This image is comprised of 14, 300-second subexposures, for a total exposure time of 70 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). 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.
M97 - The Owl Nebula & M108
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.
Six, 300-second subexposures were combined to create this 30 minute exposure.
M41
As dawn approaches, the winter sky begins to give way to the constellations of Spring, now rising just before the sun. NGC 2903 is a fine barred-spiral galaxy, seen at a tilt, in the western part of the constellation Leo. Discovered by William Herschel in 1784 - who thought it to be a nebula - it remains something of a mystery why Charles Messier never included it in his famed catalog. The galaxy is bright enough to have easily been within the capability of his telescopes, and he noted at least four other galaxies in Leo (M65, 66, 95 & 96). Modern astronomers have estimated NGC 2903 to be 20.5 million light years distant.
In addition to its fine appearance when viewed with binoculars or a small telescope, M46 appears to contain a surprise - a small planetary nebula, NGC 2438, which appears as small colored disk at the cluster's edge. Astronomers consider this to be more appearance than actual association since the nebula appears to be moving at a different speed than the cluster, and since the cluster's member stars are too young to have gone nova (the death throes of older stars, which produces planetary nebulae). It is most likely that the nebula lies in front of M46 and simply appears to be part of it.
The image below is a crop of the preceeding image, showing NGC 2438 near the upper middle of the frame, at the top edge of the cluster's core.
The above images were comprised of five, 300-second subexposures - a total exposure time of 25 minutes.
M44
This a large open cluster in the constellation Cancer, also known as the Praesepe (Latin for Manger) or Beehive Cluster. M44 was first noted by Greek and Roman astronomers; Galileo viewed it with his homemade telescope as early as 1609; more than 150 years later Charles Messier added it to his catalog.
M44 has about a thousand member stars, but its members have dispersed over a fairly large area over the eons. It is about 577 light years away and occupies an area larger than the full moon. The cluster is best viewed with binoculars or a telescope with low magnification and a wide field of view.
Four, 300-second subexposures were combined to create this 20 minute exposure.
This spectacular open cluster appears in the constellation Gemini, named for the twins Castor and Pollux from Greek mythology. The cluster can be found easily with binoculars or a small telescope by sweeping near the three "foot stars," Eta, Mu and Nu Geminorum. This cluster was first noted by the French astronomer Phillippe Loys de Cheseaux as early as 1745, and was added to Messier's catalog about 20 years later. Astronomers estimate M35 to be about 110 million years old; the cluster contains between 200 and 500 stars and is about 2,800 light years away.
The image below captures not only M35, but also the smaller cluster NGC 2158 (lower middle of frame), a significantly more compact cluster thought to be about a million years old and about 16,000 light years distant.
This image is comprised of six, 180-second subexposures, for a total exposure time of 18 minutes.
This image comprises three, five minute sub-exposures, for a total exposure time of 15 minutes.M37
This cluster is considerably larger than M36, containing roughly 500 stars spread across a 25-light year diameter. M37 is located around 4,400 light years away and is thought to be about 300 million years old.
M38
Located about 4,200 light years away, M38 has about the same diameter of M37 (around 25 light years), but appears to contain fewer member stars. NGC 1907, a smaller open cluster that appears near M38 is captured in the same field at the lower left of the image below.
