Variable of the Month
V818 Sco

This star is also known as Scorpius X-1  (Not XI Scorpii, that is another story, as 
Kipling used to say)  V818 Sco is the most powerful Xray emitter in the sky and
was the first discrete Xray source to be discovered.  Burnham devotes nearly three 
pages to this fascinating object and interested readers are advised to read his article.

The star is an eclipsing binary with an amplitude of about 0.2 magnitude and a 
period of .787 days.  Superimposed on this is distinct flickering so the star always 
surprises the observer. I have made more than a thousand observations of it but it 
can certainly do with many more visual and CCD observations. Its visual range is 
nearly a magnitude.

Amateurs who like to see things happening will do well to add it to their repertoires.  
Please contact me if you are not sure about identifying it.

Danie Overbeek.
danieo@global.co.za

Sky Map