A Few Observing Tips

The best tactic is to familiarize yourself with these stars and get in the habit of routinely checking up on them every clear night. Be prepared to maintain this vigil for many months to come. You might well be the first person to discover what makes one of these "unsolved variables" tick.

The techniques for making visual magnitude estimates are not very demanding. (For more detailed information, see "The Lure of Variable Stars.") Since the stars on our list are 7th to 9th magnitude, they can all be seen in a good pair of binoculars. But if a star is within a couple of magnitudes of the limit for a particular instrument, it can be seen clearly only by "averted vision" — directing your gaze a little to one side.

It's easier to compare star brightnesses when you can look right at them. A 3½-inch or larger telescope should guarantee this for the stars on our list, but don't use too large a scope or the field of view will be too narrow. For reliable estimates the variable and comparison stars should appear in the same field and well in from the edges.

Try to select comparison stars that bracket the variable star in brightness, differ from it by less than 0.5 magnitude, and have a similar color. The colors on our charts are an excellent guide for they, like the magnitudes of the comparison stars, are derived from Tycho photometry of the Hipparcos mission. The colors are more vivid than those you will see at night. By convention, comparison-star magnitudes are indicated to tenths with the decimal point omitted. Thus, a star labeled "79" is magnitude 7.9 visually.