This image shows one of my favorite nebulas, the Horsehead Nebula. My first couple of attempts weren’t that good, but I am very happy with these two versions.
The Horsehead Nebula is collocated with the Flame Nebula and the bright star Alnitak, the eastern most star in Orion’s Belt, as part of the Orion Molecular Cloud Complex. The are both located approximately 1,375 light years from Earth.The Horsehead Nebula is designated Barnard 33, and is the small dark nebula in the shape of a horsehead. The larger red cloud area is IC434 (Index Catalogue), which is a massive star forming Hydrogen Alpha region, hence the deep red hue, is behind the Horsehead nebula. Magnetic fields channel the gases, leaving the nebula into streams, shown as foreground streaks against the background glow. The visible dark nebula emerging from the gaseous complex, is an active site of the formation of "low-mass" stars. Bright spots in the Horsehead Nebula's base are young stars just in the process of forming.
The Flame Nebula (designated NGC2024 (New General Catalogue) and Sharpless 2-277) is an emission nebula, and large star-forming region. The nearby star Alnitak shines energetic Ultraviolet light into the Flame network, which frees electrons away from the surrounding great clouds of hydrogen gas. Much of the glow results when those electrons recombine with the ionized hydrogen. The dark network in the center of the nebula results from dark gas and dust that lies in front of the bright part of the nebula. High resolution images from the Hubble Space Telescope have observed the stars being formed behind the dust lanes.
Alnitak is a hot blue supergiant with an absolute magnitude of -6.0 and is the brightest class O star in the night star in the night sky with a visual magnitude of 2.0. (the lower the number the brighter the star).
There is a small emission nebula just below the Horsehead nebula (NGC2023), but I mistakenly thought it was an over exposed star and edited it out. The object is actually a small reflection nebula, radiating fluorescent molecular hydrogen emissions at a near-infrared range.There are two other identified objects in the image IC432 and IC435, are two other small reflection nebula that also got processed out thinking they were over-exposed stars.
Emission nebulae are nebula formed of ionized gases that emit light of various wavelengths. The most common source of ionization is high-energy ultraviolet photons emitted from a nearby hot star, and likely in this case, a high HII region (hydrogen gas), hence the typical deep red color in the photo, where star formation is likely taking place and young, massive stars are the source of the ionizing photons. Dark nebulae are so dense, that they obscure all visible wavelengths of light from being admitted. In astronomy, reflection nebula are clouds of interstellar dust which might reflect the light of a nearby star or stars. The energy from the nearby stars is insufficient to ionize the gas of the nebula to create an emission nebula, but is enough to give sufficient scattering to make the dust visible.
These pictures were shot with the ZWO Dual Narrowband filter which is great for heavy light pollution areas (like mine), bright moonlight, and allows light transmission in two main frequency regions:
1. Hydrogen Alpha (Ha) (red) at 656.3 nm with a bandwidth of 15nm
2. Oxygen III (Oiii) (blue) at 500.7 nm with a bandwidth of 35nm
This image was processed in two color formats – One shot color (which is dominated by the red spectrum) and the Foraxx color scheme. The Foraxx color scheme creates a blending of the Blue and Green channels of the RGB spectrum based on a combination of the brightest and darkest areas of the two channels. This often results in more “bronze-colour images, and was developed by “The Coldest Nights”, and I learned about it through many videos and the tools developed by Paulyman Astro.
These images that make up this picture were collected on October 28 and 29th, 2022. The moon was basically a waxing crescent near the first quarter (~15% light).
My setup:·
- Mount: EQ6R-Pro·
- Telescope: Williams Optics 81 mm Zenithstar doublet·
- ZWO-ASI224MC color camera for guiding with the Zenithstar guide·
- Hotech Corporation 2” Field Flattener·
- ZWO ASI2600MC Pro; Camera cooled to -10 deg C, with ZWO Duo-Band Narrowband Light Pollution Reduction Filter·
- Bortle-9 – South Los Angeles shot from my backyard·
- Integration Time: 4 Hours 30 Minutes; Lights (54 @ 300 seconds); Darks (30 @ 300 seconds); Flats (40) & Dark Flats (20) – Lights were captured on October 28th and 29th, 2022, with a Waxing Crescent moon (~15%))·
- Image Processing: Pixinsight – Using videos from multiple youtube teachers and website. @ChaoticNebula, @Cosgrove’sCosmos, @ViewintoSpace, @EnteringintoSpace, @PaulymanAstro, @Lukomatico – Lots of great on-line teachers/examples.·
- Incorporated Russell Croman’s new BlurXTerminator – Amazing product
#backyardastrophotography#highpointscientific#APOD#skyandtelescope#astrophotographer#williamsoptic#asiairplus#horseheadnebula#FlameNebulaHere is my simplified Pixinsight workflow that I have been tailoring over the last 4 to 5 months learning PixInsight and watching some really amazing people teach how the tools work.
1. WBPP with 2x drizzle (Including Cosmetic Correction) – Includes first dynamic crop
2. Perform a Linear Fit (with Green as a reference)
3. Extract a Luminance Image
4. Extract R, G, & B images
5. DBE 1st Div and 2nd Subtraction for both OCS and Luminance images
6. OCS Image – Linear Processing
a. Used Autocolor Script – Background Neutralization and Color Calibration
b. SpectroPhotometric Color Calibration (SPCC)
c. BlurXterminator – With star reduction of 0.2 and Halo -0.1
i. Used PSF Image script to find the best PSF diameter (plugged in manually)
d. StarXterminator – Generated Star Image and Upscreen Stars
e. NoiseXterminator – 90%
7. Foraxx Image Processing
a. For each of the R, G, & B images performed the following
i. BlurXterminator – With star reduction of 0.2 and Halo -0.1
1. Used PSF Image script to find the best PSF diameter (plugged in manually)
ii. StarXterminator – Generated Star Image and Upscreen Stars
iii. NoiseXterminator – 90%
8. Stretched with GHS Manual Script for R,G, & B
a. I then used Histogram_Transformation tool to get them all to the same background darkness
9. Non-Linear Flow – Foraxx Image
a. Used a range mask to isolate the nebula
i. Clone stamp to clean-up background artifacts (this is where I mistakenly cleaned up the reflective nebula)
b. Curves transformation to clean-up/darken the background
c. Inverted the mask to brighten the nebula (saturation and RGB increase)
d. Used Red and Yellow masks to isolate and adjust colors
e. Ran Foraxx Script to generate the Foraxx Image
f. Added Stars in with upscreen formula
g. Luminance Image created from Ha (Red image)
i. Used Local Histogram Equalization to add contrast
1. 20, 80, and 256 sizes with low limits of application (varying) and 1.5 contrast
ii. Additional Sharpening using Multiscale_Linear_Transformation (MLT)
iii. Added stars into Luminance image
h. Created Final Foraxx image with LRGB combination to apply luminance
i. Ran final Noise Xterminator to clean-up
10. Non-Linear Flow - OCS Image
a. Used Red and Yellow masks to adjust color and saturation
b. Used range mask from above to fix background
c. Performed LRGB combination with Luminance image from above
d. Decided to proceed without using the luminance layer
e. Exponential Transformation (w/ Mask) – Increase nebulosity brightness (just slightly)
f. Local Histogram Equalization (w/ Mask) – Basically increasing contrast
i. 20, 80, and 256 sizes with low limits of application (varying) and 1.5 contrast
g. Dark Structure Enhance Script
h. Noise Xterminator 90%
11. Stars (OCS)
a. Stretched with Histogram_Transformation to a smaller number of star that were appealing to my eye
b. Small Curves Transformation for Saturationc. Used a formula to put screened stars back (@PaulymanAstro)
12. Final Color adjustments (very minor)
13. Cropped pictures & Annotated with my signature
14. Output multiple picture types
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