December 30, 2009

End of the Year Roundup

December has brought clearer skies, but colder, even freezing, nights. In addition to imaging a few new targets, I also used the time to capture additional exposure time for some objects already imaged. Consider this a year-end wrap up.

M42

The Great Orion Nebula is such an appealing object that I can't resist coming back to it again and again. The image below combines sub-exposures of 300 and 400 seconds, taken on October 9, December 11 and December 16, for a total exposure time of 143 minutes.

The long exposure time brings out the nebula's dust lanes and inner structure. Note the contrasting colors in the Running Man Nebula (upper right of image).

NGC 2264 - The Cone Nebula & Christmas Tree Cluster

The constellation of Monoceros, the Unicorn, appears directly east of Orion and contains dense starfields littered with gleaming clusters, fuzzy nebulae and great swaths of nebulosity. Among its many gems are a pair objects that have received a single New General Catalog (NGC) designation: the Cone Nebula and the Christmas Tree Cluster (NGC 2264).

The Cone Nebula, first noticed by William Herschel in 1785, is a combination of overlapping absorption (dark) and emission (bright) nebulae, which give the nebula complex its unique shape. The nebula is associated with a cluster of young, bright stars, often referred to as the Christmas Tree Cluster. Both lie about 2,700 light years away.

The image below captures both the Cone Nebula (center left) and Christmas Tree Cluster (center right) amid a particular rich starfield. Note the waves of nebulosity in the upper right part of the image.

The above image is a combination of sub-exposures taken on October 19 & 25 and December 9 & 11, for a total exposure of 251 minutes.

IC 434 - The Horsehead Nebula

Like M42, the Horsehead Nebula demands repeated attention, and very long exposures to draw out all of its hidden detail. The image below combines sub-exposures taken on September 19, November 28 and December 9, for a total of 196 minutes.

M97 - The Owl Nebula & M108

As the Ursa Major (the Great Bear - 0r Big Dipper) begins to appear over the treeline after midnight, the coming months will be a good time to start imaging the many galaxies that appear within its borders. Among Ursa Major's many treasures is M97, a planetary nebula, that appears as a pale disk with two eye-like dark spots that give it its facelike appearance. The nebula lies about 2,600 light years away and formed around 6,000 years ago. It appears near a barred spiral galaxy, M108, which is seen edge on. M108 lies about 45 million light years away.

The above image had an total exposure time of about one hour.

NGC 2237 & 2244 - The Rosette Nebula & Cluster

Given the wonderful complexity of this nebula in Monoceros (the Unicorn), I figured it would benefit from additional exposure time. The image below combines 35, 300-second sub-exposures taken on October 18 and December 16, for a total exposure time of 175 minutes (almost three hours).

M1 - The Crab Nebula

The Crab Nebula is the result of a supernova (the explosive death of a large star) that was observed on Earth, as a suddenly appearing bright star, in 1054. The nebula appears in the constellation Taurus (The Bull) and lies about 6,500 light years away and contains the Crab Pulsar, a rapidly rotating neutron star that releases radiation in frantic pulses. The pulsar is all that remains of the massive star whose death gave birth to the nebula. The Crab Pulsar was the first pulsar so identified by radio astronomers.

The image below shows M1 in its starfield.

In order to better show the nebula's structure, I have cropped the image to highlight the nebula itself.

Both images comprise 20, 300-second images take on October 25 and December 16, for a total exposure time of 100 minutes.