Image obtained February 26-27, 2017 through RVO's Explore Scientific’s 127mm ES127ED APO refractor with Explore Scientific’s .7 reducer/flattener lens resulting in an f/5.25 optical system -- using a Baader-modified Canon XSi DSLR and BackyardEOS image-acquisition software – 23 of 26 carefully selected and stacked 240-second RGB frames combined with multiple dark, flat and bias calibration frames shot at ISO 800 and totaling more than 240 minutes (92 minutes effective luminance) were used to create this image; optics driven by the Losmandy G-11 mount equipped with Ovision's precision RA worm gear, guided with a ZWO ASI 120MM Monochrome CCD camera through a 60mm guidescope using PhD2 guiding software and post-processed with DeepSkyStacker, CCDStack2 (DDP and deconvolution) and Photoshop CS3 s/w

Photographer's note: It is informative to compare this image above, taken with the superior Explore Scientific apochromatic refractor (3 optical elements, virtually no false color fringing) with my previous image of this very object, captured with a high quality but nevertheless a 2 optical element Williams' Optics Megrez achromatic refractor. The difference in the detail (especially noting the stars' lack of significant fringing coloration and general resolution) is extraordinary, due in part to the larger objective lens -- 127mm vs. 80mm -- but also due to the optical type (apochromatic vs. achromatic). Click this link for a discussion of telescopic lens optics.

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The bright star Alnitak (Zeta Orionis, the easternmost star in Orion's belt) is at the center of one of the most remarkable and picturesque regions in the sky.  The radiation of this hot star excites the gas in the surrounding nebulae and causes it to emit light.  The nebula strip running south (to the right and down in the photo) from Alnitak is the designated IC 434, into which the famous dark nebula called the Horsehead Nebula (Barnard 33) protrudes from the eastern side.  The dark nebula's shape resembles the head and neck of a horse, hence its name.  Dark nebulae are clouds of dust in space that obscure stars and other objects behind them.

The red nebula that delineates the Horsehead is known as Orion B, or NGC 2024. The blue nebula near center is NGC 2023; the purplish nebula left of Alnitak is IC 432.

Several dark lanes overlay it; the main one of these splits NGC 2024 into two parts.  This nebula certainly has a flame-like appearance.  Its western part is also overlaid by blue glare from the star Alnitak.  The unusual color of this nebula has been noticed, in color photographs it usually appears yellow or a sort of orange almost unique to this object.

To the left of the Horsehead the blue reflection nebula NGC 2023 is located.

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.

[information compiled from various internet sources]

 

[copyright Rabbit Valley Observatory/Willis Greiner, 2017 -- all rights reserved]