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Old 15-01-2018, 12:16 PM
Tropo-Bob (Bob)
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NGC 1851 - Globular

I have long been intrigued with this globular. I first observed it in 1981 with my 8" F7 reflector and made the note: "It's like a dull, torchlight pointed at me, but shining through a mist."

I had the same impression when I observed it many years later with my 12" F5 Dob. I observed it 3 nights ago with my new Tak 100D (F7.4) and still saw that effect with the lessor aperture.

In the Stephen James O'Meara Calwell Objects (P 291), Stephen says that ; "The overall impression is that of the great Hercules globular M13 seen through a fog." NGC 1851 is also known at Caldwell 73.

I have seen this 'fog/mist' affect only on this globular. I am interested if others see it? Strangely, Hershel saw it, but only with his right eye; not his left eye! (Ibid P288).

On researching, this globular has a very colourful past with indications that it may be a merger of two previous globulars and that it may have lost from a nearby Dwarf Galaxy. Also there are studies indicating a halo extending around the globular. There are a surprising number of studies on the Web concerning this cluster.

More information:

https://britastro.org/node/6857

https://books.google.com.au/books?id...201851&f=false

https://arizona.pure.elsevier.com/en...bular-ngc-1851

https://www.aanda.org/articles/aa/pd...aa17269-11.pdf
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Old 20-01-2018, 03:27 PM
bigjoe (JOSEPH)
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Re Glob

Quote:
Originally Posted by Tropo-Bob View Post
I have long been intrigued with this globular. I first observed it in 1981 with my 8" F7 reflector and made the note: "It's like a dull, torchlight pointed at me, but shining through a mist."

I had the same impression when I observed it many years later with my 12" F5 Dob. I observed it 3 nights ago with my new Tak 100D (F7.4) and still saw that effect with the lessor aperture.

In the Stephen James O'Meara Calwell Objects (P 291), Stephen says that ; "The overall impression is that of the great Hercules globular M13 seen through a fog." NGC 1851 is also known at Caldwell 73.

I have seen this 'fog/mist' affect only on this globular. I am interested if others see it? Strangely, Hershel saw it, but only with his right eye; not his left eye! (Ibid P288).

On researching, this globular has a very colourful past with indications that it may be a merger of two previous globulars and that it may have lost from a nearby Dwarf Galaxy. Also there are studies indicating a halo extending around the globular. There are a surprising number of studies on the Web concerning this cluster.

More information:

https://britastro.org/node/6857

https://books.google.com.au/books?id...201851&f=false

https://arizona.pure.elsevier.com/en...bular-ngc-1851

https://www.aanda.org/articles/aa/pd...aa17269-11.pdf
Bob..
Hard to resolve much in my 6" needs much more I feel.. prob 10 inch Dob at least.... at Mag 7 and 12 minutes of arc.
Easy to locate as below...from Skysafari Plus
bigjoe
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Last edited by bigjoe; 20-01-2018 at 04:13 PM. Reason: Adding info
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Old 07-02-2018, 12:09 PM
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Tinderboxsky (Steve)
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I had a chance to observe this globular cluster last night in very good seeing and transparency.
My sense of the scene was a bright very condensed central spot surrounded by a halo of light that was brighter closer to the central spot. So, yes, it certainly appeared just as you had described. I spent a while observing trying to check that I was not being misled to simply seeing what you had reported.
At one point I hopped over to NGC 2808 in Carina to compare observations. Here, there is a quite broad bright central core and a surrounding spray of light, much of which, shows resolved pin point stars and the rest looks right on the edge of resolving into individual stars. This did not look mist like.
It was an interesting target. I too, shall be interested to hear of others observations.
Scope: Vixen NA140SS on TRex mount and Pan24, LVW 13 & 8 eyepieces.
Quote:
Originally Posted by Tropo-Bob View Post
I have long been intrigued with this globular. I first observed it in 1981 with my 8" F7 reflector and made the note: "It's like a dull, torchlight pointed at me, but shining through a mist."

I had the same impression when I observed it many years later with my 12" F5 Dob. I observed it 3 nights ago with my new Tak 100D (F7.4) and still saw that effect with the lessor aperture.

In the Stephen James O'Meara Calwell Objects (P 291), Stephen says that ; "The overall impression is that of the great Hercules globular M13 seen through a fog." NGC 1851 is also known at Caldwell 73.

I have seen this 'fog/mist' affect only on this globular. I am interested if others see it? Strangely, Hershel saw it, but only with his right eye; not his left eye! (Ibid P288).
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Old 07-02-2018, 12:54 PM
bigjoe (JOSEPH)
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Quote:
Originally Posted by Tinderboxsky View Post
I had a chance to observe this globular cluster last night in very good seeing and transparency.
My sense of the scene was a bright very condensed central spot surrounded by a halo of light that was brighter closer to the central spot. So, yes, it certainly appeared just as you had described. I spent a while observing trying to check that I was not being misled to simply seeing what you had reported.
At one point I hopped over to NGC 2808 in Carina to compare observations. Here, there is a quite broad bright central core and a surrounding spray of light, much of which, shows resolved pin point stars and the rest looks right on the edge of resolving into individual stars. This did not look mist like.
It was an interesting target. I too, shall be interested to hear of others observations.
Scope: Vixen NA140SS on TRex mount and Pan24, LVW 13 & 8 eyepieces.
Youve got good eyes Steve .. "Eyes like O'meara " As they say..
Have yet to look circumspectly at this one..with clouds and all..had fun with JABBAH and Antares recently though.

Will give it a shot tonight; along with the brilliant Clobular N2808 in Carina, which I find wants aperture for a good show, and for others, is right near the wonderful Upsilon Carinae..part of the Diamond Cross Asterism...so much in that area ...were spoilt.
Enjoyed your observation of these objects Steve.
bigjoe.

Last edited by bigjoe; 07-02-2018 at 04:12 PM. Reason: Adding
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Old 11-06-2023, 07:50 PM
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gaseous (Patrick)
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Sorry to resurrect an old thread, but I was looking for posts on Jabbah and for some reason this post on NGC 1851 came up. My notes from Feb this year, taken under Bortle 2 skies with a 20" dob, make the following observation: "Lovely moderate size very bright globular cluster with a dense mottled core." I certainly didn't see any mist of note, but my eyes probably aren't what they once were, either.



On to Jabbah (Nu Scorpii, southern double double). Saw this for the first time last night - what a super little pair of pairs! With my 8" dob under Bortle 5 skies, the dimmer pair was an easy split at about 150x, whereas the brighter pair required up to 350x and were still more of a figure 8 than showing an actual separation. I can't imagine how rewarding it would be to be splitting super tight doubles out in the Atacama Desert or somewhere with similar great seeing conditions - Brisbane usually sucks the big one in that regard.
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