positioned it, but the mount now knows it is looking at M51.
  • Using the meridian delay function on the Mach 1, press the RA/DEC/REV key on the AP keypad and using the NEXT arrow key on the keypad, select a meridian "advance" of 2 hours east.  This will allow the Mach 1 to acquire the target up to 2 hours east of the meridian, but with the scope on the east side and lower than the counterweights.
  • Now select the target M51 again on the hand controller and this time press GOTO so the Mach 1 slews to the target with the scope in the desired position.
  • Take a short preview exposure using the ASIAIR and have it plate solve that image.  The scope should be pointing close enough to the target for an easy plate solve.  Once completed, select Go to Target and Sync Mount on the ASIAIR control panel.  Done.  Now the mount starts with the scope positioned how I want it and seamlessly tracks the target through the meridian.  
  • Obviously, a variation of this process allows one to acquire a target earlier in the eastern sky, with the scope "correctly" positioned, and then using the AP keypad to instruct a meridian delay, the mount will track through the meridian, with the scope in the "incorrect" scope down/counterweights up position for another hour or two.
Kevin Cook


On Sun, May 16, 2021 at 8:43 AM Lee Decovnick <ursa@...> wrote:
Just an update on the ASI AIR Pro and the  Mach 1( CP4) ..The Raspberry Pi software/plate solve in the AAP does a wonderful job of polar alignment .. After two iterations of PA ,I checked it against SharpCap and RAPAS and it was dead- on with both. More importantly I was doing three minutes subs without guiding and saw nice round stars.  The AAP (PhD 2 light) auto guider is just ...um...ok... a bit of patience/ frustration to get the aggressiveness correct and the other setting needed more than bit of tweaking.

So to answer the question I asked above about resetting  to Park...The 'trick" is after you PA, do a long GOTO to the West side of the mount, plate solve, hit sync in AAP and got to park on the AAP. You'll be a bit or a lot off.. open the clutches and manually  move the mount to the Park position of you choice  and tighten the clutches. Do a long GOTO East, plate solve,  and back to Park and open and close the clutches again to get the mark lined up perfectly. I have hit every GOTO right in the middle of the camera's field of view since then.  And even after shutting off the CP4 and AAP, the postitioning/ GOTO was perfect two nights later.

I posted my first light pic at Lee D. Photos


Re: AP1100, Berlebach Planet, mounting CP4

ap@CaptivePhotons.com
 

  • I have both an 1100 and a tripod so I will set them up and see what the clearances are both ways.

 

While I certainly appreciate any info, please do not go to a lot of trouble.   You guys have a lot on your plates!

 


Re: AP1100, Berlebach Planet, mounting CP4

Roland Christen
 

I have both an 1100 and a tripod so I will set them up and see what the clearances are both ways.

Roland

-----Original Message-----
From: ap@... <ap@...>
To: main@ap-gto.groups.io <main@ap-gto.groups.io>
Sent: Tue, May 18, 2021 11:47 am
Subject: Re: [ap-gto] AP1100, Berlebach Planet, mounting CP4

>>> Roland said:
 
Whether you put the 3rd leg pointing North or pointing South, the clearance of the other two legs will be about the same. In fact, you will have slightly more clearance for the telescopes when pointing at the zenith because the 1100 Dec axis hangs more northward of center. It is also the most stable condition for the mount with just counterweights attached.
 
That would be great if the clearance is better, as I do not really WANT to put the single leg south.  But with both my old CEM70G and current MyT that did give me several inches more clearance, enough I had no risk of collision (so long as I paid a bit of attention to rotation angle of the filter wheel), but definitely had collisions otherwise.
 
But if I can put the single leg North and still not have a collision issue, that would be terrific, as that almost doubles the available supported CG position.
 
Thank you.
 

--
Roland Christen
Astro-Physics


Re: AP1100, Berlebach Planet, mounting CP4

Roland Christen
 

I should have added that with the 3rd leg pointed northward, there is slightly more clearance for the telescope when it is pointing to the zenith.

Rolando



-----Original Message-----
From: Roland Christen via groups.io <chris1011@...>
To: main@ap-gto.groups.io <main@ap-gto.groups.io>
Sent: Tue, May 18, 2021 11:18 am
Subject: Re: [ap-gto] AP1100, Berlebach Planet, mounting CP4

Whether you put the 3rd leg pointing North or pointing South, the clearance of the other two legs will be about the same. In fact, you will have slightly more clearance for the telescopes when pointing at the zenith because the 1100 Dec axis hangs more northward of center. It is also the most stable condition for the mount with just counterweights attached.

Roland

-----Original Message-----
From: ap@... <ap@...>
To: main@ap-gto.groups.io
Sent: Tue, May 18, 2021 10:54 am
Subject: Re: [ap-gto] AP1100, Berlebach Planet, mounting CP4

As a follow on question with a Berlebach planet.

I received the mounting ring from Berlebach, and it emphasized how large the base of the AP1100 will be in comparison to this tripod.

I do not plan to have more than about 45 pounds of OTA, and counterweights of course. 

Does anyone with a similar setup have any kind of idea where the center of gravity is for that kind of setup?  Specifically how far off center?  

I typically image with the legs retracted fully for stability, and legs at closest are 9.5" (between legs) and 17" (at a single leg) from center.  I prefer to image with the single leg south not north, this provides a LOT more clearance (at least on my MyT) near zenith to avoid leg crashes.  But when I looked at that 9.5" it made me worry, this is a larger mount and probably different CG.

I found the Dimension Calculator spreadsheet, clearly aimed at clearance not load.  But I think (emphasis on think) that the point in the first image labeled as offset B, represents the BALANCED CG, basically at the intersection with the DEC axis.  

But what I am worried about is the unbalanced CG -- the point at which I have loaded 50# or so of counterweights and have yet to attach the OTA.  I.e. the situation why everyone says "put the single leg under the counterweight shaft".  Which is good advice I hope to not have to take so I don't hit the legs with my imaging train.

This all works fine on the MyT, it is quite stable.  But worried -- am I in for a rude surprise with the larger AP1100 (with 45# load)?  Yes, this is easy to figure out once I get it -- but if I need a new tripod/pier I'd like to get it on order now.

Anyone know where the CG is going to land?   And yes, I realize it's latitude dependent (I'm at 26d) but any real world experience welcome.

Linwood

--
Roland Christen
Astro-Physics

--
Roland Christen
Astro-Physics


Re: AP1100, Berlebach Planet, mounting CP4

ap@CaptivePhotons.com
 

>>> Roland said:

 

Whether you put the 3rd leg pointing North or pointing South, the clearance of the other two legs will be about the same. In fact, you will have slightly more clearance for the telescopes when pointing at the zenith because the 1100 Dec axis hangs more northward of center. It is also the most stable condition for the mount with just counterweights attached.

 

That would be great if the clearance is better, as I do not really WANT to put the single leg south.  But with both my old CEM70G and current MyT that did give me several inches more clearance, enough I had no risk of collision (so long as I paid a bit of attention to rotation angle of the filter wheel), but definitely had collisions otherwise.

 

But if I can put the single leg North and still not have a collision issue, that would be terrific, as that almost doubles the available supported CG position.

 

Thank you.

 


Re: Chasing a StarLink Satellite

Ray Gralak
 

Hi Brent,

Actually, you can turn off the caching of RA/Dec in APCC, but the option is not available in the user interface. APCC comes with an application called Horizons, which can track moving celestial objects and artificial satellites. Horizons turns off APCC caching when it is connected to the mount.

-Ray

-----Original Message-----
From: main@ap-gto.groups.io [mailto:main@ap-gto.groups.io] On Behalf Of Brent Boshart
Sent: Tuesday, May 18, 2021 9:08 AM
To: main@ap-gto.groups.io
Subject: Re: [ap-gto] Chasing a StarLink Satellite

This is awesome! Was this with SkyTrack connected to the Mach2 via AP ASCOM driver or did you write a direct
interface?

That is with a direct interface. Unfortunately currently both the AP ASCOM driver and APCC have a limitation that
makes this accurate of tracking not possible. I use a loop that calculates difference between the satellite current
position and the mount's position to make small adjustments to the satellite's rate of movement in order to keep it
centered. Both the ASCOM driver and APCC poll the mount about once every second for its position instead of
sending "real time" data when its requested - fine for most applications. So if I am slewing at 3 deg/sec the
position I get from ASCOM/APCC could be a full second old and off by 3 degrees. My FOV in this video is only 1
degree. You can see in the video it does not stay exactly centered, that is pointing error because I only did a one
star sync for alignment. It would be nice to be able to use the APCC modelling. According to the position data I
receive comparing to the calculated satellite position, I am able to keep the satellite within 0.5 arcminutes of center,
the rest is calibration/pointing error.


Re: AP1100, Berlebach Planet, mounting CP4

Roland Christen
 

Whether you put the 3rd leg pointing North or pointing South, the clearance of the other two legs will be about the same. In fact, you will have slightly more clearance for the telescopes when pointing at the zenith because the 1100 Dec axis hangs more northward of center. It is also the most stable condition for the mount with just counterweights attached.

Roland

-----Original Message-----
From: ap@... <ap@...>
To: main@ap-gto.groups.io
Sent: Tue, May 18, 2021 10:54 am
Subject: Re: [ap-gto] AP1100, Berlebach Planet, mounting CP4

As a follow on question with a Berlebach planet.

I received the mounting ring from Berlebach, and it emphasized how large the base of the AP1100 will be in comparison to this tripod.

I do not plan to have more than about 45 pounds of OTA, and counterweights of course. 

Does anyone with a similar setup have any kind of idea where the center of gravity is for that kind of setup?  Specifically how far off center?  

I typically image with the legs retracted fully for stability, and legs at closest are 9.5" (between legs) and 17" (at a single leg) from center.  I prefer to image with the single leg south not north, this provides a LOT more clearance (at least on my MyT) near zenith to avoid leg crashes.  But when I looked at that 9.5" it made me worry, this is a larger mount and probably different CG.

I found the Dimension Calculator spreadsheet, clearly aimed at clearance not load.  But I think (emphasis on think) that the point in the first image labeled as offset B, represents the BALANCED CG, basically at the intersection with the DEC axis.  

But what I am worried about is the unbalanced CG -- the point at which I have loaded 50# or so of counterweights and have yet to attach the OTA.  I.e. the situation why everyone says "put the single leg under the counterweight shaft".  Which is good advice I hope to not have to take so I don't hit the legs with my imaging train.

This all works fine on the MyT, it is quite stable.  But worried -- am I in for a rude surprise with the larger AP1100 (with 45# load)?  Yes, this is easy to figure out once I get it -- but if I need a new tripod/pier I'd like to get it on order now.

Anyone know where the CG is going to land?   And yes, I realize it's latitude dependent (I'm at 26d) but any real world experience welcome.

Linwood

--
Roland Christen
Astro-Physics


Re: Chasing a StarLink Satellite

Brent Boshart
 

> This is awesome! Was this with SkyTrack connected to the Mach2 via AP ASCOM driver or did you write a direct interface?

That is with a direct interface.  Unfortunately currently both the AP ASCOM driver and APCC have a limitation that makes this accurate of tracking not possible.  I use a loop that calculates difference between the satellite current position and the mount's position to make small adjustments to the satellite's rate of movement in order to keep it centered. Both the ASCOM driver and APCC poll the mount about once every second for its position instead of sending "real time" data when its requested - fine for most applications.  So if I am slewing at 3 deg/sec the position I get from ASCOM/APCC could be a full second old and off by 3 degrees.  My FOV in this video is only 1 degree.  You can see in the video it does not stay exactly centered, that is pointing error because I only did a one star sync for alignment. It would be nice to be able to use the APCC modelling.  According to the position data I receive comparing to the calculated satellite position, I am able to keep the satellite within 0.5 arcminutes of center, the rest is calibration/pointing error.


Re: AP1100, Berlebach Planet, mounting CP4

ap@CaptivePhotons.com
 

As a follow on question with a Berlebach planet.

I received the mounting ring from Berlebach, and it emphasized how large the base of the AP1100 will be in comparison to this tripod.

I do not plan to have more than about 45 pounds of OTA, and counterweights of course. 

Does anyone with a similar setup have any kind of idea where the center of gravity is for that kind of setup?  Specifically how far off center?  

I typically image with the legs retracted fully for stability, and legs at closest are 9.5" (between legs) and 17" (at a single leg) from center.  I prefer to image with the single leg south not north, this provides a LOT more clearance (at least on my MyT) near zenith to avoid leg crashes.  But when I looked at that 9.5" it made me worry, this is a larger mount and probably different CG.

I found the Dimension Calculator spreadsheet, clearly aimed at clearance not load.  But I think (emphasis on think) that the point in the first image labeled as offset B, represents the BALANCED CG, basically at the intersection with the DEC axis.  

But what I am worried about is the unbalanced CG -- the point at which I have loaded 50# or so of counterweights and have yet to attach the OTA.  I.e. the situation why everyone says "put the single leg under the counterweight shaft".  Which is good advice I hope to not have to take so I don't hit the legs with my imaging train.

This all works fine on the MyT, it is quite stable.  But worried -- am I in for a rude surprise with the larger AP1100 (with 45# load)?  Yes, this is easy to figure out once I get it -- but if I need a new tripod/pier I'd like to get it on order now.

Anyone know where the CG is going to land?   And yes, I realize it's latitude dependent (I'm at 26d) but any real world experience welcome.

Linwood


Re: Chasing a StarLink Satellite

Luca Marinelli
 

Hi Brent,

 

This is awesome! Was this with SkyTrack connected to the Mach2 via AP ASCOM driver or did you write a direct interface?

 

Really nice work!

 

Luca

 

From: main@ap-gto.groups.io <main@ap-gto.groups.io> On Behalf Of Brent Boshart via groups.io
Sent: Tuesday, May 18, 2021 7:20 AM
To: main@ap-gto.groups.io
Subject: Re: [ap-gto] Chasing a StarLink Satellite

 

[Edited Message Follows]

> How is the gamepad wired up?

The gamepad is not wired to the mount. It provides input to the software that calculates the satellite position.


Re: Chasing a StarLink Satellite

Roland Christen
 

WoW, super! Looks like the little satellite is dodging incoming missiles. Smile

Rolando


-----Original Message-----
From: Brent Boshart <bboshart@...>
To: main@ap-gto.groups.io
Sent: Tue, May 18, 2021 12:28 am
Subject: [ap-gto] Chasing a StarLink Satellite

First night out with my Mach2.  How is this for different - a StarLink satellite is a tight round dot and the stars are streaks... :)   The perpendicular movement at 00:24 is me making an adjustment with a gamepad - how fun is that?  Near the end of the video clip you can see the StarLink rotate. I'm looking forward to an ISS pass. 

https://www.youtube.com/watch?v=kDiPO-QuHPE

--
Roland Christen
Astro-Physics


Re: Chasing a StarLink Satellite

Karen Christen
 

That’s really fun.  It’s fascinating to see what folks can do with our equipment.  Thanks so much for sharing your video, Brent!

Karen

AP

 

From: main@ap-gto.groups.io <main@ap-gto.groups.io> On Behalf Of Brent Boshart
Sent: Tuesday, May 18, 2021 12:28 AM
To: main@ap-gto.groups.io
Subject: [ap-gto] Chasing a StarLink Satellite

 

First night out with my Mach2.  How is this for different - a StarLink satellite is a tight round dot and the stars are streaks... :)   The perpendicular movement at 00:24 is me making an adjustment with a gamepad - how fun is that?  Near the end of the video clip you can see the StarLink rotate. I'm looking forward to an ISS pass. 

https://www.youtube.com/watch?v=kDiPO-QuHPE


--
Karen Christen
Astro-Physics


Re: Chasing a StarLink Satellite

Dean Jacobsen
 

Nice Brent!  It looks like you are making excellent progress on the project.
--
Dean Jacobsen
Astrobin Image Gallery - https://www.astrobin.com/users/deanjacobsen/


Re: Chasing a StarLink Satellite

Brent Boshart
 
Edited

> How is the gamepad wired up?

The gamepad is not wired to the mount. It provides input to the software that calculates the satellite position.


Re: Chasing a StarLink Satellite

Jeffc
 

> making an adjustment with a gamepad

How is the gamepad wired up?

Fwiw, I've been using APPC "remote" with a laptop.
When I need to do something at the mount (e.g. last night for some reason I had to "re-initialize / calibrate"), it is a bit awkward to "push the buttons on the control window"... sure the laptop is wifi and very portable, but it is awkward to look through the viewfinder while pushing a virtual button using the trackpad.

I do have an AP keypad, but i rarely use it as I'm mostly / always using APCC these days.

Having a simple gamepad at the mount would be useful when I occasionally need to move the scope to center an object in the viewfinder.

Btw, I have a celestron four button keypad with RJ12 connector.. I've wondered if I can plug this into the guide port, set the rate appropriately, and use it for minor moves.

-jeff


On Mon, May 17, 2021 at 10:28 PM Brent Boshart <bboshart@...> wrote:
First night out with my Mach2.  How is this for different - a StarLink satellite is a tight round dot and the stars are streaks... :)   The perpendicular movement at 00:24 is me making an adjustment with a gamepad - how fun is that?  Near the end of the video clip you can see the StarLink rotate. I'm looking forward to an ISS pass. 

https://www.youtube.com/watch?v=kDiPO-QuHPE


Re: Chasing a StarLink Satellite

Christopher Erickson
 

Way cool!

-Christopher Erickson
Observatory Engineer
Summit Kinetics
Waikoloa, Hawaii


Virus-free. www.avg.com


On Mon, May 17, 2021 at 7:28 PM Brent Boshart <bboshart@...> wrote:
First night out with my Mach2.  How is this for different - a StarLink satellite is a tight round dot and the stars are streaks... :)   The perpendicular movement at 00:24 is me making an adjustment with a gamepad - how fun is that?  Near the end of the video clip you can see the StarLink rotate. I'm looking forward to an ISS pass. 

https://www.youtube.com/watch?v=kDiPO-QuHPE


Chasing a StarLink Satellite

Brent Boshart
 

First night out with my Mach2.  How is this for different - a StarLink satellite is a tight round dot and the stars are streaks... :)   The perpendicular movement at 00:24 is me making an adjustment with a gamepad - how fun is that?  Near the end of the video clip you can see the StarLink rotate. I'm looking forward to an ISS pass. 

https://www.youtube.com/watch?v=kDiPO-QuHPE

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