Variable Stars

Following the mid-month meeting on 10th Nov here are some resources and suggestions for variable star observing:


The American variable star organisation and their beginners programme.


 The SPA site and beginners programme.


Calculator to forecast minima times for Algol (when it is in eclipse)

 Article by Gary Poyner.

 BAA variable star section, click on beginners on sidebar to go to beginners observing programme.


 To get started it was suggested that the following would make suitable targets, observing with naked eye or with binoculars (10×50)

Eclipsing Binaries:

Beta Persei (Algol), nightly observations but hourly either side of predicted minima ( see calculator)

Beta Lyrae, nightly observations, early evening , while still relatively high.

Pulsating Super Giants:

Delta Cephei, nightly observations.

Zeta Geminorum, nightly observations.

For all four targets see the SPA link ( 4th link-observing programme) for further notes and star charts with comparison stars, if you were at meeting you also have alternative star charts /comparison stars that were circulated.

Recording observations:

Date Day time Estimated brightness Estimated magnitude Conditions
07/03/10 1 22:30 Equal to epsilon and zeta perseus.

Dimmer than alpha perseus.

3.0 No moon, cold with low humidity, some high haze.
15/03/10 9 21:10 Brighter than epsilon and zeta perseus, but dimmer than alpha perseus. 2.2 Cold, no moon, high hazy cloud.
23/03/10 17 21:30 Brighter than epsilon and zeta perseus, but dimmer than alpha perseus. 2.2 Cool, light haze, moon first quarter, but 20Oto S.



Record in a similar format as above, compare variable to other stars on charts to get estimate of magnitude, remember lower the number the brighter it is.

Once you have collected enough data , have a go at plotting light curve, magnitude on vertical axis,with magnitude decreasing down the side , time on horizontal axis.

For Algol convert time from first observation  into hours, for the others days is fine.

Any queries come back to me,


Pete Hill




1 Response

  1. Thanks Peter. I found the second link (the pdf one) very helpful. I discovered last night that you don’t need a scope or binoculars to make the observations. (I missed the talk the other week.) Can you recommend a variable star chart, and where to get it from? Some of them are very expensive, and I don’t want to spend massive amount.

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