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Astronomical Observatory: Cool Images

Images: Supernova in the Whirlpool Galaxy

Supernova in Whirlpool Galaxy in July 2005 Whirlpool Galaxy in April 2004

Two images of the Whirlpool Galaxy from Calvin telescopes.
Left: Monochrome image by Andrew Butler in July 2005 (details below). Right: Color image by Phil Ammar in April 2004 (more info).

A beautiful spiral galaxy gave astronomers a rare treat in late June 2005 – a massive star ejected its outer layers in a violent explosion known as a supernova. This explosion was caused by the collapse of the star's iron core, which will either form a neutron star or a black hole. The galaxy, known as M51, is in the constellation Canes Venatici and is one of the most well-known galaxies of all. So naturally, Wolfgang Kloehr, an amateur astronomer from Schweinfurt, Germany, decided to image it on the night of June 27. After taking several exposures, he noticed a “small bright point” that was not in his reference image. Following his suspicions, he submitted his data to the Central Bureau for Astronomical Telegrams (CBAT). After a few days of waiting, his “small bright point” became known as supernova 2005cs.

In July 2005, student Andrew Butler photographed the galaxy using the Calvin Observatory telescope on campus and clearly detected the supernova. He found little variation in its brightness between July 14, 2005 and July 28, 2005, in agreement with professional astronomers.

More information on the supernova:
Wolfgang Kloehr's Discovery Log. Click on “english” next to “Discovery Story”.
Supernova in M51,Sky & Telescope, July 8, 2005
The Whirlpool's Supernova Surprises, Sky & Telescope, July 28, 2005

Processing Details: Andrew Butler took 105 images (240 seconds each) in the clear filter on seven nights from July 14 to July 28. He calibrated the data by subtracting a dark image and dividing by a flat image. He selected the 53 best exposures (a total of 3.5 hours of exposure time), aligned them, and combined them to make the above left image.

Orientation and scale: North is up and East is to the left. The image is 7.2 by 5.2 arcminutes. The galaxy core has celestial coordinates 13h29m53s, +47d11'48" (epoch 2000), which is 3.6 degrees southwest of Alkaid, the star at the end of the handle of the Big Dipper. The disk of the Whirlpool is some 40,000 light years across and approximately 35 million light years away from Earth.

Content updated Sept 7, 2005.





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