Visible All-Sky Survey
Visible All-Sky Survey
| Group Name | mwVis |
| Reference | Axel Mellinger (Universitaet Potsdam) |
| Prepared by | Ryan Wyatt (AMNH/Hayden) |
| Labels | No |
| Files | mw-visible.speck |
| Dependencies | mellinger-optmw.sgi |
| Wavelength | 400-700 nm |
| Frequency | 750,000-430,000 GHz |
In ancient times, our ancestors knew of the stars; the “wandering stars,” or planets; and the Milky Way. Aside from the occasional comet, “guest star” (supernova), or aurora, these were the only cosmic features visible to them.
The Milky Way has been the subject of many myths and legends. The Greeks believed it to be a river of milk pouring from the breast of Hera, the wife of Zeus, and called it a “galaxy,” from the Greek word for milk. The Romans called it the Via Lactea, or the Milky Way. But it was not until 1610 that Galileo first observed this faint band of light with his telescope, discovering that it was composed of innumerable faint stars.
In the past 400 years, astronomers and philosophers have speculated about the nature of this star system. It was not until the 20th century, though, that astronomers began to understand the nature and structure of our Galaxy, by looking at that band of light across our sky and comparing it with other “island universes,” like the Andromeda Galaxy.
Image Features
Several features of this band of light become obvious upon inspection (particularly if you increase its alpha value). Toward Galactic center [turn on the Galactic coordinates and look toward (l, b) = (0, 0)o] you will see the brightest part of the Galaxy. In this direction, looking toward Scorpius and Sagittarius, is the center of the Galaxy. The bright haze is the light from millions of stars; the dark lanes are foreground dust, obscuring our view. Relative to the rest of the Milky Way band, the center forms a bulge of light, whereas the rest of the band appears thinner.
If you turn to look in the opposite direction, toward Orion [(l, b) = (180, 0)o], you will see that the Milky Way is not too bright on this side of the sky. Here we look out of the Galaxy through what remains of the Galactic disk between the Sun and its outer edge.
This image is composed of many photographs of the sky, carefully knitted together in this giant mosaic. The stars have been removed for the most part, but the bright stars show some residual light.
© 2002-2005 American Museum of Natural History
Last Modified: 2007-12-19 by Brian Abbott