If I type in a target in the sequence and click ‘Center Now,’ it runs and runs and plate solving fails (but this method works fine with my SV70t APO). If I take a quick 15 second frame or so manually, then plate solve, it works and can solve.
Any ideas? I’m fairly new to SGP and imaging all up, I’m sure I’m overlooking something in my config.
Going from the SV70 to the 8" is a pretty big jump in focal length and change in image scale. It may be failing due to the pixel error( default is 50) and or number of tries before it fails out. Try setting the pixel error in the plate solve module to something high like 200 0r 300, and set the number of tries higher…maybe 10. This assumes your scale is correct…check your FIT’s header, the actual scale will be there. If it solves, then you can start decreasing the pixel error down again to find what works best to center the target as close to center as you can get. With my camera and due to limitations of the driver for my scope I have to use a pixel error about 550. This still puts the image a 1/4 of the way from center in my image…have to manually frame the rest of the way, but it’s ok.
John
I sometimes image with my 8" Tal 200K and your pixel scale is paramount to getting good platesolving. I platesolve consistantly using the default settings and the target is always dead centre.
I use Ron Wodaski’s CCD Calculator. As the ASI 1600M is a recent cmos camera, you may have to input you your chip size & pixel details in the calculator. http://www.newastro.com/book_new/camera_app.html
15 seconds shot is quite long for plate solving. I found that platesolve2 fails if there are too many stars in the shot. I use 4 seconds if I remember correctly.
You can also take a photo and upload it to Astrometry.net and plate solve it there. When it is done solving, click on the blue link text that says “go to results page”. On the right side it will tell you about your image scale and rotation angle. For example I just did it on an image I had and it reported:
Calibration
Center (RA, Dec): (43.715, 60.399)
Center (RA, hms): 02h 54m 51.538s
Center (Dec, dms): +60° 23’ 55.187"
Size: 2.19 x 1.75 deg
Radius: 1.399 deg
Pixel scale: 1.74 arcsec/pixel
Orientation: Up is -178 degrees E of N
Then take the information and plug it into SGP. Bin 2x2, use a clear filter, and expose for 10 seconds.
Speaking of which, you can also set up the blind fail over using the offline version of astrometry.net