Estimating Magnitudes

With a little effort, you'll eventually find a variable star. When you've found one, you probably should estimate its brightness since this is at the heart of variable-star observing. Your accurate estimate is going to be important and you must take the time to do it properly. Initially, accurate magnitude estimates may require a little time to prepare. As you gain experience, estimates can be made rather quickly in most cases.

First, examine your star chart carefully. While using your binoculars or while at the telescope, identify the variable star and verify the relative brightness of all comparison stars. The first few times that you do this will require a little bit of time. After five or ten minutes you may start wondering if you're doing something wrong or if there is something that you don't understand. Don't be too concerned; this is common. Keeping track of your variable star and finding the comparison stars can be tricky at first. It won't be long before you begin to recognize the different star fields.

To estimate the magnitude of a variable star you simply determine which comparison stars are closest in brightness to the variable. Unless the variable is exactly the same brightness as one of the comparison stars, you will have to interpolate between a star that is brighter and a star that is fainter than the variable itself. This sounds simple and it is, but it takes practice to be skillful. Practice takes time and effort and all of this can only be done at night. These are reasons why you're the only variable-star observer in your neighborhood.

Your first few magnitude estimates need not be shared with anyone. Keep them a secret so you can side-step the pressure of making a near perfect estimate. Eventually, with a little practice, you'll develop more confidence in your estimates and then you'll feel good about reporting them. Let's take a look at how we actually make an estimate.

0 0

Post a comment