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NGC 1746

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#1 drbyyz

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Posted 09 December 2012 - 11:38 AM

Spent last night working on NGC objects in the Orion/Taurus region trying to get my Herschel 400 list count up. Pointed the scope to this gem and was really sad to see it wasn't included in the 400. I understand the list was edited down so that there weren't tons of similar items on it, but this is one of my new favorites. If you aren't familiar with it, check it out!

Fairly easy to find by starhopping across Taurus and a GoTo scope would have it in the field of view very easily. It's large and bright, should be easy for almost anyone to find. Lots of fun shapes and tons of stars in the FOV. After doing a little internet research after observing it, I was interested to find out it's actually 3 NGC Objects, 1746, 1750 and 1758. Got a kick out of that since in my observing notes I wrote: "Looks like 2 open clusters crammed together with a smaller asterism that could be its own cluster as well."

This one won't be on your Herschel 400 list, so take a look, it's in prime observing position.

#2 LivingNDixie

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Posted 09 December 2012 - 01:11 PM

Interesting. I will have to make a effort to see this one.

#3 David Knisely

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Posted 09 December 2012 - 02:14 PM

There is some question on the identify of NGC 1746 with some suggesting it is NGC 1750 (or that NGC 1750 is actually inside NGC 1746). NGC 1750 is in the Herschel II list and strongly overlaps NGC 1748. One paper suggest that they are at roughly the same distance and may actually penetrate each other (i.e. maybe only one cluster), but if you are seeing one cluster, you are very probably seeing both. Clear skies to you.

#4 JakeSaloranta

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Posted 09 December 2012 - 02:40 PM

Check out NGC/IC Project explanation for this cluster(s). Also, to be precise, NGC 1746 was discovered by D'Arrest, not Herschel so it can't be a H400 object. Herschel discovered -50 and 58.

Here is my version:
Posted Image

#5 LivingNDixie

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Posted 09 December 2012 - 04:42 PM

Jake,
Great sketch, that looks like a flying reindeer to me. And by the power that I invest in myself I am going to start calling NGC 1746 "the flying reindeer cluster." :lol:

Okay all kidding aside, that is a good sketch!

#6 Feidb

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Posted 09 December 2012 - 04:42 PM

I've logged both 1746 and 1758. I assumed 1746 was the brighter stars in this mess while 1758 was most of the dimmer stars in the background. The reason is that 1746 has a listed mag. of 6.1 while the other doesn't list a mag. To sort them out, that's how I drew them. Maybe I'm wrong in that assumption but I don't know how else to separate the two at this point.

#7 IVM

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Posted 09 December 2012 - 05:13 PM

After Preston mentioned it, I also see a very nice flying reindeer in Jake's sketch. On the DSS, though, I (now) see a much more robust animal, something like a bull (a stylized, thick bull in Merrill Lynch's logo).

The really funny thing is that NGC 1750 is not in "my" Herschel 400, which is O'Meara's Herschel 400. Nor is any other part of this cluster. It is in Herschel 400 though according to SEDS and one other site I found, so there is no arguing here that it's not.

When I found out this now it explained why I could not find any record of seeing this cluster. Here is, in a way, a Herschel 400 object that I haven't seen! Generally I should say that I am not a big fan of Herschel's class VIII clusters, although they may be a breath of fresh air as a diversion on a long night of observing many typical, more compact objects.

EDIT: Above where I said "1750" I really meant this number. 1758 that David mentions is not in Herschel 400 according to the same sources that I used here to find that 1750 is. What a convoluted story.

#8 drbyyz

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Posted 09 December 2012 - 09:32 PM

Hmm, the list I'm using does not include 1746,50 or 58.

Oh and I see the reindeer, fun.

#9 David Knisely

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Posted 10 December 2012 - 02:01 AM

After Preston mentioned it, I also see a very nice flying reindeer in Jake's sketch. On the DSS, though, I (now) see a much more robust animal, something like a bull (a stylized, thick bull in Merrill Lynch's logo).

The really funny thing is that NGC 1750 is not in "my" Herschel 400, which is O'Meara's Herschel 400. Nor is any other part of this cluster. It is in Herschel 400 though according to SEDS and one other site I found, so there is no arguing here that it's not.

When I found out this now it explained why I could not find any record of seeing this cluster. Here is, in a way, a Herschel 400 object that I haven't seen! Generally I should say that I am not a big fan of Herschel's class VIII clusters, although they may be a breath of fresh air as a diversion on a long night of observing many typical, more compact objects.

EDIT: Above where I said "1750" I really meant this number. 1758 that David mentions is not in Herschel 400 according to the same sources that I used here to find that 1750 is. What a convoluted story.


Nope, I screwed up, as NGC 1750 is in the Herschel II listing and not in the original 400. I ran into the confusing two-cluster designation not long after I started working on the Herschel II's (Megastar doesn't list NGC 1750, but my old 1st edition of Uranometria 2000 showed all three). In any case, if you see NGC 1746, chances are you are also able to see NGC 1750 (and vice-versa). Clear skies to you.

#10 IVM

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Posted 10 December 2012 - 09:49 AM

Archinal and Hynes do not have a special note about this cluster, but in the table they say:

1746, cluster, contains 1750 and 1758. 40' group of ~10 bright stars.

1750, part of cluster, part of 1746. Herschel's VIII.43.

1758, cluster, part of 1746. Probably clump on E side of 1746 and 1750 overall group.

Steinicke writes about d'Arrests discovery 1746:

The inconspicuous group 1746 overlaps with the open clusters 1750 (VIII.43) and 1758 (VI.21)... Both are significant objects, 1750 being the brighter one. Owing to their different distances, they are not physically connected. D'Arrest's group is located in the middle - a mere optical mix of stars of both clusters (Leiter F 2007, Ein Trio von Offenen Sternhaufen? VdSF 22 52-54).

And I thought Herschel 400 II/ Herschel class VIII clusters in Cygnus were confusing!

#11 David Knisely

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Posted 10 December 2012 - 01:54 PM

Archinal and Hynes do not have a special note about this cluster, but in the table they say:

1746, cluster, contains 1750 and 1758. 40' group of ~10 bright stars.

1750, part of cluster, part of 1746. Herschel's VIII.43.

1758, cluster, part of 1746. Probably clump on E side of 1746 and 1750 overall group.

Steinicke writes about d'Arrests discovery 1746:

The inconspicuous group 1746 overlaps with the open clusters 1750 (VIII.43) and 1758 (VI.21)... Both are significant objects, 1750 being the brighter one. Owing to their different distances, they are not physically connected. D'Arrest's group is located in the middle - a mere optical mix of stars of both clusters (Leiter F 2007, Ein Trio von Offenen Sternhaufen? VdSF 22 52-54).

And I thought Herschel 400 II/ Herschel class VIII clusters in Cygnus were confusing!


This might make good reading:

http://adsabs.harvar...BaltA...1..125S

http://link.springer...8814371?LI=true

These two seem to indicate that NGC 1476 is not actually an open cluster. Clear skies to you.

#12 Feidb

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Posted 10 December 2012 - 03:44 PM

Mr. David.

That clears/confuses the matter even more! Thanks for those links. I don't know whether to edit my data or just leave it be. As I described it, it's a mess of stars.

#13 David Knisely

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Posted 11 December 2012 - 02:12 AM

Mr. David.

That clears/confuses the matter even more! Thanks for those links. I don't know whether to edit my data or just leave it be. As I described it, it's a mess of stars.


I don't know either, as it seems nobody can decide anything for certain here. All I know is that if/when I submit all the descriptions for the Herschel II's, NGC 1750 will be described as:

"Part of NGC 1748/58? Large irregular group of 20 to 30 stars, not terribly bright with a small secondary concentration of very faint stars in the east-northeastern half of the main cluster. Perhaps 20 additional stars in this sub-group. Questionable which cluster really exists!

Clear skies to you.

#14 Feidb

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Posted 11 December 2012 - 10:02 AM

David,

I think my final description will be something like that too. Thanks!

Fred






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