Sunday, November 23, 2014

Phantom Sun or Sun Dog


This afternoon @ Averbode, I could observe a beautiful sun dog or phantom sun. A Sun dog or phantom sub is a member of the family of halos. These are created by light interacting with ice crystals in the upper regions of the atmosphere. Sun dogs appear mostly as two subtly-colored patches of light (with red nearest the sun) to the left and right of the sun, approximately 22° distant and at the same elevation above the horizon as the sun. Best observarion time is when the sun is low above the horizon.
Both pictures are taken with Nikon D60 using a AF-S Nikkor DX 18-200.



Astronomical news

More astronomical information or links to websites you can find on my page Usefull Links.
An interesting website with the most recent and latest astronomical news is Astronieuws.nl.
The information shared is in the Dutch language, but they reference the original sources.

Thursday, October 30, 2014

Double rainbow explained and Alexander's dark band.

A rain droplet functions both as a mirror and prism.

As the first, primary, rainbow is caused by refraction and reflection of sunlight within rain drops, the secundary rainbow will show up when sunlight is reflected twice within the droplet. This also explains the reason why we see the reversed order of the colors. Because of the extra reflection and thus light gets lost, we see the secundary rainbow less bright than the primary rainbow.

Another phenomenon is the area between the primary and secundary rainbow. This area is typical darker and called Alexander's band or Alexander's dark band. This optical phenomenon was the first time described by Alexander of Aphrodisias, 200AD.






Saturday, October 18, 2014

Startrail Summer triangle

Startrail of the summer triangle. This triangle is made by the brightest stars Vega, Altair and Deneb of the constellations Lyra, Aquila and Cygnus. Picture taken using by Nikon D60 and pictures stacked using Startrail.de and final modified using CS4.



Usefull Links

More astronomical links available. See my "Usefull Links Page" 

Record High Temperature

Today, October 18 2014, a record high outside temperature was registrated in Belgium. The previous record was recorded 100 years ago. In Averbode a temperature of 25,5°C was measured around 17h08.