document.title="Catch a star - variable stars"

" From the dawn of time, stars have fascinated humans.
Because of this, tremendous amounts of brain power and money have been invested in the exploration of this fascinating unknown around us.
- The aim of this group is to investigate one of the most interesting type of stars, the variable star.

Lambda Cygni

Stars in the sky appear to be shining with a constant light, but thousands of stars vary in brightness. The apparent magnitude of a star depends on its distance from Earth and its absolute magnitude. The behaviour of stars that vary in magnitude can be studied by measuring their changes in brightness over some time and plotting the measured changes on a graph. Provided that our measurements are correct, we will now be able to determine whether the star is variable or not.
The behaviour of some variable stars can be observed with the unaided eye or binoculars. Measuring and recording the changes in apparent magnitude and drawing the resulting light curves will allow us to begin unravelling the history of the variable stars of our choice. The collection and study of variable star data requires the ability to estimate the apparent magnitudes of stars. The two activities that follow will assist you in acquiring the skill of estimating the magnitudes of variable stars.


Varable stars are mostly common Astronomers have known of stars that undergo substantial changes in size, alternately swelling and shrinking. As these stars pulsate they also vary dramatically in brightness. It is the alteration in brightness of the star Lambda Cygni that we will try to confirm.
In our measurement we have taken pictures of the variable star Lambda Cygni in a part of its period. By counting pixels in these photos we will try to estimate the size of the magnitude. Being able to do that implies that we have one or more reference stars in the same picture. The reason we have to include reference stars is to avoid potential sources of error such as mist.