The Hourglass Nebula in Messier 8


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Observation Notes:

Deep in the bright heart of the Lagoon Nebula lies a knot of fluorescing gas called the Hourglass Nebula. While observing at Kitt Peak Observatory’s Advanced Observer’s Program with four good friends, I enjoyed a couple minutes boring into the Lagoon with the 16-inch Ritchey-Chretien. This bright flare was indeed shaped like an hourglass resting on a bed of wrinkled fabric. A bisection occurred where the two halves of the hourglass met, and the western side was bordered by a tri-lobed patch of dark nebulosity. I did not want to hog the eyepiece too long, so I worked up a quick contour sketch of the area and applied shading after returning home. The structure was distinct enough, that I think I should be able to observe it with my 6 or 8 inch scopes–I just hadn’t tried before.

My overall M8 observation report and sketches can be found here: M8.

Object Information:

The blazing gases in the Hourglass Nebula are primarily lit by the star Herchel 36, which can be seen in the sketch (nestled in the dark nebulosity to the west of the hourglass). A close-up look with the Hubble Space Telescope shows that the bisection of the hourglass shape is caused by vortices of dust and gas. It is possible that strong temperature gradients and stellar winds could create shearing forces that sculpt the tornadic shapes. However, future observations will be needed to determine velocities and see if this is indeed what is happening.

Subject Hourglass Nebula (M8)
Classification Emission Nebula
Position* Sagittarius [RA: 18:03:41.2 / Dec: -24:22:49]
Size*
Brightness*
Date/Time June 9, 2008 – 1:00 AM MST (June 9, 2008 – 08:00 UT)
Observing Loc. Kitt Peak Observatory, Arizona
Instrument 16″ Ritchey-Chretien (f/8.4)
Eyepieces/Mag. 17 mm Nagler + 2X Barlow (400X)
Conditions Clear, calm
Seeing 7/10 Pickering
Transparency ~ Mag 7.0 NELM
*References SEDS

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