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Observing Variables is where I make most use of my binoculars. Many Variable Stars are within the grasp of a good pair. I use 10x50's, but any size will do the job. It's only when the star fades to below +7 that a scope is needed. As a Double-Star observer, Variable Stars and Double Stars are related in that there are a couple of classes of Variables that are also compsoed of Binary Stars. The Variable class of Eclipsing Binaries is a system of two stars that cannot be visually split into their individual components because the orbit of the stars is aligned edge-on to our line-of sight. My Variable Star Observing program contains two of these stars; the famous Algol (Beta Persei) and RZ Cassiopeia.
Of all the types of variable stars to observe, the LPV's tend to get ny vote as they show the greatest visual magnitude swing and can be very rewarding as they can reach naked-eye brightness and then dim to the point where only by using a modest telescope can the observer record the magnitude of the star. For the amateur, observing variables can be great fun as you only need your eyes as with the well-known Eclipsing Binary Beta Persei (Algol) high in the sky during autumn and winter nights.
Below is Chi Cygni (center crimson star) at visual magnitude +12.3,estimated by myself.
Imaged with a CCD camera in August 2009 by and reproduced with kind permission of Brian Joynes.
Other Variables that I'm keeping tabs on are the Long Period Variables (LPV's), Chi Cygni, Omicron Ceti (Mira) and T Cephei. The LPV; X Camelopardalis is a new addition to my portfolio. This star presents an exciting challange as its period is 143 days, varying in magnitude range 8.1 - 12.6! The later two are circumpolar from my lattitude and so can be observed all year. There are also two Cephids that I am also aiming to follow. Delta Cephei and Eta Aquila.
Updated 14/11/2009
All images are Copyright © 1999-2009 John Cox
