Astronomy Picture of the Day 12-22-03

Explanation: Why does the Andromeda Galaxy have a giant ring? Viewed in ultraviolet light, the closet major galaxy to our Milky Way Galaxy looks more like a ring galaxy than a spiral. The ring is highlighted beautifully in this newly released image mosaic of Andromeda (M31) taken by the GALaxy Evolution Explorer (GALEX), a satellite launched into Earth orbit in April. In the above image, ultraviolet colors have been digitally shifted to the visual. Young blue stars dominate the image, indicating the star forming ring as well as other star forming regions even further from the galactic center. The origin of the huge 150,000-light year ring is unknown but likely related to gravitational interactions with small satellite galaxies that orbit near the galactic giant. M31 lies about three million light-years distant and is bright enough to be seen without binoculars toward the constellation of Andromeda.

Here is M31 in visible light:

Right Ascension	00 : 42.7 (h:m)
Declination	+41 : 16 (deg:m)
Distance	2900 (kly)
Visual Brightness	3.4 (mag)
Apparent Dimension	178x63 (arc min)

The surface brightness of the Andromeda Galaxy (M31) is fairly high, but still the total magnitude is spread out over it, so it does appear faint. You need dark skies to spot this one with the naked eye. Binoculars will reveal a fuzzy oval patch, and in a decent 'scope expect a view you won't forget.

Finder charts below:

Below is an image of M31 from a 135mm telephoto lens on 400 ASA film, 15 minutes guided exposure.

Yes, the Andromeda Galaxy is visible at this time of year. At my latitude it is nearly overhead at 6:30 PM local time on 12-22-03.

In fact, from this latitude it is visible at night for quite a few months; one can find it at some time during the hours of darkness from the beginning of June to mid-March!

I mentioned this in an APOD in passing re: the renamed Space Infrared Telescope, but decided to post this article.

NASA's last Great Observatory gets new name
NASA NEWS RELEASE
Posted: December 18, 2003

NASA Administrator Sean O'Keefe today announced NASA's Space Infrared Telescope Facility has been renamed the Spitzer Space Telescope. It was named in honor of the late Dr. Lyman Spitzer Jr., one of the 20th century's most distinguished scientists.

Lyman Spitzer, Jr. Credit: Denise Applewhite/Princeton University

Spitzer's pioneering efforts to put telescopes in space led to two successful space missions, including the Hubble Space Telescope. NASA also released the telescope's first dazzling observations.

"The Spitzer Space Telescope takes its place at the forefront of astronomy in the 21st century, just as its namesake, Dr. Lyman Spitzer Jr., was at the forefront of astronomy in the 20th," said NASA's Associate Administrator for Space Science Dr. Ed Weiler.

The telescope was launched August 25, 2003, from Cape Canaveral Air Force Station, Fla. The Spitzer Space Telescope uses state-of-the-art infrared detectors to pierce the dense clouds of gas and dust that enshroud many celestial objects, including distant galaxies; clusters of stars in formation; and planet forming discs surrounding stars. It is the fourth of NASA's Great Observatories, a program that also includes the Hubble Space Telescope, Chandra X-ray Observatory and the Compton Gamma Ray Observatory.

The new name was chosen after an international contest sponsored by NASA. More than 7,000 names and supporting essays were submitted, with more than a third coming from outside the United States. Jay Stidolph, 28, a Canadian resident of Fort Nelson, British Columbia, submitted the winning entry.

Spitzer (1914-1997) was the first to propose, in 1946, placing a large telescope in space to avoid the blurring effects of Earth's atmosphere. He then devoted the next 50 years of his career to making this vision a reality. His efforts led to two successful NASA space telescopes: the Copernicus satellite and the Hubble Space Telescope. He also made significant contributions to the fields of stellar dynamics, the interstellar medium and plasma physics.

Spitzer served on the faculty of Princeton University for 50 years. He received numerous awards, including the Catherine Wolfe Bruce gold medal (1973); the National Academy of Sciences' Henry Draper Medal; the first James Clerk Maxwell Prize for Plasma Physics by the American Physical Society (1975); the Gold Medal of the Royal Astronomical Society (1978); the National Medal of Science (1979); and the Crafoord Prize of the Royal Swedish Academy (1985), the equivalent of the Nobel Prize for fields excluded from those awards.

In addition to being an outstanding scientist, Spitzer was an exceptional teacher, well regarded by his colleagues and students. He authored two popular reference books: Physics of Fully Ionized Gases and Diffuse Matter in Space.

Considered to be a man of incredible discipline, diligence and politeness, Spitzer also loved to mountain-climb and ski. He was a member of the American Alpine Club. His wife, Doreen Canaday Spitzer, four children and 10 grandchildren survive him.

NASA's Jet Propulsion Laboratory, Pasadena, Calif., manages the Spitzer Space Telescope mission for NASA's Office of Space Science, Washington. Science operations are conducted at the Spitzer Science Center at the California Institute of Technology in Pasadena.

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