Sharpless 2-301 in Canis Major

[stevecoe]

Howdy all;

Because it is in such good position for this New Moon, I will post about a favorite of mine. Sh 2-301 is an emission nebula in the Canis Major Milky way.

Here is an observation with a 13 inch f/5.6 newtonian:

Sharpless 2-301 Pretty bright, pretty large, irregular shape at 100X on a night I rated 8/10 for seeing and transparency in the mountains of central Arizona. My first observation of this object was from a somewhat light polluted site and I called it faint, it is much better from a dark site. All these observations are with the UHC filter, it helps a lot on this object. This nebula has a three branch structure with many stars involved. There are a few detached sections of nebulosity that are out of the 30 minute field. This is an unmarked box on the Tirion Sky Atlas.

This observation is with a 6 inch f/8 refractor:

Sh2-301 Antennas site, about 100 miles from Phoenix 6" f/8 refractor S=7, T=8 14mm EP very faint, pretty large, round, 5 stars involved. Adding UHC filter gives pretty bright, large, very irregular figure with 4 stars involved. The "3 branch" outline is displayed with averted vision and the filter. The number of stars seen with averted vision is 11 stars involved, but the last 6 or so are very faint.

This drawing was with a 17.5 inch at 100X with a UHC filter.

CMA_Sharpless 301_17in_100X_UHC.jpg

Clear skies;
Steve Coe

[reiner]

Hi Steve,

Sharpless 301 is also a favorite of mine, together with Sharpless 308 and 311 in the same area. My notes are:

Sharpless 301 is an untypical Sharpless objects due to its unusually high surface brightness. It is astonishing that it was not discovered by the observers of the NGC and IC era. Sharpless 301 responds well to both OIII and UHC filtering. With filter, it is well visible with my 8" Dob as a small nebulous patch with a row of three bright stars superimposed. With my 22" Dob, the object appears highly structured in front of the Milky Way background. From NE, two dark bays are protruding into the emission nebula. The western of this protrusions cuts through the entire nebula and divides it into two unequal E and W parts. The E part appears to have a quite well defined shape with sharp boundaries, pointing to the presence of another dark nebula. The W part is much less well defined. Despite that the nebula appears better defined with OIII filter as compared with UHC, the object is more pleasing to me with UHC as the superimposed stars are not that much suppressed.

[Steve Gottlieb]

Here's another big fan of Sharpless 301! But although it's definitely one of the best Sharpless regions missing from the NGC, it's only transformed into a showpiece with an OIII or narrow-bandpass filter. Without a filter, I'm not that surprised it was missed considering there are no other NGC's nearby.

[stevecoe]

Hi Steve, Reiner, et al;

I agree with the idea that discovering this object without a filter would have been difficult, the UHC certainly makes a big difference. I like that so much detail can be seen in a modest telescope on a good night.

Lots of fun;
Steve Coe