NGC2174 & NGC2175 - The Monkey Head Nebula and its associated open cluster
NGC2174 & NGC2175 - The Monkey Head Nebula and its associated open cluster
NGC2174/75
Orion
Emission Nebula(NGC2174) & Open Cluster(NGC2175)
NGC2174
IC2159
Sh 2-252
RA 06 09 42
DEC 20 29 00
Size 29' x 27'
Mag 6.8
NGC2175
RA 06 10 53
DEC 20 36 36
Size 5.0'
NGC2174/75 is an emission nebula/open cluster pair in northern Orion. Lying at a distance of nearly 6400 light years near the Gemini & Taurus borders, this pair were first discovered by Italian astronomer and comet hunter Giovanni Batista Hodierna in 1654 and again "rediscovered" in 1857 by German Carl Christian Bruhns.
NGC2174 is a beautiful view in scopes of nearly all sizes but due to it's rather compactness, lower power EP's probably offer the best view. I would suspect that scopes 12" and larger would probably offer the best views. 2174 is about twice as large as the OC 2175 and responds very well to OIII and UHC filters. 2175 can be a bit difficult to detect within the glow of 2174. The nebula is rather bright and apparent in the EP and shouldn't prove too difficult for observers. The nebula also has very nice mottling, streaks and dark lanes throughout lending itself a resemblance to the Lagoon Nebula in Sagittarius. 2175 has also been given the moniker the "Monkey Head Nebula" but for the life of me I just can't see the resemblance. NGC2175, the associated open cluster is a matter of question for me as well. The OC is often neglected in observing reports and gets lost in the nebulosity of 2174. I, for one, do not have any observing notes of 2174/75 where I make a distinct reference to observing the open. My notes primarily focus on the nebula. A quick search online reveals that many other observers fall to the same fate.
Interestingly, there are many cases online where NGC2174 and 2175 are confused for one another. I found so many online sources and observing reports where NGC2174 is referenced as the open cluster and NGC2175 is the nebula. Even an article and image on Sky and Telescope I found incorrectly title 2175 as the nebula. I wonder where the confusion started. Burnhams lists both 2174/75 as the nebula and doesn't even make a reference to the OC. The NGC Project assigns 2174 to the prominent knot within the nebula and 2175 to the nebula as a whole. I'm hoping Steve will chime in to help us clear this confusion. For the purposes of this OOTW, I referenced Simbad as well as Megastar which both identify the nebula as NGC2174. I must admit, I had a difficult time keeping numbers and references straight trying compile some information for this OOTW.
Here is a link to a NASA PDF highlighting pillars within NGC2174 (not unlike the Pillars of Creation in the M16) http://amazingspace.org/uploads/pdf/name/24/lp_ngc_2174_pillars_in_the_monkey_head_nebula.pdf
And as always
Give it a go and let us know!!
©HST
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