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New Globular Cluster Discovered

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#1 KidOrion

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Posted 28 March 2014 - 12:55 PM

Not to steal your topic from that other place, Jimi--sorry!

There's a "new" member of the Milky Way's retinue of globular clusters:

Discovery announcement paper

This one's in Crater, at RA 11h 36m 16s, Dec -10* 52' 38. I expect that someone here will have observed it by the time the weekend's out. :lol:

#2 kt4hx

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Posted 28 March 2014 - 02:01 PM

Looks to be about 1 degree south of Theta Crateris. Thanks for the link

#3 Alvin Huey

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Posted 29 March 2014 - 12:12 PM

I haven't looked for it yet (weather is crud this weekend), but did include it in my Globular Cluster observing guide. (Page 26)

http://www.faintfuzz...ingGuides2.html

#4 mattyfatz

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Posted 29 March 2014 - 03:03 PM

Quite amazing that there are Globulars yet to be discovered.
What's the Mag of this thing. I keep seeing -4.3.. but that's obviously not what I mean.

#5 kt4hx

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Posted 30 March 2014 - 11:16 AM

I haven't looked for it yet (weather is crud this weekend), but did include it in my Globular Cluster observing guide. (Page 26)

http://www.faintfuzz...ingGuides2.html


Thanks Alvin, already downloaded. I see you also updated the M3 listing as well. Appreciate the charts on the new one.

#6 hokkaido53

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Posted 30 March 2014 - 11:37 AM

Quite amazing that there are Globulars yet to be discovered.
What's the Mag of this thing. I keep seeing -4.3.. but that's obviously not what I mean.


Is this a new kind of magnitude scale? I think only Venus gets to be -4.3.

Roy

#7 Sasa

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Posted 30 March 2014 - 12:22 PM

Quite amazing that there are Globulars yet to be discovered.
What's the Mag of this thing. I keep seeing -4.3.. but that's obviously not what I mean.


You have to look into the discovery paper. The authors state that modulus m-M=20.81m and M(V)=-4.3. This makes visual magnitude to be around 16.5, definitely out of reach of my 11cm refractor...

#8 Dave Mitsky

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Posted 30 March 2014 - 10:51 PM

Quite amazing that there are Globulars yet to be discovered.
What's the Mag of this thing. I keep seeing -4.3.. but that's obviously not what I mean.


Is this a new kind of magnitude scale? I think only Venus gets to be -4.3.

Roy


In the distance modulus formula, M stands for absolute magnitude and m for apparent magnitude.

Dave Mitsky
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#9 hokkaido53

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Posted 31 March 2014 - 10:45 AM


You have to look into the discovery paper. The authors state that modulus m-M=20.81m and M(V)=-4.3. This makes visual magnitude to be around 16.5, definitely out of reach of my 11cm refractor...


It's just out of reach of my 18" reflector, unless it's an unusually clear desert night.

Roy in Taos

#10 GlennLeDrew

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Posted 31 March 2014 - 10:21 PM

The integrated magnitude tells only part of the tale; the surface brightness is important, too. That it took till now to find suggests to me that this cluster must have pretty low surface brightness, else it would have been reasonably apparent on the POSS plates (whivh penetrate to ~22m on point sources, iirc.)

#11 Astrojensen

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Posted 01 April 2014 - 10:48 AM

Surprisingly, it IS visible on the red POSS II plate. Quite well, actually, these things considered, although it doesn't exactly call attention to itself.


Clear skies!
Thomas, Denmark

#12 GlennLeDrew

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Posted 01 April 2014 - 01:13 PM

Thanks for checking, Thomas. Any estimate as to a qualitative or comparative surface brightness?

#13 Alvin Huey

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Posted 01 April 2014 - 06:03 PM

According to the DeepSkyForum site where this object was originally reported, Jimi observed it with direct vision with his 48" reflector.

#14 nytecam

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Posted 01 April 2014 - 06:36 PM

This is a snap of the new GC field from tonight but will have to stack images tomorrow to see if anything is there :o

I don't like to be beaten but this one has - the stack of images is noisy and no GC evident :bawling: I'll blame the Saharan dust and low altitude :lol:

Attached Files



#15 kt4hx

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Posted 03 April 2014 - 03:06 PM

Keep trying! As has been said, it likely has a very low surface brightness so it might be a real challenge for you.

#16 Rich (RLTYS)

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Posted 04 April 2014 - 11:12 AM

Took this image of the area of this newly discovered globular cluster and I think I managed to capture a few of its brighter members. I hope to be able to reimage this cluster with the larger Slooh telescope soon.

Rich (RLTYS)

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#17 GlennLeDrew

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Posted 04 April 2014 - 11:26 AM

Mighty low surface brightness, indeed. Rich; your image probably has not captured much more than noise here. The stars are almost certainly (too-bright-for-the-cluster) field stars, I think.

#18 nytecam

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Posted 05 April 2014 - 02:34 AM

Took this image of the area of this newly discovered globular cluster and I think I managed to capture a few of its brighter members. I hope to be able to reimage this cluster with the larger Slooh telescope soon. Rich (RLTYS)

Contrary to Glenn's comments I think you've done exceptionally well - your shot compares favourably with Sloan DSS[Wikisky] - well done - we await your deeper image :bow:



#19 Rich (RLTYS)

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Posted 05 April 2014 - 06:51 AM

Nytecam thanks, I compared my image to the one in the published discovery paper and the brighter stars seem to match. I definitely don't think its noise.

Rich (RLTYS)

#20 GlennLeDrew

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Posted 05 April 2014 - 11:32 AM

I had first thought the visual aspect to more resemble a sparser, old open cluster due to the great disparity in luminosity between the handful of brightest members and the light from the rest of the unresolved stars, leading me to mistakenly take those resolved stars to be comparatively too bright for membership in a globular system. But I now see that a few of those stars are quite likely red giants, with, I suspect, a blue straggler or two. The rest of the cluster's light is noise dominated, though.

#21 Feidb

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Posted 05 April 2014 - 12:10 PM

Geez, thought I could see it with my grandson's 76mm Cometron! Oh well...

#22 Rich (RLTYS)

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Posted 06 April 2014 - 07:55 AM

Was finally able to image this new globular cluster with the Slooh 20" scope and you can definitely see the cluster.

Rich (RLTYS)

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#23 Astrodj

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Posted 07 April 2014 - 11:12 PM

Wow, Rich. That is really cool. Nice Job!

#24 hokkaido53

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Posted 08 April 2014 - 07:01 AM

Was finally able to image this new globular cluster with the Slooh 20" scope and you can definitely see the cluster.

Rich (RLTYS)

Nice...What is its magnitude?

- Roy

#25 kt4hx

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Posted 08 April 2014 - 11:21 AM

[/quote]
Nice...What is its magnitude?

- Roy [/quote]

Based on data discussed in previous posts in this thread, I believe it works out to mag 16.51. However, given how long it went undiscovered, I would have to suspect its surface brightness is quite dim.

And agreed, that is a beautiful image there Rich!






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