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.

May 12, 2010

M11 - The Wild Duck Cluster

This is an open cluster that appears in the constellation Scutum (the Shield). The cluster is notable for being extremely compact (for an open cluster). It contains about 2900 stars. While it is visible in small telescopes and binoculars, a larger instrument is needed to resolve the cluster's individual stars.

This is a twelve minute exposure.

May 6, 2010

M27 - The Dumbbell Nebula

A favorite of amateur astronomers, this planetary nebula in the constellation Vulpecula is easily visible as a faint, hourglass-shaped smudge in small telescopes and binoculars. Planetary nebulae result when older stars, unable to sustain their mass, blow off their outer layers, whose gas and dust expand outward, forming often spherical shaped clouds (hence the name, planetary nebulae). This process is called a nova. The dying star's core then contracts to form a white dwarf star, a diminutive remnant of its former glory. White dwarfs can continue to shine for billions of years. The Dumbbell Nebula is located about 1,300 light years from Earth. Astronomers estimate that M27 formed about 14,600 years ago.

The above image comprises 12, three minute subexposures, for a total exposure time of 36 minutes.

M8 - The Lagoon Nebula

Located about 5,000 light years from Earth, the Lagoon Nebula is a large emission nebula that appears in the constellation Sagittarius. Like M27, it is easily visible in small telescopes and binoculars. The nebula contains a number of dark clouds, called Bok Globules, in which proto-stars are thought to form. M8 appears in a particularly rich starfield; another famed emission nebula, M20, can be found just north of it.

This image was composed from 15, three minute subexposures, for a total exposure time of 45 minutes.

M17 - The Swan Nebula

This is a bright emission nebula that appears in the constellation Sagittarius. Astronomers estimate the nebula to be about 15 light years in diameter, though it appears to be part of a much larger cloud of interstellar material. It is located around 5,000 light years from Earth.

The above image is a 24 minute exposure.

April 24, 2010

The summer sky now rises well before dawn, offering an opportunity to capture a preview of its gems well before the season actually arrives...

M20

Know as the Trifid Nebula due to the dark dust lane that seems to divide the bright red cloud into three parts, this object has long been a favorite of both amateur and professional astronomers. For the amateur, it is relatively bright and thus easily located even with small scopes and even binoculars. Professional astronomers have been thrilled by the discovery that the Trifid combines reflection and emission nebulae, a star cluster, and contains a stellar nursery deep in its colorful clouds in which new stars are forming.

Added to Messier's catalog in 1764, the Trifid appears in a dense starfield in Sagittarius - the Lagoon Nebula (M8) lies just to the south. Astronomers place the nebula about 5,200 light years from Earth.

The above image comprises 11, 300-second subexposures, taken on April 19, and 11, 200-second subexposures, taken on April 24, for a total exposure time of 92 minutes.

M16

This is an open star cluster that lies amid an emission nebula, whose striking shape has led astronomers to dub it the Eagle Nebula. The intriguing structures of dust and gas at the nebula's center were imaged by the Hubble Telescope almost a decade ago, producing one of the Hubble's most famous images, "The Pillars of Creation," which showed enormous clouds of gas enveloping new born stars. The entire nebula is a stellar nursery. Astronomers estimate the nebula's age at 5.5 million years, and place it about 7,000 light years from Earth.

M16 is readily visible through binoculars or a small telescope.

This image is comprised of seven 300-second subexposures, for a total exposure of 35 minutes.

February 22, 2010

February brought a seemingly-endless series of heavy snowstorms to the East Coast, dropping more than two feet of snow on the New York area. This didn't leave much time for astronomy related activities. Still, I did manage to capture some of the more prominent clusters in the late winter/early spring sky.

M67

This open cluster in the constellation Cancer is noteworthy for being one of the oldest in the sky. It's stars have been estimated at between 3.2 and 5 billion years of age, making the cluster a little younger than our sun. The cluster is about 2,700 light years distant and contains about 100 stars.

This image is a 12 minute exposure.

M50

Located about 3,000 light years distant, this open cluster appears in the constellation Monoceros.

This image is a ten minute exposure.

M48

Located in the constellation Hydra, this open cluster is estimated to be about 300 million years old.


This image is a nine minute exposure.