Seeking Dark Nebulae

[scarp15]

Dark Nebulae: molecular star forming clouds of dark dust blocking the light from background stars, can be a challenge to the visual observer. Yet a few are attainable by naked eye, binoculars or a rich field telescope. Originally catalogued by E.E Barnard in his Catalogue of Dark Markings in the Sky, the summer season probably contains many of these more notable targets. However the winter period can also be a good time to try and observe some of these more visually elusive objects, exploring beyond  just the iconic B33; Horse Head Nebula.

Here are some of my own highlights, throughout the observing season, during nights of transparent, dark sky observing.

The very first and one of the easiest to locate and see is B168, The Dark Cigar, that is situated high up in Cygnus and drifts towards the visually subtle challenge of the Cocoon Nebula. Even with a H-beta filter attached (for the Cocoon), this long nebula stands out and is quite visible in binoculars.  

The next dark nebula to command my attention and as with many visual astronomers, was B33 the Horse Head Nebula. Considered a difficult object that (regardless for there being little to actually see) seasonally engages fascination, the 'notch' of B33 will leap out if employing averted vision with a moderate aperture scope. Each encounter, that is two or three times a year, I get to grasp a little more of its characteristic profile, quite enticing. 

My attention next turned to what is considered to be perhaps another of the easiest and defined in form, the dark markings that constitute for B142 and B143, notably referred to as Barnard's E. Located in Aquila not too far from Gamma Aquila, The position is straight forward to locate yet can initially become a challenge. Transparency needs to be good and they are particularly suited to rich field and binocular observing. Not unlike the Horse Head, it took a few times with different instruments and under different circumstances before I finally got this object. It is one to keep trying for, as once seen will become easier to accomplish, perhaps the etched E, a nod to Mr Barnard.   

Last year I went in pursuit of B144, embedded in the Cygnus Star Cloud, this large object requires a wide field to appreciate. Commonly known as The Fish on a Platter, I captured this during the summer on a wild camping trip. Roaming through Cygnus with my 16x70 binoculars, stretching the 4.1 degree field, a larger object than my perceived field of view, yet quite shapely none the less.   

There are more besides that I would have simply looked through and others I have tried to pursue but have not so far comprehended or succeeded. A return this winter will be for B34 in Auriga and close to the Open Cluster M37 and of a similar scale, considered to be fairly straight forward. There is a good sketch and description for B34 on the Belt of Venus, Jeremy Perez web site. There are also others that lie in Perseus, Cepheus, Taurus and Orion that I would like to go back to or attempt, each with varying degrees of difficulty. Barnard 160 in Cepheus, aligned near to IC 1396, the Elephant Trunk Nebula is another feasible target. 

I am also interested in looking for B5 in Perseus but considered to be more of a challenge. 

Do you have experiences for observing dark nebulae, such as the ones mentioned or some of the other notable Barnard objects as B92 and B93 near M24 in Sagittarius?

Edited February 7, 2020 by scarp15

[Ships and Stars]

The dark cigar is striking simply due to the sheer absence of any stars in contrast to its immediate surroundings. That's more interesting to me than the Cocoon itself I suppose. The other ones you mention are intriguing, will definitely add any to the list I can manage. How do you use filters on your binoculars? One UHC and one OIII, or one Hb and no filter on the other side? Great post by the way!

[Littleguy80]

Excellent post, Iain. I particularly enjoyed Barnard 86 (Ink spot nebula) in Sagittarius. It’s next to the open cluster NGC 6520. A tricky one for UK observers due to being quite low. A nice target if you can get on it though. B92 and B93 are both great targets.

E.E. Barnard’s original photographic plates can be viewed online here:

https://exhibit-archive.library.gatech.edu/barnard/

I have a copy of his book “A photographic atlas of selected regions of the Milky Way” which is an excellent resource. 

[Mark at Beaufort]

Excellent thread Iain - if I ever get a clear spell I will go hunting.

[PeterW]

Good to know the “easy ones” to go for. I think I just snagged the a E, took a lot of failed attempts.

 

peter

[John]

Interesting report - thanks for posting it

I've seen B33 / The Horsehead a couple of times now but it needs a really good night here to get it and we have not had one for some time now

I must have a go at some of the others you mention when next out under a darkish sky with my dob.

We had an interesting talk at my society about Dark Nebulae last year from Owen Brazell. I was going to ask this question then but forgot so I'll ask it here if that's OK - does the dark rift in the Orion Nebula known popularly as "The Fishes Mouth" count as a dark nebulae or is it more an absence of bright nebulosity in that region ?

[scarp15]

4 hours ago, Ships and Stars said:

The dark cigar is striking simply due to the sheer absence of any stars in contrast to its immediate surroundings. That's more interesting to me than the Cocoon itself I suppose. The other ones you mention are intriguing, will definitely add any to the list I can manage. How do you use filters on your binoculars? One UHC and one OIII, or one Hb and no filter on the other side? Great post by the way!

Hi Robert, thanks, the binoculars I use are not threaded for filters. It could be possible to try holding a 2" filter to an objective lens, but I don't know how practical this will turn out to be, not much perhaps. With the exception of B33, the dark nebulae mentioned do not as far I am aware require filtered assistance. The Dark Cigar is certainly more interesting than the reflection / emission nebula it appears to feed into. 

 

2 hours ago, Littleguy80 said:

Excellent post, Iain. I particularly enjoyed Barnard 86 (Ink spot nebula) in Sagittarius. It’s next to the open cluster NGC 6520. A tricky one for UK observers due to being quite low. A nice target if you can get on it though. B92 and B93 are both great targets.

E.E. Barnard’s original photographic plates can be viewed online here:

https://exhibit-archive.library.gatech.edu/barnard/

I have a copy of his book “A photographic atlas of selected regions of the Milky Way” which is an excellent resource. 

Thanks Neil and that is very interesting concerning your observation for B86.  E.E. Barnard described this nebula as 'a remarkable small inky black hole in a crowded part of the Milky Way'. Lying within Sagittarius it is a bit tricky from my latitude but could be something to have a go at next summer, thanks for the mention of this and comment on B92, B93 and yes that is a good resource.

 

2 hours ago, Mark at Beaufort said:

Excellent thread Iain - if I ever get a clear spell I will go hunting.

Cheers Mark, good luck with that. You can almost throw everything at these objects, binoculars, wide field refractor, medium sized dobs and in Gerry's case when he steps in, just looking up from a recliner, at least upon certain subjects in Cygnus. 

 

2 hours ago, PeterW said:

Good to know the “easy ones” to go for. I think I just snagged the a E, took a lot of failed attempts.

 

peter

Congrats on that Peter. It took a couple attempts, first with an 8" f6 dob, later the refractor and binoculars worked and I will return to using the dob in late summer. It is a particularly interesting subject to attempt to observe and examine when you have grasped it.  

 

48 minutes ago, John said:

Interesting report - thanks for posting it

I've seen B33 / The Horsehead a couple of times now but it needs a really good night here to get it and we have not had one for some time now

I must have a go at some of the others you mention when next out under a darkish sky with my dob.

We had an interesting talk at my society about Dark Nebulae last year from Owen Brazell. I was going to ask this question then but forgot so I'll ask it here if that's OK - does the dark rift in the Orion Nebula known popularly as "The Fishes Mouth" count as a dark nebulae or is it more an absence of bright nebulosity in that region ?

Definitely worth a try with the dob John. Yes that talk must have been very interesting. The Fish Mouth as far as I understand is a dark intrusion,  it would however be interesting to hear of any other thoughts on this.

 

[John]

19 minutes ago, scarp15 said:

..... The Fish Mouth as far as I understand is a dark intrusion,  it would however be interesting to hear of any other thoughts on this.

 

This Sky & Telescope article from 2014 refers to "The Fishes Mouth" as being dark nebulosity but whether that is the same or similar to the nature of the targets that you describe I'm not sure

https://www.skyandtelescope.com/observing/see-orion-nebula-3d12172014/

 

[scarp15]

That is an insightful article John thanks for posting. The Fishes Mouth area is I think composed of the same emission, reflection nebula composition, yet appears as a silhouette. I am also not certain whether it is defined as of the same nature?  Interstellar dust from a dark nebula, absorbs visible wavelengths of stars and emission, reflection nebula. This may or may not constitute for the Fishes Mouth, would be interesting to learn more about the science. The nature of the largest dark nebulae that appear in the Milky Way as naked eye objects such as the Great Rift, are irregular patches in character and referred to as dark cloud constellations.

Not much more insightful but here is another article.

https://astrobob.areavoices.com/2018/12/28/behold-the-orion-nebula-winters-most-beautiful-flower/

 

 

Edited February 8, 2020 by scarp15

[John]

6 hours ago, scarp15 said:

That is an insightful article John thanks for posting. The Fishes Mouth area is I think composed of the same emission, reflection nebula composition, yet appears as a silhouette. I am also not certain whether it is defined as of the same nature?  Interstellar dust from a dark nebula, absorbs visible wavelengths of stars and emission, reflection nebula. This may or may not constitute for the Fishes Mouth, would be interesting to learn more about the science. The nature of the largest dark nebulae that appear in the Milky Way as naked eye objects such as the Great Rift, are irregular patches in character and referred to as dark cloud constellations.

Not much more insightful but here is another article.

https://astrobob.areavoices.com/2018/12/28/behold-the-orion-nebula-winters-most-beautiful-flower/

 

 

Interesting link Iain - thanks for that.

I can't resist returning your post with this fascinating movie "fly by" of that region of M42 which was recently compiled combining Hubble and Spitzer data:

 

[scarp15]

Wow quite a ride, the 3D sensation is quite impressive.