Astronomy, Photography and Weather

General Category => Astronomy & Space => Topic started by: rjgjr on January 20, 2011, 05:17:08 pm



Title: Wolf Moon Setting
Post by: rjgjr on January 20, 2011, 05:17:08 pm
After last nights moonrise being clouded out, I awoke to beuatiful skies this morning. I went down to Kissing Rock and grabbed these shots. In the first one, can someone tell me what causes the crep-type rays in the west at sunrise. Is it still cloud related?
Enjoy!

(http://i54.tinypic.com/2iig0f5.jpg)


(http://i53.tinypic.com/20qcry0.jpg)


(http://i56.tinypic.com/2zsrwn6.jpg)


(http://i54.tinypic.com/2md5n60.jpg)


Title: Re: Wolf Moon Setting
Post by: martinastro on January 20, 2011, 05:24:10 pm
Stunning!!, the first image is a winner. What you have there are anti-crepuscular rays which converge directly opposite the sunset, so in this case in the morning the rising sun in the E would produce rays at the anti-solar point in the W. Here's more...

http://www.atoptics.co.uk/atoptics/anti1.htm

http://en.wikipedia.org/wiki/Anticrepuscular_rays

Yes, they are caused by clouds and distant hills/mountains. Very nice catch Richard  :)


Title: Re: Wolf Moon Setting
Post by: rjgjr on January 20, 2011, 07:34:58 pm
Thanks for the interesting links Martin!


Title: Re: Wolf Moon Setting
Post by: Paul on January 20, 2011, 09:23:54 pm
Lovely shots Richard. Just to add a bit of technical info - you'll remember that the partial eclipse of 4th January was a case where the Moon's shadow missed the Earth by being too far North. Look at the focus of your anti-crepuscular rays and you'll see they point to the North of where the Wolf Moon is. This is because 14 days later, the Moon is now South of the ecliptic  as it was North at the time of the eclipse.

Orbital mechanics in action!

Paul.


Title: Re: Wolf Moon Setting
Post by: JohnC on January 20, 2011, 09:35:22 pm
Lovely shots Richard, the Pacific serves you well.

Hopefully, will be adding mine tomorrow .


Title: Re: Wolf Moon Setting
Post by: rjgjr on January 20, 2011, 10:07:45 pm
Looking forward to your shots as always John.
Thanks for the extra technical info Paul. Like a lot of folks, I take for granted what is really behind everything that goes on in the World and Universe, I should take the time to read a little more.


Title: Re: Wolf Moon Setting
Post by: markt on January 22, 2011, 10:20:06 am
Fantastic images Richard.  Yes, they're anti - crepescular rays.  I saw these when I was in Iceland for the first time in absolutely years.  Great point about the orbital mechanics of it all Paul - I can see this image is going to have some discussion in my GCSE astronomy class next week ;)