Plate Solving woes...

[astromusic]

Hi Robin,

For some reason, I cannot get Plate Solving to work within SharpCap. I have All Sky Plate Solver installed, and have installed almost all of the resolution libraries. The only parameter available seems to be the Sigma parameter, which you have to set blindly; I have tried 1,2,5,10.

If I do a FITS capture from SharpCap, and directly feed the file to All Sky PS, it always seems to solve it within 1 minute, so I know it is installed properly. SharpCap doesn't give any error messages, just tries very hard for a long time, with no results. Once, just once out of many attempts, it did actually solve it, and gave me the right results (that time I had 10 second captures, with sigma of 1, but I can't repro the result with the same settings). A couple of screenshots attached to show the problem. In both cases, I let SharpCap go for a while, then took a capture, and fed it to ASPS, and got the results back while SC was still struggling.

Another fact: ASPS was not able to solve the plate as well, until I entered the Focal Length correctly. I can't find a place in SharpCap to enter Focal Length; am I missing it somehow?

One more fact: Plate Solving works like a charm for Polar Alignment, but of course that uses your internal engine.

Telescope - Orion ED80, with Focal Reducer, effective FL 400mm. Camera: ASI385MC.

(Edited to attach Log file from one of the attempts)

Also, after poring through the logs, I have some questions:

1. Looks like the mount connects properly; however, it seems to be doing a "blind plate solve". I don't see anything in the log that says it read the RA/DEC from the mount. Could this be a problem?

2. The ASPS seems to default to a binning of 2. Maybe that's why it converges faster with its blind plate solve?

Thanks,
-Kal.

PlateSolveSwan.PNG (833.37 KiB) Viewed 1840 times

PlateSolving.jpg (204.42 KiB) Viewed 1840 times

[admin]

Hi,

SharpCap has two types of plate solving. The one you seem to be using is the blind plate solve from the menu – this will attempt to perform a full plate solve over the whole sky without any clues being given to the plate solving engine about focal length or location. This takes a long time on occasion and tends to work best when the number of detected stars is between 50 and 100.

The second type of plate solving is launched from the telescope controls in the right-hand panel by clicking the GPS location button. This plate solves by giving the engine a hint based on the current coordinates and asking it only to solve within 15° of that location. It still doesn't need to give the engine hint about field of view, but tends to be a lot faster because it only needs to consider a smaller area of the sky.

If you look in your logs you should see the number of stars being detected by the plate solving engine in one of the lines of the log file. If the number of stars is lower than about 50 then decrease the sigma value which should increase the number of stars. If the number of stars is much more than 100 then increase the sigma value.

Hope this helps, Robin

[astromusic]

Ah, I wasn’t aware of the two types. The Telescope control panel was not visible on my small screen, so I didn’t know it was there. That seems to work fine and solves fairly quickly.

As for the sigma setting hint, the log has a line like “simplexy: found 85 sources”. Is that the number of stars detected?

[admin]

Hi,

Yes, that's the number of stars found. 85 is good number for this.

Cheers, Robin