Hi,

I recently discussed with a colleague about 61 Cyg the hi prop motion star: http://en.wikipedia.org/wiki/61_Cygni

I tried to simulate the path of the star across the sky from 2008 onwards and found that there is something really wrong.

The problem can be seen most easily if you have a look at the animated gif picture here at the top:
http://www.solstation.com/stars/61cygni2.htm

61 Cyg AB obviously move perpendicular (!) to the line connecting the two components A-B. However in Guide 8.0 I see the two components moving roughly (within 20° or so) along the line A-B... The orbit of A + B around each other is NOT fast enough (678yrs orbital period) to change the PA so much.

Something's definitely wrong, it seems: either the A + B positions (at roughly 30" distance) or the proper motion vector in Guide 8.0 or both...? Or did I miss some data updates I should have downloaded ?

Thanks for any help + comments,
Peter