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Sh308 The Gourd Nebula in Canis Major

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By
Catalog
Obj Type
Location
Date Taken:
Don Goldman
Sharpless 308
Nebula
RDO Observatory, Moorook, S. Australia
04-01-2009
Description

NASA Astronomical Picture of the Day (APOD)  April 23, 2009

Sharpless 2_308 (RCW 11) is a large, faint ring nebula surrounding a Wolf-Rayet star (WR 6) EZ CMa (6hr 54m 36s, -23deg 56m 36s) in Canis Major .I'm using the "Gourd Nebula" because of its shape with the projections at the upper left.  It reminds one of a Florence Glass Flask or Round Bottom Flask in a chemistry laboratory.

WR6 is the bright, blue star near the center of the image and has been the subject of considerable research.  The large yellow star is Omicron 1 CM.   The nebula has an age of 70,000 years and an expansion velocity of 60 km/s.  It is one of the closest WR stars to our solar system.  The bubble is large, taking up nearly 3/4 deg in this image, and is the result of fast WR winds sweeping through slower red supergiant winds.  The [OIII] signal dominates this structure, whereas the H-a signal is comparably much weaker.  Although the object is roughly circular, there is a strange set of projections toward the upper left (North is toward the left).

This image was taken with Astrodon 3 nm OIII and 5 nm H-a filters. Star colors were taken with Astrodon Generation 2 RGB filters and blended in.  Narrowband colors are mapped to Red = H-a, Green = Blue = OIII.  Data were acquired with CCDAutoPilot4 running Maxim4.62 and PinPoint5 for image linking. Guiding was done with an SBIG ST-402 on an Astrodon MonsterMOAG.

I would like to thank Dean Salman for encouraging me to take a high-resolution image of this object.

 




 
Technical Details
Exposure Time:
2.67 hrs H-a, 3 hrs OIII, 0.5 hrs RGB
Camera:
Apogee U16M
Telescope:
RC Optical 14.5" f/8.2 Classical Cassegrain
Mount:
Software Bisque Paramount ME
© 2010 Don Goldman
Used with permission, No reproduction of these images are permitted without written approval from Don Goldman.