View Full Version : Occultation of Stars

29th June 2007, 10:32 AM
Hi to all!Can any of my friends plz tell me,what exactly is the'occultation' of a star? I saw a video clipping named "Occultation of Iota Cancri".It was wonderful to see it. To be honest,I did n't quite understand what was going on.I know this much that the 'Iota Cancri' is a huge double star of the Cancer constellation.I am told that 'Cancer' is rather pale than two of its neighbouring constellations-Gemini & Leo.Is it because of the fact that "Cancer" contains less bright stars?I mean,is this the only reason for it being pale?

Professor Yaffle
29th June 2007, 10:38 AM

An occultation is an event that occurs when one object is hidden by another object that passes between it and the observer. The word is used in astronomy (http://en.wikipedia.org/wiki/Astronomy) (see below) and can also be used in a general (non-astronomical) sense to describe when an object in the foreground occults (http://en.wikipedia.org/wiki/Occult) (covers up) objects in the background.

http://www.floridastars.org/IOTACAN/iotacancri.pdf - about the specific event you are talking about.

29th June 2007, 10:39 AM
Occultation: Occurs when a celestial body seems to disappear because another body passes between it and the observer. A solar eclipse is an occultation of the Sun by the Moon.


Don't be afraid of Google. Hope this helps.

29th June 2007, 10:59 AM
In answer to the second part of the question, yes Cancer just contains fewer bright stars than its neighbours.

29th June 2007, 11:01 AM
In answer to the second part of the question, yes Cancer just contains fewer bright stars than its neighbours.

The Cancer is eating the healthy ones...

29th June 2007, 11:03 AM
And here I thought was another thread about Tom Cruise ;)

29th June 2007, 11:32 AM
I think something important got forgotten here.

Occultations are mostly caused by asteroids passing between us and stars. The reason most instances of this type of occultation occur in stars in constellations in the ecliptic is because the constellations in the ecliptic are in the plane of the Solar System. Asteroids don't just go around the Sun any old whichway, they orbit in the same plane as the planets (mostly). For most of the larger, better-known asteroids, like Ceres, or Eros, the times of occultation are known quite a ways in advance, and some amateur astronomers like to watch them happen.

An interesting thing about occultations is that they often, like Solar eclipses, aren't visible from everywhere on Earth. So you'll get a "path" over which the occultation will be seen, but outside that path, you won't see it.

29th June 2007, 12:35 PM
Thank you,all my friends for the nice replies.Have a really nice time.