Welcome to Astronomy & Telescope Astronomy



· Home
· AvantGo
· Content
· Downloads
· Encyclopedia
· Feedback
· Forums
· Journal
· Members List
· Private Messages
· Recommend Us
· Reviews
· Search
· Statistics
· Stories Archive
· Submit News
· Surveys
· Top 10
· Topics
· Web Links
· Your Account

  Who's Online

There are currently, 12 guest(s) and 0 member(s) that are online.

You are Anonymous user. You can register for free by clicking here




Select Interface Language:


  Random Headlines

[ Meteor ]

·Astronomy: Meteor - Speed-SPEEDY METEORS
·Astronomy: Meteor - Space Rock-ROCKS FROM SPACE
·Astronomy: Meteor - Observing Meteor-WHEN TO OBSERVE
·Astronomy: Meteor - METEOR STREAMS
·Astronomy: Meteor - Meteor Storm-SPORADICS, SHOWERS, AND STORMS
·Astronomy: Meteor - Meteor Shower-PREPARING FOR A METEOR SHOWER
·Astronomy: Meteor - Meteor Log
·Astronomy: Meteor - Leonid Meteor-THE LEONID METEOR STORM
·Astronomy: Meteor - HOW MANY METEORS

  Variable Star: Astronomy: Variable Star - Magnitude-HOW BRIGHT
Posted on Saturday, December 11 @ 01:27:24 CST by astronomy
  Variable Star


After locating a variable star, many observers estimate its apparent magnitude. There are various methods, but most use an interpolative method, comparing a variable's brightness with that of nearby stars.

The American Association of Variable Star Observers (AAVSO) provides finder charts for individual variables that show the magnitudes of surrounding stars. Say the variable is not as bright as comparison star A, but is brighter than comparison star B. From your AAVSO chart, you know that star A is magnitude 8.5 and star B is 9.0, so you might estimate the variable's magnitude as 8.7.

The British Astronomical Society's method also uses comparison stars, but you do not need to know the magnitudes of the comparison stars until after the observing session.

Observing a star that is too bright for your telescope may result in an inaccurate magnitude estimate. A 4 inch (100 mm) telescope should not be used on stars brighter than 7th magnitude. The limit for 6 to 8 inch (150 to 200 mm) telescopes is magnitude 8.5. You can cut down the aperture of your telescope by making an aperture mask.

Some observers photograph variable stars. This provides a permanent record and allows them to estimate the magnitude away from the telescope.

For precise measurements of a variable's brightness, amateurs can use a photoelectric photometer, a device that attaches to the telescope's focus. CCD technology can also be used for photometry.

Groups such as the AAVSO or the Variable Star Section ot the British Astronomical Association welcome visual, photographic, and photometric observations from amateurs, and can provide further advice about variable-star observing.




Don't have an account yet? You can create one. As a registered user you have some advantages like theme manager, comments configuration and post comments with your name.

  Related Links

· More about Variable Star
· News by astronomy

Most read story about Variable Star:
Astronomy: Variable Star - CLASSES OF VARIABLES


  Article Rating

Average Score: 0
Votes: 0

Please take a second and vote for this article:

Very Good



 Printer Friendly Printer Friendly

 Send to a Friend Send to a Friend


Associated Topics

Variable Star

"Login" | Login/Create an Account | 0 comments
The comments are owned by the poster. We aren't responsible for their content.

No Comments Allowed for Anonymous, please register

  Astronomy & Telescope Astronomy

All logos and trademarks in this site are property of their respective owner. The comments are property of their posters, all the rest © 2004 by Astronomy & Telescope Astronomy
You can syndicate our news using the file backend.php or ultramode.txt