Finder Charts

Finder Charts

Recommended Variable Stars for Canadian Observers

How To Use The Charts

Variable-star charts are specially prepared charts that display the magnitudes of nearby stars known to be stable in the sense that they do not vary in brightness to any noticeable degree. Variable-star charts come in a variety of scales that are not necessarily designed to help you initially find the variable star that you are looking for, except in the case of the large field AAVSO Variable Star Atlas; an optional item. In fact, any large-scale atlas like SkyAtlas 2000, Uranometria, or others are just fine for tracking down relatively bright well-known variable stars. Once you find the variable star you are looking for, then you will have to determine which chart is the most appropriate to use based on the current magnitude of the star.

Chart Magnitudes and Scales

For variables that do not change to a great degree, one chart is usually sufficient to provide enough comparison stars to accurately estimate the brightness of the star throughout its entire cycle of variation. For other stars like Long-Period Variables, the range of variation is great enough that two or more charts are needed to measure the star at different times during its cycle. In other words, when a variable star is near maximum, you will need brighter comparison stars and possibly a larger chart field to estimate the magnitude; when it is near minimum, you will need fainter comparison stars and possibly a smaller chart field to estimate the magnitude. Some variables have as many as four or more charts available to follow their entire cycle accurately.

Choosing Stars to Observe

Most of the stars that were chosen for this sample list are known to be suitable for new or casual observers, and we have included links to more than one chart per star if that star requires them. The charts can be printed by simply clicking the print button in your browser, or you can download the charts and open them in any basic graphics or paint program included with most standard operating systems. The charts might print better when downloaded and opened in a graphics program, but we have had good results printing right from the browser.

Sending in your Observations

We encourage you to send in your variable star estimates to the AAVSO since they will accept observations from members and non-members alike. Details of the various methods to submit observations can be found on our Observing Forms page and at the AAVSO Web site.

Last modified: 
Tuesday, April 17, 2012 - 10:05pm