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Astronomical Observatory: Cool Images

Astr110 Photography Projects, Fall 2006

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Hourglass Nebula (M8) , Stacy Maat

Hourglass Nebula

This amazing picture was taken on June 6, 2006 in the constellation of Sagittarius. This picture is of the Hourglass Nebula, a smaller part of a much larger nebula the Lagoon Nebula. The distance from us is about 5,200 light years away.To the left of the image an open cluster of stars is seen. This cluster of stars is cataloged as NGC 6530 and is believed to be situated just in front of the nebula seen in the photograph. This cluster was apparently first observed by Hodierna before 1654, and later officially cataloged in 1680. The open cluster has anywhere from 50 to 100 stars varying in brightness and magnitude. The brightest star in the cluster is believed to be over 2,000,000 years old, therefore the rest of the stars are about the same age. The brighter right side of the picture is the Hourglass Nebula, which is a part of the Lagoon Nebula. The Hourglass Nebula was discovered by John Herschel in 1847. He described the Nebula as:

"A collection of nebulous folds and matter surrounding and including a number of dark, oval vacancies and, in one place, coming to so great degree of brightness as to offer the appearance of an elongated nucleus. Superimposed upon this nebula and extending in one direction beyond its area, is a fine and rich cluster of scattered stars which seems to have no connection with it as the nebula does not, as in the region of Orion, show any tendency to congregate about the stars."

Scattered throughout the photograph, there are points in the picture that look as if they are mistakes, or smudges on the telescope...the very dark splotches among the gas are in fact globulars of dust which are in our frame of view...blocking our view of the nebula. The fainter, redder stars are either cooler in temperature, or are blocked by the dust particles in front of them. From this picture it is hard to tell which is the case. If the picture was somewhat larger, we may be able to see if the nearby stars are brighter, if they are...the stars in this picture are blocked by the dust, if they are not brighter but in fact the same in magnitude, the stars are cooler stars. This nebula, like most others, is a combination of glowing background gas and beautiful and amazing intricate wisps and lanes of dust that give the nebula its name. In this picture you can see the pinker areas of the picture against the background of the sky...the pinker areas are the gases and dust and you can see some very thin lanes of where there is no gas near the area of the hourglass. The Hourglass Nebula occurs in a region where a vivid star formation process appears to take place currently; the bright emission is caused by heavy excitation of very hot, young stars.

The beautiful open cluster of stars are a result of being located near a stellar nursery.

The object itself is much larger than our field of view in the telescope. The view in our telescope is 14 arc minutes by 21 arc minutes, resulting in an image that is approximately 1270 light years in size...only a portion of the entire object.

Frommert, Hartmut, and Christine Kronberg. "Lagoon Nebula." Messier 8. 25 Jan. 2006. SEDS. 13 Nov. 2006 <>.

Frommert, Hartmut, and Christine Kronberg. "Messier 8 Observations and Descriptions." Messier 8. 5 Feb. 2005. SEDS. 14 Nov. 2006 <>.

Frommert, Hartmut, and Christine Kronberg. "Star Clusters." Students for the Exploration and Development of Space. 21 Nov. 1999. SEDS. 14 Nov. 2006.

Nemiroff, Robert, and Jerry Bonnell. "M8, the Lagoon Nebula." Astronomy Picture of the Day. 10 Feb. 2006. NASA. 13 Nov. 2006.


Right Ascension (J2000) 18:04:14
Declination (J2000) -24:16:41
Filters used blue(B), green(V), and red(R)
Exposure time per filter

26 exp. 15 sec in Blue filter

14 exp. 15 sec in Green filter

13 exp. 15 sec in Red filter

Date observed

June 6, 2006




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