Re: APPM model how many points portable?

Greg Vaughn

Hi Roger,


I started off with platesolve2 and SGP to support APPM and found it VERY SLOW.   When I switched to ASTAP as my plate solver in SGP, it sped things up tremendously.  Yes you can use ASTAP in SGP in conjunction with APPM.


I had some difficulties recently with APPM that turned out to have nothing to do with the software.   When I used APPM on a larger/longer refractor my 12V power cable on the back of the CMOS cooled camera was catching on something when it got to a certain geometry in the mapping sequence and then the camera failed to take an image because the 12V power was interrupted (12V power is no longer used just for cooling on some of the newer CMOS cameras) – I just couldn’t understand what was happening, 35-45 good solves (I tried varying the number of points in the mapping, thinking that would help) and then it hung.   The break was only at a certain cable angle and then the power would return when it was back in the APPM starting position.  I was in the kitchen working remotely and I couldn’t see the problem that reappeared four times.)  It took another night of troubleshooting a couple weeks later to figure the power problem out.  In the meantime I followed the suggestions from forum participants for my full frame, high MP camera of doing only a ‘½ by ½ center’ frame capture to speed the download – this is selectable in APPM under ‘camera setting’ – which would make sure my downloads weren’t falling behind and creating a problem.  I was already doing Bin 2 platesolves which also seemed to speed the process.  (The other recommendation, which I followed, was to download the 64 bit Beta version of SGP.)  My last two times out with my primary optical train and this configuration (and a new 12V power cable), everything went very quickly and successfully.


I don’t know your setup, but you may be interested to know that when I first started with APPM, I was using a Nikon DSLR with SGP.   The instructions from Ray are to set the recording in SGP from the DSLR to FITS images.  My initial attempts to try ‘FITS + RAW’ (thinking that was even better) were unsuccessful.  Choosing ‘FITS’ as instructed  was the cure.


A final lesson learned.  I went back to my Nikon DSLR to try a different image train and mount last weekend.   I had difficulties with SGP (64bit) downloading images from the Nikon – even though it showed being properly connected and powered on.  In fact I could download JPEG images for the frame and focus module, but couldn’t download or record any FITS files during an otherwise smoothly running SGP sequence or for APPM.  I received an error from SGP that it couldn’t download the frames and a dialog box saying that some files could not be found and might be restored if I re-installed the software.   I incorrectly thought the reinstallation recommendation was for SGP and I reloaded it without any effect and before giving up.   It turned out to be the ASCOM platform that had the files and needed to be reloaded.   So I went ahead and updated from 6.4 to 6.5SP1 and everything worked well after that (although at that point I was troubleshooting in my basement the following day!).  I setup and ran through a sequence (without guiding) and it worked fine and downloaded images without protest.


In general, to get things off to a good start and make sure I have all the right settings, I do the following (regardless of which camera or AP mount):


-Focus routine in SGP with Lum filter (or OSC/DSLR)

-Run a ‘Solve and Sync’ in SGP with Lum filter (or OSC/DSLR) to confirm all is well on the SGP end (platesolves using Bin2)

-Open APPM, show points, connect ‘scope’ and ‘camera’ (through SGP)

-Run about a 68-85 point model to cover the partial sky that I can image in (2-3 points per minute, depending on mount and slew speed)

-Accept the model and disconnect the ‘scope’ and ‘camera’ (SGP) from APPM

-Start my sequence


This results in excellent pointing and good guiding.  (Guiding improves even more with a good polar alignment.)


Hope this helps.  One amateur’s approach.


Cheers and clear skies.




p.s. I know you asked about how many points for a portable setup – I didn’t answer that and I am interested in that answer as well because right now I have the luxury of 120VAC and will want to use APPM at dark sites as well and not unnecessarily deplete my battery. 


Greg Vaughn

Alexandria, VA



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