A question on which coordinates to use. Tonight I wanted to try the Elephant’s Trunk nebula (IC1396), but the plate solver seemed to be having difficult time finding a match after slewing. I wanted to check the coordinates, and got the following:
Telescope (CEM40): RA=21h39m34.3s, Dec=57d34m35s
Stellarium: RA=21h39m00.01s, Dec=57d29m24.0s
SkySafari: RA=21h39m41.49s, Dec=57d35m11.2s
Telescopious: RA=21d39m05s, Dec=57d30m00s
That’s a range of 41 seconds in RA and 5 minutes in declination. Not terrible, but I’m curious why there seems to be no consistency between the results. More importantly, if I want to center a target and my FOV is relatively small, an accurate coordinate seems to be necessary. Any idea which one I should use?
I did use the observing list from Telescopious a couple of days ago, but SGP now says that it’s an invalid URL so I have to put the coords in by hand, so knowing which app has the closest coordinates is important.