Hemisphere:  Southern  ·  Constellation: Canis Major (CMa)  ·  Contains:  The star ο1CMa
Getting plate-solving status, please wait...
Dolphin Head Nebula (Sh2 308), 


            Ryan Haveson

Dolphin Head Nebula (Sh2 308)

Getting plate-solving status, please wait...
Dolphin Head Nebula (Sh2 308), 


            Ryan Haveson

Dolphin Head Nebula (Sh2 308)

Technical card

Imaging telescopes or lenses: William Optics FLT 132

Imaging cameras: ZWO ASI294MM-Pro

Mounts: iOptron CEM 70

Guiding telescopes or lenses: William Optics 50mm Guidescope

Guiding cameras: ZWO ASI174mm Mini

Focal reducers: William Optics Reducer Flattener 68III

Software: PixInsight  ·  NINA

Filters: Astrodon 36mm Filter Set (3nm Sii/Oiii, 5nm Ha)  ·  Baader Planetarium LRGB 36mm

Dates:Jan. 1, 2021

Frames: 300x300"

Integration: 25.0 hours

Avg. Moon age: 17.06 days

Avg. Moon phase: 94.14%

Basic astrometry details

Astrometry.net job: 4159818

RA center: 6h 54' 8"

DEC center: -23° 44' 49"

Pixel scale: 1.431 arcsec/pixel

Orientation: 125.104 degrees

Field radius: 0.936 degrees

Resolution: 3936x2582

Data source: Backyard


This was taken in my back yard (Bortle 8/9) over the course of a couple weeks. A very challenging target because the signal is very dim and the object is low in the sky so I could only get a few hours a night on it.

- 165 x 60s each in R, G, B ( 8.25h )
- 137 x 300s Ha ( 11.4h )
- 159 x 300s Oiii (13.25h )

This was also the first target with my new WO FLT 132, new mount (iOptron CEM 70), new focuser, new guide scope, and new filters. So a spent a good bit of time trying to get things dialed in.

From Wikipedia:

Sh2-308, also designated as Sharpless 308, RCW 11, or LBN 1052,[1] is an H II region located near the center of the constellation Canis Major, composed of ionised hydrogen.[2] It is about 8 degrees south of Sirius, the brightest star in the night sky. The nebula is bubble-like (hence its common name, the Cosmic Bubble), surrounding a Wolf–Rayet star named EZ Canis Majoris. This star is in the brief, pre-supernova phase of its stellar evolution. The nebula is about 4,530 light-years (1,389 parsecs) away from Earth,[3] but some sources indicate that both the star and the nebula are up to 5,870 ly (1,800 pc) away.[4][5] Yet others indicate the nebula is as close as 1,875 ly (575 pc) from Earth.[6]

The nebula was formed about 70,000 years ago by the star EZ Canis Majoris throwing off its outer hydrogen layers, revealing inner layers of heavier elements.[2] Fast stellar winds, blowing at 1,700 km/s (3.8 million mph) from this star, create the bubble-shaped nebula as they sweep up slower moving material from an earlier phase of the star's evolution. The hydrogen composing the nebula is ionised by intense ultraviolet radiation.[9] The nebula is approximately 60 light-years across at its widest point.[10]


Sky plot

Sky plot


Dolphin Head Nebula (Sh2 308), 


            Ryan Haveson