For Castor "magnify" centers the star and zooms to a 26 by 13 degree field of view (screen1). Doing the same for Pollux results in zooming in to <1 second by <1 second but on the way Pollux disappears off screen and a new Pollux appears in a slightly different position along with its binary(screen 2). Centering on Sirius zooms out slightly, centers Sirius, then zooms in again to <1 second by 1 second (screen 3). From there, "magnify" on Sirius zooms out to 100 by 53 degrees (screen 4). Can anyone explain this strange behaviour?