Home » News & Blogs » Gems in the Sky
Bookmark and Share
Sky Lights

Gems in the Sky

3 Mar 2014, 07:01 UTC
Gems in the Sky
(200 words excerpt, click title or image to see full post)

This image shows the “Jewel Box Cluster” (official designation NGC 4755). It’s an open cluster of stars 6400 light years from Earth in the constellation Crux (Latin for “cross”). Crux is a southern hemisphere constellation, and can’t be seen farther north than around latitude 25° N. It was given the name “Jewel Box” by astronomer John Herschel in the 1830s, who thought it looked like a piece of exotic jewelry.
The Jewel Box contains over a hundred stars displaying many different colors: blue, red, orange, and yellow are all visible. Blue stars are the brightest, and much larger and hotter than our Sun. Dim red stars are smaller and cooler than our Sun. Some people are surprised to learn that stars have colors — to the casual observer, all stars are just white points of light in a black sky. But if you take the time, allow your eyes to become dark-adapted, and look closely, you’ll see many (pastel) shades. Binoculars will help. See my Oct 17, 2011 post for more about star colors.
Amateur astronomer George O. Pitcovich wrote a poem about star colors. I share it here, as George would have wanted. He passed away in 1986, but ...

Latest Vodcast

Latest Podcast

Advertise PTTU

NASA Picture of the Day

Astronomy Picture of the Day