May 28, 2011

M13

The great globular cluster in Hercules, comprising about 300,000 stars packed into a rough sphere about 160 light years across. The cluster, the largest visible globular cluster in the Northern Sky is about 25,000 light years distant.


A 21 minute exposure. Note the small galaxy (IC4617) at the very top of the image. The galaxy is, of course, millions of light years distant.


M27 - The Dumbbell Nebula

A jewel of the summer sky, M27 is a planetary nebula easily identifiable due to its hourglass shape in the constellation Vulpecula (south of Cygnus).

The above image is a 30 minute exposure.

March & April 2011

The above image is a three hour exposure of the spiral galaxy M81 (sometimes called Bode's Galaxy, left) and the irregular galaxy M82 in Ursa Major.

The above image is a two hour exposure of the large spiral galaxy M101 (sometimes called the Pinwheel Galaxy) also in Ursa Major.

The above image is a combination of several images of M101, for a total exposure time of about four hours.

The Whirlpool Galaxy, M51. Total exposure time of three hours.

January 20, 2010

NGC 2244 - Rossette Nebula

Appearing in the constellation of Monoceros (the Unicorn), the Rossette Nebula (NGC 2237, 2238, 2239 & 2246) is a large, circular complex of pinkish nebulosity surrounding the open star cluster NGC 2244. The swirling waves of gas and dust in the nebula give it the appearance - and hence the name - of an open rose with glittering diamonds at its center. The nebula and cluster are about 5,200 light years away.

The above image combines exposures captured in December 2009 with additional exposures captured in December 2010 to create an image with a total exposure time of 227 minutes (almost four hours).

This image, taken on December 8, 2010, comprised 13, 240-second subexposures for a total exposure time of 52 minutes.

NGC 1499 - California Nebula

This is a large emission nebula appearing in the constellation Perseus. The nebula's unique shape suggests the outline of the state of California to many observers. NGC 1499 is about 1,000 light years distant.

The above image was composed from 14, 240-second subexposures, for a total exposure time of 56 minutes.

IC 434 - The Horsehead and Flame Nebulas

The famous horsehead nebula, appearing just south of Alnitak, the eastern-most star in Orion's belt, is one of the most recognized objects in the night sky (when seen in long exposure photography, of course). The horsehead itself is actually a jet of sooty dust that happens to appear in front of an cloud of ionized hydrogen gas (the pink glow). The orange-colored nebula that appears beneath the bright star in the images below is the Flame Nebula. This nebula is the result if ultraviolet light from the star Alnitak striking a nearby cloud of hydrogen gas and dust.

The above image combines subexposures taken in September, November and December 2009 and December 2010 to produce a image with a total exposure time of three hours and twenty one minutes (193 minutes).

This image was taken on December 9, 2010, and was composed of 12, 240-second subexposures, for a total exposure time of 48 minutes.

December 4, 2010

Some images from the last two months:

M42 - The Great Orion Nebula

The brightest nebula in the northern sky, easily visible to the naked eye as the "fuzzy star" in Orion's Sword, this vast emission nebula is actually a massive stellar nursery, and merely a blister on a larger cloud of gas that extends for thousands of light years across the constellation of Orion. The nebula's wispy structure results from hydrogen gas being scuplted by stellar winds coming from stars within the nebula itself. M42 spans 24 light years in diameter and is located about 1,300 light years away.

The above image comprises 35, 180-second subexposures taken on December 3, 2010, for a total exposure time of 105 minutes.

M1 - The Crab Nebula

This fame nebula in the constellation Taurus is all that remains of a star that went supernova. The light from the blast was observed by Chinese astronomers in 1054 AD. The nebula is located about 6,500 light years from Earth.

The above image is a crop of the larger image below.

This image was comprised of 50, 300-second subexposures taken in September, October and November for a total exposure time of over four hours.

M33 - The Triangulum Galaxy

Appearing in the constellation Triangulum, M33 is a large spiral galaxy seen face on. Part of the local group of galaxies, it is thought to be much smaller than either the Andromeda Galaxy or the Milky Way Galaxy, both of which have hundreds of billions of stars. M33 is thought to have less than 100 billion resident stars. Though large, the galaxy has a low surface brightness and is consequently difficult to see with telescopes.

This image was composed of 59, 300-second subexposures taken in August, September, October and November. Total exposure time was almost five hours.

NGC884 & NGC869 - The Double Cluster

These two bright open clusters have been known to skywatchers since antiquity, noted by ancient Greek astronomers. They can be seen with the naked eye on clear, dark nights in the constellation of Perseus, appearing as a fuzzy double star. A pair of binoculars or a small telescope will resolve the clusters into hundreds of stars. The clusters are believed to lie relatively close together about 7,000 light years away.

This image comprises 13, 300-second subexposures taken on October 2, for a total exposure time of over one hour.

September 19, 2010

IC 1396 - The Elephant's Trunk

This curling, meandering trail of dust and gas in Cepheus is part of a much larger nebula complex containing both emission and dark nebulae.

The above image is a closeup of the larger image below.

Both images were composed of 26, 300-second images taken on September 14, for a total exposure time of 130 minutes.

NGC 891

This galaxy, seen edge-on in the constellation Andromeda, is estimated to be 30 million light years distant.

This image was composed from seven, 300-second images.

NGC 6946

This image captures the galaxy NGC 6946 and the open cluster NGC 6939, visible in the same starfield in the constellation Cepheus. The galaxy lies 22 million light years away and is occasionally called the "Fireworks Galaxy" because astronomers have detected no less than nine supernova explosions inside it during the past century. The cluster is about 5,800 light years distant.

This image comprises 28, 300-second images, totaling two hours and ten minutes exposure time.

Summer Wrap Up

As any resident of the Northeastern U.S. can attest, the summer of 2010 was long, hot and sticky. July and August simmered unrelentingly. Even the handful of relatively haze-free evenings were so humid as to make imaging impossible or just plain uncomfortable. Nevertheless, I managed to obtain images of some of the summer sky's gems.

NGC 7380

This is an open star cluster embedded in a large emission nebula. Located about 7,000 light years away in the constellation Cepheus, the star cluster is about 110 light years across and is thought to be about five million years old.

This image is composed of 18, 240-second images taken on August 7 and 22, 180-second images taken on August 29, for a total exposure time of two hours and ten minutes.

The Iris Nebula

This blue reflection nebula is illuminated by light from its central star. Dark dust clouds surround the reflection nebula. Though the Iris Nebula is often cited as NGC 7023, that catalog number actually refers to a near by star cluster. The nebula's proper designation is LBN 487. Roughly six light years across, it is about 1,300 light years away.

This image was created from three and five minute exposures taken August 6 and 24, and September 5, 10, and 15. Total exposure time was just over four and a half hours.

NGC 6888 - The Crescent Nebula

This emission nebula appears in the constellation Cygnus. Located about 5,000 light years away, the nebula is the result of colliding waves of gas emitted by a Wolf-Rayet star.

This closeup image of the Crescent Nebula is a ninety minute exposure, combing images from this year and last.

This wider-field image comprises 26, 180-second exposures taken on August 14, 2010.

M52 & NGC 7635

The image below captures the open cluster M52 and the emission nebula NGC 7635, also known as the Bubble Nebula, in the constellation Cassiopeia.

This image was composed from 23, 180-second images, for an exposure time of around an hour and ten minutes.

June 2010

M20 - The Trifid Nebula

The Trifid Nebula is a large nebular complex that combines dark, reflection and emission nebulae, easily visible in the constellation Sagittarius (just north of the teapot's spout). It is one of the most beautiful objects in the summer sky.

This image combines exposures taken on April 19 and 24, May 6, and June 15, for a total exposure time of just over two hours.

M22

First noticed by astronomers as early as 1665, this globular cluster, which appears in the constellation Sagittarius, contains tens of thousands of stars spread over a mere 200 light year diameter. The cluster is about 10,400 light years from Earth and can be easily seen in binoculars or a small telescope.

This image comprises just three, 120-second exposures, for a total exposure time of just six minutes.

NGC 6960

This filamentary whisp of dust and gas in Cygnus is part of the Veil Nebula, a broken ring of nebulous arcs, all that remains of a massive star that went supernova between 5,000 and 10,000 years ago.

This image comprises eight, 120-second exposures, taken on May 10, and seventeen, 180-second exposures taken on June 6, for a total exposure time of 67 minutes.

The above image shows a wider field, capturing more of the surrounding star field. This image comprises 17, 180-second exposures, taken on June 6.

M8 - The Lagoon Nebula

Located about 6,000 light years away, the mighty Lagoon Nebula is a great stellar nursery visible to the naked eye under dark skies in the constellation Sagittarius.

This image is a 39 minute exposure, composed of thirteen, 180-second exposures.