10 September 2009

Galaxies and Nebulae and Clusters, Oh My!

After being rejuvenated from its space shuttle servicing mission last May, the 19-year-old Hubble Space Telescope is officially back in business. Engineers had spent the last three months focusing, testing, and calibrating. But now it’s back to photographing the universe like never before. Yesterday, NASA released the first stunning snapshots from the upgraded scope. They include a remarkable butterfly-shaped nebula (top left), a galaxy cluster as crowded as a subway in rush hour (bottom left), and a roiling stellar nursery (bottom right). Full details can be obtained by going to http://www.spacetelescope.org/news/html/heic0910.html.

As a nod to astronomer Edwin Hubble, I wish they had photographed NGC 2261 again as well, a comet-shaped cloud of gas located in the direction of the Monoceros constellation (left). While working on his doctoral thesis at Yerkes Observatory in Wisconsin around 1914, Hubble took a picture of this nebula and compared it with photographs taken earlier at other observatories. He noticed that his recent photo displayed distinct differences from previous ones, which proved that certain faint nebulae could change over time. It was his first major discovery. Today, this object, located within the Milky Way, is known as Hubble’s variable, a reflection nebula made of gas and fine dust fanning out from the star R Monocerotis. It's about one light-year across and lies about 2,500 light-years away.

NGC 2261 always held a fond place in Hubble’s heart. Soon after he arrived at the Mount Wilson Observatory as a staff astronomer in 1919, he got his first crack at the newly opened 100-inch telescope, what he called his “magic mirror.” It was on Christmas Eve, and he couldn’t have asked for a more fitting holiday present. The atmosphere was almost at its best, and it was also dark-sky time, the Moon having just set in the west. His best photograph of the night came when he aimed the giant scope at his variable nebula. From that point on, it became his observational “mascot.”

Later in his observing life, 1949, Hubble had the honor of being the first scheduled observer on the giant 200-inch Hale Telescope situated on California’s Palomar mountain. Needless to say, he got started by imaging his good luck charm, NGC 2261. Perhaps, Hubble Space Telescope astronomers should consider adopting this intriguing nebula as their mascot, too. Who knows, the luck might rub off. (Though from the look of these photos, maybe they don't need it.)

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