The Cygnus Wall - NGC 7000 in Hubble and Visual Palettes
Observatory: The Conley Observatory at Comanche Springs Astronomy Campus (Three Rivers Foundation) near Crowell, Texas
Date: December 11 to 15, 2018
Telescope: 12" RCOS Ritchey-Chretien
Camera: FLI Proline PL-16803
Filters: Astrodon Spectral Band 3nm
Exposure Info: 15 x 20 minutes of H-alpha; 8 x 20 minutes of OIII; and 6 x 20 minutes of SII. All exposures are unbinned.
Total Exposure Time: 9 hours, 40 minutes
Date: December 11 to 15, 2018
Telescope: 12" RCOS Ritchey-Chretien
Camera: FLI Proline PL-16803
Filters: Astrodon Spectral Band 3nm
Exposure Info: 15 x 20 minutes of H-alpha; 8 x 20 minutes of OIII; and 6 x 20 minutes of SII. All exposures are unbinned.
Total Exposure Time: 9 hours, 40 minutes
About these images:
Here is the Cygnus Wall within the emission nebula, NGC 7000, the North America Nebula. What you see here is the “Mexican coast,” where north would be left in this orientation. The blue "water" would be the Gulf of Mexico. Emission nebula, like this complex, represent star forming regions, where hydrogen, among other gases, is available for new stars to be born. Hydrogen, oxygen, and sulfur glow in the dark at specific wavelengths, triggered by neighboring, hot young stars ”ionizing” the gases. These images are produced by taking images through specific filters to pass their narrow spectral bands to the sensor. Once collected, the individual channels can be mapped to traditional RGB color channels to produce a variety of color "palettes." The first image is the traditional "Hubble" Palette, made popular by the space telescope. It mixes SII to RED, H-Alpha to GREEN, and OIII to BLUE, all at 100%. Typically, the OIII (Oxygen) and SII (Sulfur) channels are, by far, the weakest of the data; therefore, they are typically much worse in signal/noise ratio. To produce a clean image, one can either image for multiple HOURS on the oxygen and sulfur OR they can simply use the H-Alpha (hydrogen) as the luminance component for the image. I did the latter, which makes this an Ha/SII/Ha/OIII image. The second image is a "visual" palette that attempts to make the image look as if it were taken through ordinary red, green, and blue filters. It's the most complicated of the three, using 75% hydrogen (H-Alpha) plus 25% sulfur (SII) for the RED channel, 100% oxygen (OIII) for the GREEN channel, and 80% OIII plus 20% H-Alpha for BLUE. My images would be considered "bold" by others who do this kind of work. It a critical point, actually...I feel that most people don't get much out of their spectral |
Am I getting better at this?I don't know what it is about this subject matter, but I've always used the North America and Pelican Nebula to monitor my progress through this hobby. While some people have the goal to image everything in the sky, I focus more of my atttention on improving my knowledge and skills in this challenging hobby. Above you can see a progression of images of the NGC 7000 and IC 5067 areas, and to make things even more interesting, I've taken at least this number of images that are NOT pictured above! Here are a few interesting items about each of the images: 2002 - Film image taken with Nikon F2 with 135mm lens, piggyback atop 10" Meade LX200 Classic; unguided. 2003 - Film image taken with Nikon F2 with 300mm lens, piggyback atop 10" Meade LX200 Classic; guided prime focus with Meade 208XT autoguider. 2005 - Taken with SBIG STL-6303E with Tak FSQ-106 apo refractor and Tak NJP mount; this HaRGB image won the Best Deep Sky Photograph at the Texas Star Party. 2006 - Using h-alpha data from the previous image, I added OIII and SII to create a Hubble palette version. 2006 (#2) - An HaRGB image using FSQ-106, SBIG STL-11000, and Paramount ME...shot from Okie-Tex Star Party. 2018 - I came back to this object using a Nikon D810A and Tak FSQ-85 with Tak NJP mount; unguided. 2018 (#2) - The grayscale h-alpha presentation of the same data used above on the Cygnus Wall. |
band data, choosing to allow only two or three hues to represent everything rather than to work toward mixing them together for a wider color "palette." For example, while Hubble palette images are pretty, most images produced by amateurs eschew the green color (h-alpha) almost complete, leaving behind limited shades of blue and yellow. Certainly, you can produce beautiful images without allowing the colors to completely mix, but it becomes rather predictable, in my opinion. Here, the colors blend quite well to form a rainbow of fruit colors, including reds, purples, and greens not typically seen in spectral band images. 🙂
This image set was taken December 11 to 15, at the Conley Observatory on the Comanche Springs Astronomy Campus near Crowell, Texas. Captured remotely from my home, 222 miles away.
All sub-exposures are 20 minutes unbinned, with 300 minutes of Hydrogen-Alpha, 160 minutes of Oxygen-III, and 120 minutes of Sulfur-II...TOTAL EXPOSURE TIME is 9 hours and 40 minutes. Processed in PixInsight and Photoshop CS6.
The atmospheric “seeing” was exceptional, though the optics are suffering from some critical alignment issues. This image should be sharper.
This image set was taken December 11 to 15, at the Conley Observatory on the Comanche Springs Astronomy Campus near Crowell, Texas. Captured remotely from my home, 222 miles away.
All sub-exposures are 20 minutes unbinned, with 300 minutes of Hydrogen-Alpha, 160 minutes of Oxygen-III, and 120 minutes of Sulfur-II...TOTAL EXPOSURE TIME is 9 hours and 40 minutes. Processed in PixInsight and Photoshop CS6.
The atmospheric “seeing” was exceptional, though the optics are suffering from some critical alignment issues. This image should be sharper.