Primordial Light: Deep Sky

Primordial Light: DEEP SKY Page 1

A Long Time Ago in a Galaxy Far, Far Away...

a great number of photons were released by hundreds of billions of stars. Those photons traveled for 20.5 million years and the first solid thing they encountered was the primary mirror on my telescope. The primary mirror directed the photons to a secondary mirror, which directed them to a CCD sensor on my camera. The galaxy is named NGC 2903, and it is a barred spiral galaxy that is 20.5 million light years from Earth. Here is another photo of this galaxy, along with a galaxy about which little is known.

How can photons travel 20.5—or 150—million years when the Universe is only 6,000 years old?

The Horse Head and Flame Nebulae

The Alnitak region of the constellation Orion, photographed on December 2, 2008. The bright star is Alnitak, which is plainly visible to the unaided eye on winter evenings as the left-most star in Orion’s belt. The famous Horsehead and the Flame Nebula are here, as well. The red nebula that delineates the Horsehead is known as Orion B, or NGC 2024. The blue nebula near bottom center is NGC 2023, the purplish nebula to the left of Alnitak is IC 432, and the dim blue nebula above IC 432 is IC 431. The Flame Nebula and the Horsehead are approximately 1,500 light years from Earth, and they are part of the same huge complex of nebulae that glow in and around Orion. The halos around the bright stars and the diffraction spikes are artifacts of the Takahashi Epsilon 180 reflecting telescope that I used to make this image. The camera was a Canon 40D modified by Hap Griffin. Other equipment included a Starfish guide camera on an 89 mm Questar Duplex and a RoboFocus for the Takahashi. The mount was an Astro-Physics 1200GTO. Nine 10-minute exposures. Made on a Mac.

NGC 7000, The North American Nebula

I made this photo between August 31 and September 7, 2007. The largest mass is NGC 7000, The North American Nebula. It isn’t difficult to imagine the outline of North America in this nebula, especially Florida, the Gulf of Mexico, and Central America. On the right is IC 5067, The Pelican Nebula. His knobby head, dark eye, and bill are quite plain.

The word nebula comes from Latin, where it means mist. In German, Nebel means fog. From the Latin word we derive nebulous, which means unclear, vague, or ill-defined. That's a very apt description of the appearance of a nebula in a telescope. Amateur astronomers often call them faint fuzzies because that's what they mostly look like through the eyepiece of a telescope—faint, indistinct patches of light. It takes a photograph to give some sense of the true appearance and extent of a nebula. The plural of nebula may be given as nebulae or nebulas.

NGC 7000 consists of vast clouds of hydrogen gas and dust. The hydrogen is glowing because it is being bombarded by radiation from stars, many of which are unseen in this photo because they are blocked by the hydrogen and/or the dust. The radiation causes the hydrogen to emit photons. That makes NGC 7000 an emission nebula, i.e., one whose gas emits light due to bombardment by radiation from stars. Another kind of nebula is a reflection nebula. Much of the light in this photo is in a very narrow part of the red end of the spectrum known as the Hydrogen Alpha (Hα) band, and the sub-frames that make up this photo were taken through a Hydrogen Alpha (Hα) filter that transmits only a 4.5 nanometer-wide portion of the spectrum centered at 656.3 Ångströms. For the most part the dark areas are not black sky, but dark nebulæ, clouds of dust that obscure the light of the glowing hydrogen gas and the background stars in some areas. There are also at least three named star clusters in this photo. The most obvious is NGC 6997, which is a large, widely spaced open cluster situated due north of the “Florida” peninsula. NGC 7000 is about 65 light years across, while the entire nebula complex (which does not fit in this image) is 130 light years across. This nebula complex is believed to be 1,900 light years (LY) from Earth. That’s next door relative to the scale of the Milky Way Galaxy (100,000 LY across), not to mention the large scale of the Universe itself. Still, the photons that made this image traveled for 1,900 years without hitting anything until they encountered my telescope mirror. This picture is special to me because it is a First Light image, that is, the inaugural image from a new telescope. That telescope, a Takahashi Epsilon 180ED, and the SBIG STL-11000M camera that I used to make this picture, are shown on this page. I believe that this is also my first photo with in the light of Hydrogen Alpha. Update: I made a new Hα photograph of the NGC 7000 region on 24-25 September, 2010.

M42, The Orion Nebula

Orion, the Hunter, is a winter constellation. It is perhaps the best-known constellation in the sky because it is positioned astride the Celestial Equator and it is visible from the entire populated Earth. Orion's asterisms—its star patterns—are distinctive. In addition to the Hunter's arms and legs there is his unmistakable belt of three bright stars, and below the belt is his sword. Take a look at the sword with your unaided eye. It appears to consist of three stars, but practically the entire sword is shown above. At the top is a cluster of stars in a patch of blue nebulosity called the Running-Man Nebula. That star cluster is the top "star" in the sword. Below it is M42, the Orion Nebula, the brightest part of which is lit by a cluster of very hot stars called the Trapezium that formed recently from the gas in the Nebula This cluster is the middle "star" in the sword. The brighter of the two stars at bottom is the bottom star in the sword. With simple binoculars you can see that the middle star is fuzzy and indistinct rather than a sharp point like other stars. In other words, you can see some of the M42 nebula through your binoculars. Seen through a small telescope the Orion Nebula appears pale green in color. M42 is about 1,600 LY from Earth. Practically the entire constellation of Orion is embedded in an enormous molecular cloud that emits visible radiation—a nebula, in other words, though it is much dimmer than M42. Rob Gendler, one of the best amateur astrophotographers in the world, was perhaps the first to record the extent of this cloud in this stunning photograph called the Orion Deep Field. Telescope: Tele Vue 76; camera: Canon 20D. January 28, 2006.

M45, The Pleiades Star Cluster and Nebulosity in Taurus

M45 consists of the The Pleiades star cluster and the surrounding nebulosity. The Pleiades, or Seven Sisters, is probably the most famous cluster in the sky because it is easily seen with the unaided eye and has been known since antiquity. The Seven Sisters are the daughters of Atlas and Pleione. I'm not going to go into the whole mythology surrounding the Pleaides because you can read it here. The nebulae in M45 are reflection nebulae, i.e., the gas and dust are not generating light due to bombardment from stellar radiation as in NGC 7000 and M42, but are reflecting light from the stars in the nebula. The light is bluish because the nebulosity contains much carbon dust. It was thought that the stars in the Pleiades Cluster formed from the nebulae that surround them, but that is apparently not the case; it seems that the cluster is moving through an existing cloud of dust and gas as it makes its way around the center of the galaxy. The stars in the Pleaides Cluster are very young, no more than 150 million years (compared to 4.5 billion years for our Sun). The distance to the Pleaides Cluster is about 440 light years, which makes them very near to us relative to the size of the Milky Way. RGB. Telescope: Takahashi Epsilon 180ED; camera: SBIG STL-11000M. September 16, 2007

The Rosette Nebula and Star Clusters

The Rosette Nebula in the Light of Hydrogen Alpha

There are a number of catalogued features in and around this nebula. One of the most prominent is the open star cluster, NGC 2244, that is located in the center of the nebula. Radiation pressure (stellar wind) from the stars in this cluster has hollowed out the center of the nebula. We are fortunate that the Rosette is too dim to be seen by the unaided eye because the nebula is very large and it is not very far away, and it would appear about five times as wide as the full Moon. It would be an awesome sight, to be sure, but it would dominate the winter sky to the detriment of other beautiful objects such as the Horsehead Nebula in Orion and M42, the famous nebula in Orion’s sword. Takahashi Epsilon 180ED, SBIG STL-11000M. 40 min. January 1, 2008

The Rosette Nebula and Star Clusters in Color

The Rosette Nebula in Color

I made this photo on December 3, 2008, using the same equipment as I used for the Horsehead. This photo is rotated 90 deg. CCW relative to the Hydrogen Alpha version above. Four 10-minute exposures

The Horsehead and Flame nebulae in Orion in Hydrogen Alpha

February 1, 2008

The Flame is approximately 1,500 light years from Earth and the Horsehead is about
1,600 light years distant. The bright star is Alnitak, the left-most star in Orion’s Belt.

The clouds of dust and gas in this image are shaped by the same force that
shapes clouds in our sky—wind. Many of these clouds even resemble the clouds
in our sky. But the wind that shaped these clouds is not the wind in which you
would fly a kite.* These clouds are shaped by stellar wind— radiation (sub-atomic
particles emitted by stars acting on the dust and gas in the same way that earthly
winds act upon clouds of water vapor). The dynamics are virtually identical in each case.

*It has been suggested that a spaceship launched from Earth by means of a conventional
rocket could, after it has escaped the Earth's gravity well, unfurl a huge sail made
of very lightweight yet very strong material. The sail would be black on one side and
as reflective as possible on the other side. The black side would be kept facing the Sun
at all times. Photons from the Sun would strike the sail and cause the spacecraft to
accelerate. These photons are simply sunlight, and not the charged particles that
comprise the solar wind, but the stellar wind brought this to mind. While there is no
reason such a spacecraft could not be built, thus far such spacecraft are limited to the
realm of science fiction. Acceleration would be exceedingly slow, but if you had
a few billion years to spare you could probably travel a long way using the light
of different suns along the way.

This is another Hydrogen Alpha image. It is comprised of six 10-minute exposures.
My experience is that the Flame Nebula can be seen with a fairly modest telescope, but
the photographically bright nebula that lies behind the Horsehead is very dim visually
and requires a large telescope. I have seen the Flame through a telescope eyepiece,
but not the Horsehead. I used a Takahashi FSQ-106ED and an SBIG STL-11000M
to make this picture.

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