Welcome to Astronomy & Telescope Astronomy

 
 

  Modules

· Home
· AvantGo
· Content
· Downloads
· Encyclopedia
· FAQ
· 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, 8 guest(s) and 0 member(s) that are online.

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

  Search



 

  Languages

Select Interface Language:

 

  Random Headlines


Telescope Type
[ Telescope Type ]

·Astronomy: Telescope Type - Telescope for Children-BUYING FOR A CHILD
·Astronomy: Telescope Type - SCOPE SPEED
·Astronomy: Telescope Type - LENS OR MIRROR
·Astronomy: Telescope Type - Image-WHICH WAY UP
·Astronomy: Telescope Type - HYBRID SCOPES
·Astronomy: Telescope Type - BUILDING YOUR OWN
·Astronomy: Telescope Type - APERTURE NOT POWER
·Astronomy: Telescope Type - ALVAN CLARK AND SONS
·Astronomy: Telescope Type -
 

 
  Sunlit Cloud: Astronomy: Sunlit Cloud - Halo-SUN COMPANIONS
Posted on Friday, December 10 @ 19:00:19 CST by astronomy
 
 
  Sunlit Cloud

SUN COMPANIONS

Another common sight in daytime skies is the halo, sometimes called "a ring around the Sun." Haloes are caused by the refraction of sunlight through hexagonal ice crystals in cirrus clouds.

As the sunlight passes through one of the six sides of the tumbling crystal, it is bent through a 22 degree angle, producing a halo with a radius of 22 degrees. Occasionally, when sunlight passes through the ends of hexagonal prisms, or through cubic ice crystals, it is bent through a greater angle, producing a second, fainter, 46 degree halo.

When the Sun is low in the sky, and when high cirrus clouds are present, look for two bright spots of sunlight on either side of the Sun. These spots, which will be tinged red on the inside and blue on the outside, are commonly called sun dogs or mock suns. The technical name is parhelia.

Sun dogs are produced by sunlight refracting through hexagonal ice crystals that are oriented with their bases parallel to the horizon. Sun dogs sometimes touch the outside edge of a 22 degree halo.

The safest way to observe sun dogs and haloes is to block your view of the Sun with a nearby structure such as a tree limb, chimney, or flagpole.
Yet another ice-related phenomenon, sun pillars, can he seen around sunrise or sunset. When low-angle sunlight reflects office crystals in cirrus clouds, a spike—or pillar—of light may be projected up from the just-set or predawn Sun.

At night, moonlight can create moon haloes, moon dogs or mock moons, and moon pillars, but these effects fainter and less common than the Sun phenomena.

 
 
  Login

Nickname

Password

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 Sunlit Cloud
· News by astronomy


Most read story about Sunlit Cloud:
Astronomy: Sunlit Cloud - Rainbow-OVER THE RAINBOW

 

  Article Rating

Average Score: 0
Votes: 0

Please take a second and vote for this article:

Excellent
Very Good
Good
Regular
Bad

 

  Options


 Printer Friendly Printer Friendly

 Send to a Friend Send to a Friend

 

 
 
Associated Topics

Sunlit Cloud
 
 


 
 
"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