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Cosmic Challenge: Sharpless 2-301


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Cosmic Challenge:

Sharpless 2-301

 

February 2019

 

Phil Harrington

 

This month's suggested aperture range

10- to 14-inch (25-36cm) telescopes

 

Target

Type

RA

DEC

Constellation

Mag

Size

Sharpless 2-301

Emission
nebula

07 09.8

-18 29.8

Canis Major

--

9'x8'

 

The 1950s was a banner decade for deep-sky catalogs.  Not only did it give us such seminal works as the Abell catalogs of galaxy clusters and planetary nebulae, the decade also closed with the release of the second edition of Stewart Sharpless's famous catalog of emission nebulae.  Sharpless had assembled his collection of objects from his research at the United States Naval Observatory's Flagstaff Station in Arizona.  The "Sharpless 2" catalog, a revised version of a list he first published in 1953 while at Mount Wilson Observatory, lists 313 emission nebulae (Hydrogen-II regions, as Sharpless preferred to call them) that are among the most spectacular photographic sights that the Milky Way has to offer.

 

Above: Winter star map. Credit: Map adapted from Star Watch by Phil Harrington

 

 

Above: Finder chart for this month's Cosmic Challenge.

Credit: Chart adapted from Cosmic Challenge by Phil Harrington
Click on the chart to open a printable PDF version in a new window

While a few of Sharpless's entries, such as Sh2-25 (better known as M8, the Lagoon Nebula) and Sh2-49 (M16, the Eagle Nebula), are well known to visual observers, most are among of the most challenging objects to see visually.

If you have never made a concerted effort to see some of the lesser known Sharpless objects, then this challenge, Sh2-301 in Canis Major, is a good introduction to the sport.  You will find it about 6° east-southeast of Sirius [Alpha (α) Canis Majoris], within a diamond of six 6th- to 8th-magnitude stars. Approximately 42,000 light years lie between it and our telescopes.

Unlike many of the Sharpless objects, which can cover swaths of sky larger than the fields of many telescopes, Sh2-301 measures just 9'x8' across.  That's small enough to fit easily into a single eyepiece field, yet is still large enough to be apparent if you are aimed in the right direction.  My best view with my 10-inch (25cm) comes at 58x, with a 22mm eyepiece and a narrowband (UHC-style) filter in place.  Without a filter, the nebula is difficult to see, even from a dark site.  With a filter in place, however, hints of the cloud may be glimpsed from suburban settings as long as light pollution is minimal toward the south.

From dark-sky sites, Sh2-301 reveals an unusual shape that is best described as an irregular, three-lobed fog with thin lanes of dark nebulosity threaded throughout.  Several stars appear superimposed on the nebula.  The brightest is a 10th-magnitude point found toward the cloud's southeastern edge.  Another tuft of brighter nebulosity appears to surround a triangle of 12th-magnitude stars at the northern border.  These stars make a handy gauge for judging the full extent of the nebula.

Here are two renderings of Sh2-301 from members of the CN Sketching forum.

Above left: Sh2-301 sketched by CN member Sheliak_sp through a 12-inch (30.5cm) scope.

Above right: Sketch by member Raul Leon using a 14.5-inch (36.6cm) scope.


Post your own observations and sketches in this article's discussion forum.  I'd be especially interested in hearing from those who spot Sh2-301 in smaller apertures!

Have a favorite challenge object of your own?  I'd love to hear about it, as well as how you did with this month's test.  Contact me through my web site or post to this month's discussion forum.

Until next month, remember that half of the fun is the thrill of the chase.  Game on!



About the Author:

Phil Harrington writes the monthly Binocular Universe column in Astronomy magazine and is the author of 9 books on astronomy.  Visit his web site at www.philharrington.net to learn more.

Phil Harrington's Cosmic Challenge is copyright 2019 by Philip S. Harrington.  All rights reserved.  No reproduction, in whole or in part, beyond single copies for use by an individual, is permitted without written permission of the copyright holder.

 


  • Achernar, okiestarman56, John O'Hara and 2 others like this


4 Comments

Photo
Astrojensen
Feb 01 2019 03:33 PM

Uh - this one's getting a little low for me. Still going to give it a go, though.

 

 

Clear skies!
Thomas, Denmark

    • PhilH likes this
Photo
micromaxcomputer
Feb 11 2019 04:12 PM

Thanks for sending me on this challenge! I wheeled out my 12" Meade LX200 classic with an Orion ED80 on top, added this as a user object put in the RA and DEC and gave it a shot. Using a ZWO ASI174MC camera with a 0.7 focal reducer and Astronimik CCD CLS filer I was disappointed to not see anything unusual on my laptop screen with 90 sec exposures and gain at 270. so I only took about 20 exposures and moved on to something that I thought would be more rewarding. And since I live under Bortle 8 skies (North East New Jersey, only 16 mile to Times Square) I figured this elusive challenge object was a bust. But once I processed my images (only in DSS) and this nebulosity appeared in front of my eyes I was truly amazed. So thank you as being able to see this in the sky glow on New York City give my passion a little more excitement.

Sh2 301
    • PhilH and hokkaido53 like this

Thanks for sending me on this challenge! I wheeled out my 12" Meade LX200 classic with an Orion ED80 on top, added this as a user object put in the RA and DEC and gave it a shot. Using a ZWO ASI174MC camera with a 0.7 focal reducer and Astronimik CCD CLS filer I was disappointed to not see anything unusual on my laptop screen with 90 sec exposures and gain at 270. so I only took about 20 exposures and moved on to something that I thought would be more rewarding. And since I live under Bortle 8 skies (North East New Jersey, only 16 mile to Times Square) I figured this elusive challenge object was a bust. But once I processed my images (only in DSS) and this nebulosity appeared in front of my eyes I was truly amazed. So thank you as being able to see this in the sky glow on New York City give my passion a little more excitement.

Amazing what can be done thanks to the magic of post-processing, isn't it?  Nice capture!

    • hokkaido53 and micromaxcomputer like this
Sh 2 301 Emission Nebula in Puppis


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