By Patricia Daukantas
When OPN described the Large Binocular Telescope (LBT) in an article last September, only one of the twin telescopes was up and running. Last week, the LBT team announced that the 8.4-m telescopes, mounted side by side, have achieved “first binocular light,” meaning that they took their first image as a working pair.
And what an image! The LBT looked at a spiral galaxy known as NGC 2770 and produced a photo of a sight that would be simply impossible to see with bare human eyes. One of the LBT’s scopes is optimized for ultraviolet and short-visible wavelengths of light; the other, for red and infrared. Astronomers photographed the galaxy with both instruments and produced a false-color image of wavelengths ranging from 324 nm to 0.9 µm.
Why bother to look at all these wavelengths? Different bands allow astronomers to see different objects—from young stars much hotter than the Sun to cool gas clouds. Many of the objects that emit in the ultraviolet or infrared are either very young or very old (well, by astronomical standards).
Much more detail about the LBT and the optical science behind the image, plus a gallery of photos of the twin telescopes, is in this press release.
Using both LBT mirrors, this First Binocular Light image shows a false-color rendition of the spiral galaxy, NGC 2770. The galaxy lies 102 million light years from our Milky Way (a relatively close neighbor), and has a flat disk of stars and glowing gas, tipped slightly toward our line of sight. The image displays ultraviolet, green and deep red light in the same composite, showing the detailed structure of hot, moderate and cool stars in the galaxy.
2008-03 March, Astronomy, Astrophysics