Astronomy Picture of the Day 4-21-03

NASA ^ | 4-21-03 | Robert Nemiroff and Jerry Bonnell

[petuniasevan]

Astronomy Picture of the Day

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2003 April 21 A Halo Around the Moon Credit & Copyright: Sarah McKay

Explanation: Have you ever seen a halo around the Moon? This fairly common sight occurs when high thin clouds containing millions of tiny ice crystals cover much of the sky. Each ice crystal acts like a miniature lens. Because most of the crystals have a similar elongated hexagonal shape, light entering one crystal face and exiting through the opposing face refracts 22 degrees, which corresponds to the radius of the Moon Halo. A similar Sun Halo may be visible during the day. The picture was taken in Lansdowne, Pennsylvania, USA. The distant planet Jupiter appears by chance just to the left of the Moon. Exactly how ice-crystals form in clouds remains under investigation.

[petuniasevan]

Vacation Announcement

I will be on vacation from June 2nd through June 9th.
If anyone would like to volunteer to post APOD during that time, please FReepmail me.
Otherwise the APOD will not be posted as I will be visiting relatives in California.

Here's an example of multiple halos and related phenomena around the Sun on a cold winter's day.

Here's a great web page for learning about atmospheric phenomena (and lots of great pics too!)

Atmospheric Optics

[petuniasevan]

[Jemian]

Brrrrrr!

The tropics are calling me.

[GodBlessRonaldReagan]

Saw a moon halo during this Winter's deepest freeze...

[Vets_Husband_and_Wife]

Gosh, I hope someone will be around at that time to post for you. If not, I'll just have to go directly to the Nasa site.

I admit I take advantage of just clicking on the site right here,..its so easy. But then everyone needs a vacation.. and YOU GO HAVE FUN!!!

FRegards, Vets

[firewalk]

Thanks for the ping