A quick pointer on SG PS2 please


Hi, I’m aware this issue has been discussed many times but can’t crack it…

PS2 solving using an Atik 460EX (~30x24 arcmin field @ 1.2 arcsec/pxl 2x2 binned).
Perfect, instant results every time.

PS2 using an OrionG3 (13x10 @ 1.093 a/p 1x1).
Failure every time.

The frames do (eventually) solve in All Sky Plate Solver and AstroTortilla (hence the accurate plate size and scale) but the wait time kills the object of the automation.

I don’t fully understand what the PS2 “Parameter” values actually do. Are they explained anywhere?
Any perceived difference in performance between APM and UCAC3?




I don’t recall discussing this a bunch. I might remember one case where this was true, but since we don’t have this camera we might not have been able to determine if it was hardware or settings.

Do you have this frame you can send up to dropbox to share?

We try to hide these from users as they are not super intuitive, but you asked…

Short Story: Scale, Ra, Dec via SGPro. That’s it.

Long Story: What SGPro does behind the scenes…

  • Convert RA to degrees, then radians (to 14 decimals)
  • Convert Dec to radians (to 14 decimals)
  • Convert the image width in pixels to radians using image scale (to 14 decimals)
  • Convert the image height in pixels to radians using image scale (to 14 decimals)
  • Define the number of catalog regions to search before failure
  • Point PS2 to the FITS file location

This is also the order of the params as passed to PS2.

None that I’ve noticed. Others may have more color to add here.


Many thanks.
Three un-calibrated files as downloaded straight from the camera for different fields/stars. All failed in PS2…

AW Gen

IR Gem

V405 Aur





Those links all seem to be private.


Apologies Ken I’ve opened up the Dropbox folder.