M27 – Dumbbell Nebula
July 22, 2017 – 300 seconds on T3
WDS ROE 10 – Double Star in Vulpecula
July 22, 2017 – same frame as M27
A = [19 58 47.43, 22 28 52.8] B = [19 58 47.07, 22 28 44.9]
This gives separation of 9.3 arc seconds, which matches the WDS well, and position angle of 32 degrees, which differs from WDS PA of 67 degrees. This separation is at the outer edge of T3 and Astrometrica’s ability to distinguish.
Paul's Notebook 