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Mika Luostarinen - Variable Star Observing
History | Gallery | Instruments
Astronomy has been my hobby for more than 30 years. I have observed practically all objects available on the sky: deep-sky objects (galaxies, nebulas, star clusters), planets, double stars, variable stars, asteroids, sun, moon, comets etc.
These days - since 1999 - I have been focusing solely on variable stars. These enigmatic objects have been keeping me busy the last 9 years and observing them is great fun !
 Cataclysmic variable |
 Cygnus X-1 |
 Accretion disk
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But what are they ?
Not all stars are static points of light. Variable stars change their brightness over a period of time. Some variables go thru physical changes. In these processes they may destroy themselves by exploding or they may just blow their outer layers away. Some stars - namely the cataclysmic variables - like to pull in some extra material from their companion star.
Cataclysmic variable stars (and dwarf novae in particular) are complex stellar systems and there are still many things we do not currently understand that well. Further observing is thus needed.
Some variables change their size and even color periodically. These pulsating variables are interesting and fun to observe. Some of these stars are giants or supergiants. These stars have complex internal convection processes while they change.
Not all variables change physically. Eclipsing binaries are systems where two stars orbit closely each other. The dimmer star periodically moves in front of the brighter star causing a dip in the lightcurve. Eclipsing binaries are handy. Among other things these stars have been used to deduce the distance to globular clusters and nearby galaxies.
At the moment more than 30,000 variable stars are cataloged and many more are suspected to be variable. Many amateurs have found new variable stars.
What amateurs can do?
By observing variable stars we collect important information how the stars change and evolve. Major part of the current knowledge of stellar structure and evolution is based on variable stars and their behavior. Scientific theories about stellar evolution is often based or verified using the observations made of these stars.
Today, there are more than 10 million observations in the AAVSO international database of variable stars. These observations are made by dedicated amateurs and the database is regularly used by the professional astronomical community.
All space art in these pages is copyrighted © by Mark A. Garlick (with permission)