July 13 2011 Astronomy Newsletter
Here's the latest article from the Astronomy site at BellaOnline.com.
Cats in the Sky
There are three constellations named for dogs, but what about cats in the sky? There is astrocat Felicette who went into space and returned safely to Earth, but also constellations of big cats and a paw print 50 light years across.
*Neptune discovered a year ago*
Johann Galle at the Berlin Observatory recorded the discovery of Neptune on September 23, 1846. Earth time. Yesterday, July 12, was the first anniversary of the discovery. Neptune time.
I don't have any cake, but here's a link to a new set of Hubble Space Telescope pictures of Neptune: http://www.nasa.gov/images/content/569227main_hubble-neptune-670.jpg
The four pictures, taken four hours apart, cover a full Neptunian day. Blue, red and infrared filters were used. The blue is methane in the atmosphere which absorbs red. The pink bits are high altitude clouds reflecting infrared.
There is more about Neptune in the following articles:
"Uranus and Neptune Twin Planets" http://www.bellaonline.com/articles/art39799.asp
"Neptune Facts for Kids" http://www.bellaonline.com/articles/art33048.asp
*Hubble and the Cat's Eye Nebula*
In this week's article I mentioned that the Hubble picture of the Cat's Eye Nebula had been enhanced. Nebulae, even when reflecting starlight, are quite tenuous and their colors tend to be pale. However color contrasts can be used to show structure. If you'd like to know what they did to the Cat's Eye Nebula picture, there's a short explanation at
That's all for now. Wishing you clear skies.
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