Nebulas

Nebulas are high concentrations of interstellar gas and dust which slowly over time can coalesce into stars:

M20 (also known as the Trifid Nebula) is a star forming region located 5,200 light years away in the constellation of Sagittarius.

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The most easily viewed nebula is M42 located in the constellation of Orion. It can be seen easily by the naked eye as a small fuzzy patch in the sword region of the constellation but even modest magnification in binoculars or a small telescope reveals the sheer majesty of this object.

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A wide-field view of the lower half of the constellation Orion showing just how prominent M42 is in the winter sky.

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Other than M42 above, M8 is the only other nebula visible to the naked eye from northern latitudes. It is 5,000 light years distant and it is 110 x 50 light years in size.

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Gamma Cygni and a portion of the Gamma Cygni Nebula. Gamma Cygni (a mag 2.23 supergiant star) is actually in the foreground at 1,800 light years while the nebula itself is 3,000 light years distant. The nebula gets it crimson color from hydrogen alpha emission within the gas cloud.

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NGC 2078 is an example of a reflection nebula where the interstellar gas is illuminated by the surrounding stars. The reflection nebula is surrounded by lanes of dark nebulosity where the interstellar clouds are so dense that it blocks our view of background stars.

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Commonly referred to as “Hubble’s Variable Nebula” NGC 2261 is a small Reflection Nebula in the constellation of Monocerous. The gas and dust which makes up the nebula is illuminated by the variable star R Monocerous located at its base. The magnitude of R Mon varies from 11.0 to 13.8 with an irregular period which means that the brightness of the nebula likewise varies in-step with the brightness of the star.

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Zeta Orionis is the eastern star of Orions belt and is a binary double star. In the field-of-view we can see examples of hydrogen-alpha emission nebula, the emission nebula NGC 2024; and the refection nebula NGC 2023, all of which are surrounded by lanes of light-obscuring dark nebulosity.

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The iconic “Horsehead Nebula” lies just slightly south of the previous photo. As its name suggests a portion of the dark nebula resembles a horses head in silhouette. The nebula is composed of thick concentrations of interstellar dust and gas which blocks all the starlight behind it, while the red hydrogen-alpha emissions shining from behind provide a convenient backlight.

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The photo on the Left shows a portion of the Scutum Star Cloud – a dense star region near our galactic cneter. The photo on the Right show its position relative to the Milky Way as a whole. This portion of the Milky Way in the constellation of Scutum (The Shield) has few of the dense clouds of interstellar dust that block much of our view of the central portions of our home galaxy.

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