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Sharpless 308 (the Dolphin Nebula) | by Martin_Heigan
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Sharpless 308 (the Dolphin Nebula)

A Narrowband HOO Palette image of the faint emission nebula Sharpless 308 (also cataloged as Sh2-308, RCW 11, and LBN 1052), or simply referred to as the Dolphin Nebula.


Sh2-308 is an emission nebula and HII region located near the center of the constellation Canis Major, composed of ionised Hydrogen. It is about 8 degrees south of Sirius, the brightest star in the night sky. The nebula is bubble-like, surrounding a Wolf-Rayet star named EZ Canis Majoris. This star is in the brief, pre-supernova phase of its stellar evolution.


About this image:

This image is the result of photographing over several nights from the Southern Hemisphere (from dark rural skies, to my Pier at home). Deep Sky Objects like this is a challenge, as it pushes the limits of my modest Telescope gear.


Technical Info:

24 x 600 sec. 7nm Hydrogen-Alpha (Ha).

24 x 600 sec. 6.5nm Doubly Ionized Oxygen (OIII).

William Optics Star 71mm f/4.9 Imaging APO Refractor.

Sensor cooled to -15°C on my QHY163M.

Calibration frames: Bias, Darks and Flats.

SGP Mosaic and Framing Wizard. ANSVR Solver via SGP.

Pre-Processing and Linear workflow in PixInsight,

and finished in Photoshop.


Astrometry Info:

Center RA, Dec: 103.602, -23.925

Center RA, hms: 06h 54m 24.409s

Center Dec, dms: -23° 55' 29.074"

Size: 1.48 x 1.11 deg

Radius: 0.925 deg

Pixel scale: 3.33 arcsec/pixel

Orientation: Up is 113 degrees E of N

View an Annotated Sky Chart for this image.

View this image in the WorldWideTelescope.


Nr. 1 in Flickr Explore:



Top 25 Photos on Flickr in 2019:


APOD GrAG on 2020/01/01:


The Art of Astrophotography:

Also visit my Flickr Group: The Art of Astrophotography, that features the work of Astrophotographers from around the world.


Martin Heigan


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Taken on January 30, 2019