Orion’s Sword – Wide Field Dust and Reflections

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It’s been a little over ten months since I first started doing astrophotography. Back in the middle of February, 2014, I purchased an equatorial tracking mount, and imaged a few targets in the constellation Orion. My original attempts were fairly good, for a total beginner. I’ve long had aspirations, since before I ever started imaging myself, to go really, really deep…to bring out the details few people have the opportunity to see, to bring them a glimpse of true nature of the universe. I believe I’ve finally ended my journey as a beginner, and have now started my journey as a true astrophotographer with this wide field image of Orion’s Sword.

The image above is a wide field of view of the region around, and including, Orion Nebula, Running Man Nebula, all of the stars that make up Orion’s Sword, and the interstellar dust that permeates the region. This is an area of the sky about 3.4° x 2.3° in size. For reference, the moon is about 0.5° (thirty arcseconds) in size…so you could fit about 31 moons into the area of this image. In addition to the major nebula that make up the “fuzzies” in Orion’s Sword, a few additional faint reflection nebula can be seen as well. These include IC420, the blue reflection nebula near the upper left corner, IC428 a faint yellowish reflection nebula, and IC127 a buried blue reflection nebula, both just to the left of the bright reflection nebula IC1999, IC429 and IC430 to the left and above the bright star 49 Ori near the lower right corner, and a host of other small objects and fingers of dust that seem to have no official names or designations.

Orion's Sword Wide Field - Monochrome

Orion’s Sword Wide Field – Monochrome

All of this dust is part of the sheet of interstellar dust that flows off of the inner edge of Barnard’s Loop, a giant arc of hydrogen emission nebula that surrounds the left side of Orion. Most of the nebula within Orion, including Horsehead, Flame, and M78 nebulas, are also a part of this complex sheet of dust and gas that extends from Barnard’s Loop. This interstellar dust is nearly invisible to my camera when imaging from within the city, so I scouted out some “dark sites” a couple weeks back, and finally visited one on December 23rd…out at the end of East Quincy Avenue here in Colorado. The skies to the east and overhead measured 21.3 mag/sq” (magnitudes per square arcsecond). For reference, the darkest skies on earth are 22 mag/sq”, and for every increase in magnitude at dark skies, they get 2.5x darker. For further reference, my back yard is mag 17.5-18.3, or 17.9 mag/sq” on average. To get the image above, I had to find skies that were 8.5x darker than my back yard, and a mere 1.75x brighter than the darkest possible skies on earth (which are exceptionally rare, only a few locations on earth have skies that dark, limited by the glow from our atmosphere itself…airglow.)

Soon I hope to have additional images of these other objects, as well as some more obscure details within Orion, if the weather permits over the coming month or two.