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AP900 CP4 with ASIAIR - need some guidance

Dan_Paris
 

   Hi everyone,

since yesterday I am a happy owner of an AP900 with CP4 upgrade. What a beautiful an impressive mount! 

Coming from a Skywatcher AZ-EQ6 driven by an ASIAIR using EQMOD, I tried to use the AP900 in the same way.

I connected the ASIAIR to the CP4 with an USB cable, an turned everything on. After choosing "Astro-physics CP3/CP4" in the mount menu of the ASIAIR, the mount was instantly recognized and reacted to the arrow buttons on the phone screen. So far so good.  I then tried to simulate a full imaging session.  Everything eventually worked but there was some oddities:

  1. When I ran the polar alignement procedure, after the first plate solve the mount moved in RA (as it should) but the displayed angle stayed at 0° and the motion stopped then midway. To remedy this I had to first point the mount away from the pole, take a picture, sync the mount, come back to park 3 position (all with ASIAIR), before launching PA.
  2. I sent a GOTO command with the ASIAIR to M13, which was then 1h30m east of the meridian. However the mount moved in the "wrong" direction and ended up counterweight up (fortunately the scope cleared the mount - but not by much). I sent after that another GOTO command to M51 (which was about 2h west of the meridian) and this time the mount was in the standard position, i.e. counterweights down.
  3. I tried to calibrate autoguiding. The West steps were as they should (small), but when it reverted to East, the mount made a very large motion (enough to put the guide star out of the FOV). I tried then to enforce guiding speed 1x with the GTO keypad first, it worked but only to some extent (the star was lost but eventually found).
I managed to take few autoguided frames and the results are very encouraging - significantly tighter stars than with my previous mount. 

I am wondering whether there are extra steps or settings that would make the dialog between the ASIAIR and the CP4 smoother ?

Thanks for your help,

Dan
Kevin Cook
 

Hi Dan - I don't know if this will help in your situation, which is a little different than mine. I am using a Mach 1 mount with the CP3 version.  The mount is connected to my ASIAIR PRO via an RS232 cable (on the CP3 side) to the ASIAIR (regular USB connector).  When it works, it works like a charm for polar alignment, plate solving, and guiding.  Where it gets squirrely seems to be when I power up the mount first, then power up the ASIAIR - that is when the mount motions go seriously astray, sometimes starting with that first polar alignment rotation of the RA axis.  It seems as though the ASIAIR does not know when the home position (Park 3 for me) is, so all subsequent motions are out of whack. Things go much better when I power up the ASIAIR first, make sure I hear it beep that it has set up its little local wifi network, then I power up the mount and open the ASIAIR app.  No guarantees it will resolve your issues, but give my recommended startup sequence a try.

Kevin Cook

On Fri, Jun 3, 2022 at 5:28 AM Dan_Paris <danysra@...> wrote:
   Hi everyone,

since yesterday I am a happy owner of an AP900 with CP4 upgrade. What a beautiful an impressive mount! 

Coming from a Skywatcher AZ-EQ6 driven by an ASIAIR using EQMOD, I tried to use the AP900 in the same way.

I connected the ASIAIR to the CP4 with an USB cable, an turned everything on. After choosing "Astro-physics CP3/CP4" in the mount menu of the ASIAIR, the mount was instantly recognized and reacted to the arrow buttons on the phone screen. So far so good.  I then tried to simulate a full imaging session.  Everything eventually worked but there was some oddities:

  1. When I ran the polar alignement procedure, after the first plate solve the mount moved in RA (as it should) but the displayed angle stayed at 0° and the motion stopped then midway. To remedy this I had to first point the mount away from the pole, take a picture, sync the mount, come back to park 3 position (all with ASIAIR), before launching PA.
  2. I sent a GOTO command with the ASIAIR to M13, which was then 1h30m east of the meridian. However the mount moved in the "wrong" direction and ended up counterweight up (fortunately the scope cleared the mount - but not by much). I sent after that another GOTO command to M51 (which was about 2h west of the meridian) and this time the mount was in the standard position, i.e. counterweights down.
  3. I tried to calibrate autoguiding. The West steps were as they should (small), but when it reverted to East, the mount made a very large motion (enough to put the guide star out of the FOV). I tried then to enforce guiding speed 1x with the GTO keypad first, it worked but only to some extent (the star was lost but eventually found).
I managed to take few autoguided frames and the results are very encouraging - significantly tighter stars than with my previous mount. 

I am wondering whether there are extra steps or settings that would make the dialog between the ASIAIR and the CP4 smoother ?

Thanks for your help,

Dan
Dan_Paris
 

  Hi Kevin,

thanks for the tip! It solved the first problem (polar align works perfectly now), but I still have problems to calibrate autoguiding. When reversing directions the motion is far too large.

Which mount driver do you use ? So far I have only used AP CP3/CP4.

best regards,

Dan
Kevin Cook
 

Hi Dan - I used to use the ASCOM mount driver when I was running SharpCap and PhD2 guiding, but now with the ASIAIR PRO, I just select the AstroPhysics GTO CP3/4 option from the Mount Settings menu.  On the Guide Settings, after a lot of experimentation on my part and helpful suggestions from fellow TAAA astrophotographers (they are drawn to the sound of cursing in the middle of the night at our dark sky site),  I have settled on the following settings (using refractors from 420-834mm in FL, and a 50/200mm guidescope):
  • Calibration Step = 500ms
  • Max DEC Duration = 500ms
  • Max RA Duration = 500s
Those settings are much lower than I would though appropriate, but they seem to work pretty well with my setup.  I do wish ZWO would incorporate something akin to PhD2's Guiding Assistant to help dial those parameters in more precisely.  If all else fails and your system repeatedly goes nuts on Polar Alignment, GoTo, or guiding operations, try un-installing the ASIAIR app from your tablet and then re-installing the app.  That was necessary for me once, and it worked (this was another helpful suggestion from a friend who is a beta tester for ZWO.

Hope that helps.   Kevin

On Sat, Jun 11, 2022 at 7:19 AM Dan_Paris <danysra@...> wrote:
  Hi Kevin,

thanks for the tip! It solved the first problem (polar align works perfectly now), but I still have problems to calibrate autoguiding. When reversing directions the motion is far too large.

Which mount driver do you use ? So far I have only used AP CP3/CP4.

best regards,

Dan
Dean Jacobsen
 

On Sat, Jun 11, 2022 at 10:30 AM, Kevin Cook wrote:
On the Guide Settings, after a lot of experimentation on my part and helpful suggestions from fellow TAAA astrophotographers (they are drawn to the sound of cursing in the middle of the night at our dark sky site), 
That one made me chuckle.  :-)

All too often we have to suffer alone and in the dark, so you are very fortunate.
 
--
Dean Jacobsen
Astrobin Image Gallery - https://www.astrobin.com/users/deanjacobsen/

Dan_Paris
 

Thanks Kevin for the tips.


I found a trick to get successful guiding calibration. I first set guide rate to 0.5x with the keypad, then calibrate with the ASIAIR, set back the guide rate to 1x and calibrate again. A bit convoluted bit it works!
Brian Valente
 

Nice work Dan

I have no idea how you figured out that workaround :)

On Wed, Jun 15, 2022 at 4:19 AM Dan_Paris <danysra@...> wrote:
Thanks Kevin for the tips.


I found a trick to get successful guiding calibration. I first set guide rate to 0.5x with the keypad, then calibrate with the ASIAIR, set back the guide rate to 1x and calibrate again. A bit convoluted bit it works!



--

Kevin Cook
 

Dan - I used to do something like that when I first started using the ASIAIR, as I would start up with the AP keypad connected (thought it was necessary to have info on mount location and local time).  However, I have not connected the keypad for nearly a year now, and things actually seem to go more smoothly.  I guessing that the ASIAIR program is picking up the location and time info from the mount's last setting, or from the tablet, or possibly from the polar alignment process.  In any case, I no longer use the keypad (though I still always bring along as my security bblanke), and the ASIAIR aligns and executes GOTOs properly.  However, the normal guiding parameters that I would use from back in the PhD2 days did not seem to calibrate well with the ASIAIR.  That is what led me to experiment and start using much lower numbers for the calibration step size and max DEC and RA durations.  There is a tracking rate slider at the bottom of the GOTO panel in ASIAIR, but I eventually concluded that only affects the rate for the directional buttons on the GOTO panel and did not really seem to affect the guiding rate.  

This site has a good discussion of setting guiding parameters for the ASIAIR (though as I mentioned previously, I have deviated in a big way from their recommendations):


Kevin

On Wed, Jun 15, 2022 at 4:19 AM Dan_Paris <danysra@...> wrote:
Thanks Kevin for the tips.


I found a trick to get successful guiding calibration. I first set guide rate to 0.5x with the keypad, then calibrate with the ASIAIR, set back the guide rate to 1x and calibrate again. A bit convoluted bit it works!

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