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.

2000 September 29 September Sky Credit & Copyright: Stan Richard

Explanation: Star clusters, planets, and a red giant posed for this portrait of the night sky from rural Jasper County, Iowa, USA. Astrophotographer Stan Richard recorded the four minute time exposure looking east around midnight on September 3rd at Ashton-Wildwood Park. To avoid star trails, his camera was mounted on a barndoor-style tracker to compensate for the Earth's rotation. Can you identify his celestial subjects? (Click on the image for a labeled version.) The Pleiades and Hyades, the closest open or galactic star clusters to the Sun, should be recognizable to beginning stargazers. Of course gas giant Jupiter rules as the brightest object in the picture and the largest planet in the Solar System, but second largest planet Saturn is also visible nearby. For sheer size cool red giant star Aldebaran is more impressive though, spanning about forty times the diameter of the Sun. Sixty light-years away and yellowish in this picture, Aldebaran is known as Alpha Tauri, the brightest star in Taurus, the Bull.