Measurement Tool

This is another good useful resource (found in the ArXiv listing today.) 

What would be very useful is a measurement tool giving separation in arcsec and position angle in degrees, whose accuracy would be in the order of 0.01 arcsec and 0.01 degrees. This could be used to estimate distances or sizes of unknown objects or stars between any two points, and would be useful in some double star work when looking at GAIA data for distant companion stars. This tool is similar to that already available in CDS Aladin, tweaking only the precision displayed.