Reflection and emission in SH2-311: The skull and crossbones nebula

Yet another image from telescope live. This was a super fun dataset to work with – even though the total integration time was only 6h 40min, the data was very clean and easy to play with. I decided to experiment with a way to separate broadband reflection and H-alpha emission using continuum subtraction only from LRGB data. Even though this method isn’t very “scientific,” it does an extremely good job of letting me enhance different parts of the nebulae. I haven’t seen many LRGB images of this area, so I wasn’t able to figure out if I should push the image more to reveal dust. If you move the slider in the image down below, you can see a starless image created by a neural network algorithm (starnet 2), which does a great job showing off the finer details.

This very colorful star-forming region seen in this new image of NGC 2467 taken from SSRO in Chile. Also known as the “Skull and Crossbones Nebula” is located in the constellation Puppis. Numerous stars and clusters come together to make this stunning stellar portrait.

One of the most notable clusters within NGC 2467, known as Haffner 18, houses around 50 stars—most are high-mass, but have already begun the transit into the celestial afterlife. They certainly help shape the pillars of gas and dust, but their role is negligible compared to that of HD 64315 located in the center of NGC 2467. This gargantuan star does most of the work. Its outbursts, ranging from flares, to coronal mass ejections and such, eject vast quantities of radiation into the nebular material, which has a carving effect. The dark splotches all around and in the nebula are Bok Globules. Within these regions, dust is packed together so tightly, light from embedded stars can’t break through.

Image:

Full quality image: https://live.staticflickr.com/65535/52736439394_4afb265153_o.png

Full quality starless image: https://live.staticflickr.com/65535/52736601070_8a0c9743be_o.png

Annotated Image

Full-quality image here:

Details:

Telescope: Planewave CDK24
Camera: FLI PL 9000
Filters: Astrodon LRGB 2GEN 
Location: El Sauce Observatory
Date of Observations: 1/31/2022, 3/3/2022, 10/29/2022, 11/1/2022 
L: 10 x 600s (1h 40min)
R: 10 x 600s (1h 40min)
G: 10 x 600s (1h 40min)
B: 10 x 600s (1h 40min)
Processing: Pixinsight
Credits: Data: Telescope Live; Processing: William Ostling

Processing:

Pre-processing and Stacking:
- Images were cosmetic corrected for hot pixels
- The subframes were weighted, registered, normalized, integrated, and drizzled in WBPP
Preparation of all frames:
- Stacking artifacts were cropped
- RGB Channels were combined to create an RGB image
- RGB image was plate solved
- Starless DBE was applied to L, RGB as follows:
      - Starnet 2 was applied to a clone of the target image, creating an image with stars and an image without stars
      - DBE was applied on the starless image to create a background model
      - The background model was subtracted from the stars image
- the RGB image was photometrically color calibrated and clipped H values were fixed with the repaired HSV separation script
Deconvolution of the luminance
- a PSF was created using the dynamic PSF process
- Linear starnet was applied to create a starless image and a star mask
- the linear image was duplicated, stretched, clipped, and convoluted to create a mask
- The starless image was deconvoluted using the RVC algorithm
- the stars were added back in
Noise Reduction:
- A low contrast mask was created and applied to the luminance image
- Noise Xterminator was applied with strength 73 and detail 0
- DeepSNR noise reduction was applied to RGB
Stretching Preparation:
- The L and RGB images were made starless using Starnet 2
Stretching:
- The Luminance image was stretched using HT and GHS
- The RGB image was stretched using ArcsinH and GHS
Non-linear adjustments
- Saturation adjustments on RGB
- LRGB combination
- HDR MST
- Saturation adjustments
- Extract Ha from image
- Create emissionless image and emission image
- Enhance blues in emissionless image and brighten emission image
- Addition
- Saturation adjustment
- MLT sharpening
- Stars are stretched and added
- Dark structure enhancement
- Star reduction
- slight non-linear reduction
- MMT sharpening