Hemisphere:  Southern  ·  Constellation: Canis Major (CMa)  ·  Contains:  16 omi01 CMa  ·  LBN 1047  ·  LBN 1052  ·  Sh2-303  ·  Sh2-308  ·  The star ο1CMa
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Dolphin Head Nebula SH2-308, 



    
        

            Linwood Ferguson
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Dolphin Head Nebula SH2-308

Getting plate-solving status, please wait...
Dolphin Head Nebula SH2-308, 



    
        

            Linwood Ferguson
Powered byPixInsight

Dolphin Head Nebula SH2-308

Acquisition details

Dates:
Jan. 31, 2022
Frames:
Chroma H-alpha 5nm Bandpass: 170×300(14h 10′) (gain: 100.00) -10°C bin 1×1
Chroma OIII 5nm Bandpass: 260×300(21h 40′) (gain: 100.00) -10°C bin 1×1
Integration:
35h 50′
Avg. Moon age:
28.71 days
Avg. Moon phase:
0.77%
Bortle Dark-Sky Scale:
6.00

RA center: 06h54m08s.28

DEC center: -23°2844.3

Pixel scale: 1.397 arcsec/pixel

Orientation: -87.743 degrees

Field radius: 1.500 degrees

WCS transformation: thin plate spline

More info:Open 

Resolution: 6418x4279

File size: 8.4 MB

Locations: Home, Fort Myers, Florida, United States

Data source: Backyard

Description

The Dolphin Nebula has name of "Sharpeless" 2-308.  With a little imagination "Dolphin" or "Dolphin Head" is much more descriptive.  

It is about 5200 light years away in Canis Major, and almost twice the width of the full moon. 

Here it is shown in Ha and Oiii (most of the head is Oiii).  The nebula is created by the star near the center of the head (not the brightest one at the edge).  This is only Oiii and Ha; I also took a few Sii but there was no visible structures at that wavelength.  

The image was created with R=Ha, G=(Ha*2 + Oiii)/3, B=Oiii.  I worked quite a bit to de-emphasize the surrounding stars, reducing their size in the synthetic luminance (from Ha + Oiii) before the Luminance combine, but even afterwards I applied a slight gaussian blur to make the tiny stars less prominent.

The image was taken over 8 nights from 1/15/2022 thru 1/31/2022, and I thank John Murphy's Normalize Scale Gradient that I was able to salvage some of the Oiii that I took with much too much moonlight.

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