“The Snake Nebula” (Barnard 72) is our dark “S”-shaped friend just left of center and is located in the constellation Ophiuchus. Our snake’s neighboring inky splotches each has their own designation in the Barnard catalog (20th century astronomer E. E. Barnard’s catalog of 182 dark markings in the sky) and collectively they form a part of the much larger “Dark Horse Nebula,” which, to the naked eye under dark skies, takes on the appearance of a horse. These interstellar clouds of gas and dust obscure light from stars behind them, thus taking on this backlit appearance, as if resting atop a sea of stars. Relative to our vantage point on Earth, this view is looking toward the core of the Milky Way, hence the incredible density of stars.

What is particularly striking to me about these dark nebulae toward the heart of the Milky Way is their striking contrast with the density of stars at the heart of our galaxy—to me it almost looks like an undulating sea of stars—and I wanted to promote that in this image, so I went out of my way maintain and promote the light and glow of stars both resolved and too small to be resolved by my sensor, taking inspiration from the sort of light intensity you might see in a lovely, deep photography of the Milky Way.

Details: StellarVue SVX080T-35V with 0.8x reducer, ZWO ASI 2600MC Pro, Rainbow Astro RST-135E. 140x90s for about 3.5 hours of data. Calibrated with darks (optimized), flats, and bias. Edited in PixInsight and Adobe Photoshop. Photographed on July 21, 2023, high in the Uinta Mountains, Utah, United States.

Commentary: Accomplishing the above was a bit of a tricky task, and I did a lot of experimentation with this image. Editing is a little tricky in a distinct way as you want to capture the stars in one image and the background stars/glow in another, and it becomes a pretty intricate balancing act of preserving noise (as all those little stars are represented at the scale of noise) and color when re-blending. And the general light levels make it a bit more challenging to re-blend bright stars and promote star color. I’ve improved the process with another image I have captured, and was tempted to re-visit this edit to impart small-scale improvements, but rather than be obsessive, I have just decided to share. This photograph sure is a delight whenever it comes up on my photo frame.

Editing: Primarily in PixInsight. Some very mild high cloud interference on a subset of session; integrated best frames for a master and used Normalize Scale Gradients script to mitigate. No Light gradient removal. SPCC for color calibration. For stars image used StarX (correct stars only with no reduction and tiny boost to halos; some spherical aberration on reducer), mild noise reduction with NoiseX (luminance mask), stretched and nudged saturation with GHS, small adjustments to color calibration with GHS and levels, and further refinement to color balance and noise. For “background” image applied color calibration, mild noise reduction (NoiseX, luminance mask), and removed stars with StarX. Stretched with GHS, color adjustments, and cleaned up some odds & ends in Adobe Photoshop. Re-imported to PixInsight, and removed stars from stars image with StarX. Iterated on applying the stars to the background stars/glow image and undoing, adjusting stretch and colors using GHS, curves, levels, and masks, until I found a happy balance (including adjustments to the stars layer as color blending was tricky). Other than a small curves adjustment, stars weren’t reduced, as they are essentially the star (heh) of the image alongside the dark nebula. Exported to Photoshop for final adjustment, cropping.