Hello Observers,
I was out last night observing eclipses of 4 stars. One is one of my all time favorites, and nicely placed for late summer/autumn. CX Aqr is an Algol type eclipsing binary (EA) with a period of 0.5559862 days. It's magnitude range is 10.6-11.8 visual. I love it for 2 reasons.
1. If you print off a "c" chart from the VSP, you will notice the very bright star on it. This is Eta Aqr. CX is just a very short star hop away, following an easy star pattern.
2. This star starts off somewhat slowly, then turns on the speed. Within a 10 minute period (how often you should make an observation), it can drop .2 to .4 magnitude. When it hits bottom, she comes right back up, but at a quicker speed. I always find the ascending branch of the light curve to be a bit more steep than the descending.
Print off a chart and give this one a try. You can get the predicted times of minima from the AAVSO website. Just do a search for Eclipsing Binary Star Ephemerides for 2013.
Good Observing!
Chris Stephan SET
Burton, OH
I was unfamiliar
Hi Chris,
I was unfamiliar with CX Aqr and your message prompted me to look up a lightcurve. See:
http://caleb.eastern.edu/large_lc_display.php?model_id=446
The ascending and descending branches are mirror images of each other until the star is very close to its out of eclipse brightness.
Cheers,
Doug
Yes, this one is easy to find, right on the equator so good for both N or S observers, has a substantial range for visual, and exhibits rapid change during the eclipse too. Excellent for introducing VSO to people at star parties for example!
I could suggest adding another comp star to cover the relatively wide 103-110 range for better estimation. Good choices might be TYC 5233-1997-1 V=10.80 B-V=+0.59 or TYC 5233-1819-1 V=10.72 B-v=+0.60
Mike LMK