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.

2013 October 14
See Explanation.  Clicking on the picture will download
 the highest resolution version available.

High Noon Analemma Over Azerbaijan
Image Credit & Copyright: Tunç Tezel (TWAN)

Explanation: Is the Sun always straight up at noontime? No. For example, the Sun never appears directly overhead from locations well north or south of the Earth's equator. Conversely, there is always a place on Earth where the Sun will appear at zenith at noon -- for example on the equator during an equinox. Turning the problem around, however, as in finding where the Sun actually appears to be at high noon, is as easy as waiting for midday, pointing your camera up, and taking a picture. If you do this often enough, you find that as the days march by, the Sun slowly traces out a figure eight on the sky. Pictured above is one such high noon analemma -- a series of pictures always taken at exactly noontime over the course of a year. The above fisheye image, accumulated mostly during 2012, also shows some buildings and trees of Baku, Azerbaijan around the edges.

Tomorrow's picture: great carina

< | Archive | Index | Search | Calendar | RSS | Education | About APOD | Discuss | >

Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (UMCP)
NASA Official: Phillip Newman Specific rights apply.
NASA Web Privacy Policy and Important Notices
A service of: ASD at NASA / GSFC
& Michigan Tech. U.