June obs' cha'ge- object selection process

[mental4astro (Alexander)]

Hi all,

I thought I'd get in early to get the ball started with the selection process.

Shall we maintain the object group theme? May I suggest Globular Clusters for June?

To this end, my four candidates as always are varied:

Omega Centuri- the big kahuna

M4- in Scorpius. Striking linear formations seen even in modest scopes.

M5- in Serpens Caput. One of the other big GC's, not often mentioned in my circle of objects. Will be tricky from more southerly latitudes.

NGC 6453- one of my fav's. It is a tiny, difficult bugger. It is in the same line of sight as the big bugger M7. Not only, but also the open cluster Tr 30, and the planetary nebula PK356-4.1, lie within the bounds of M7. Here is the big challenge with this one. Isolating the various components.

Any other candidates?

Mental.

[Rob_K]

Good stuff Alexander, my favorite objects! NGC 6453 is a great globular, a challenge belying its mag 9.9 brightness!

To go with the bright ones you listed, I'd like to add two globulars that are very challenging in small-medium scopes. I have seen both before in dark skies through my 4.5" reflector.

- First is NGC 6256 in Scorpius, a faint mag 11.3 globular, for me an extremely dim, smallish glow in averted vision.

- The second is NGC 6426 in Ophiuchus, a mag 11.2 globular, another extremely dim averted vision job for me.

Cheers -

[renormalised (Carl)]

UKS-1...the dimmest at +17.3 mag, or thereabouts RA: 17:54:27.2, DEC: -24:08:43

AM1 (ESO 201-10)...the farthest at 400Kly, RA: 3:55:02.7, DEC: -49:36:52, about +15.7 mag

Very difficult. May have to get images of these fellas rather than spy them visually. In any case, two hard targets

[Steffen]

I suppose June is also a good month to behold our northern winter guests, M13 in Hercules and M57 and the double double in Lyra. Provided you have a fairly unobstructed northern horizon.

Cheers
Steffen

[Rob_K]

Originally Posted by renormalised

UKS-1...the dimmest at +17.3 mag, or thereabouts RA: 17:54:27.2, DEC: -24:08:43

Not unless you've got about a metre aperture Carl! Barbara Wilson & Larry Mitchell saw it in superb conditions at 663x in a 36" telescope in 1997, at the very limit of the scope's capability. I don't think anything less will get it. I can't find any other reference to visual observations, other than failures. It is heavily obscured by interstellar dust.

http://www.astronomy-mall.com/Advent...ce/obscure.htm

Cheers -

[GrampianStars (Rob)]

Just a coupla Globs, for 6" dobs +
should be reasonably visual

NGC 4590 M68 Hya" "Mag 8.2
NGC 4897 Lib" "Mag 8.6
NGC 5927 Lup" "Mag 8.3
NGC 5946 Nor" "Mag 8.3
NGC 6031 Nor" "Mag 8.5
NGC 6171 M107 Oph" "Mag 8.1
NGC 6235 Oph" "Mag 8.9
NGC 6293 Oph" "Mag 8.2
NGC 6304 Oph" "Mag 8.4
NGC 6352 Ara" "Mag 8.2
NGC 6558 Sag" "Mag 8.7
NGC 6624 Sag" "Mag 8.3
NGC 6634 M69 Sag" "Mag 7.9
NGC 6542 Sag" "Mag 8.8
NGC 6652 Sag" "Mag 8.9
NGC 6681 M70 Sag" "Mag 8.1
NGC 6712 Scut" "Mag 8.2
NGC 6717 Sag" "Mag 8.6
NGC 6864 M75 Sag" "Mag 8.6

[renormalised (Carl)]

Originally Posted by Rob_K

Not unless you've got about a metre aperture Carl! Barbara Wilson & Larry Mitchell saw it in superb conditions at 663x in a 36" telescope in 1997, at the very limit of the scope's capability. I don't think anything less will get it. I can't find any other reference to visual observations, other than failures. It is heavily obscured by interstellar dust.

http://www.astronomy-mall.com/Advent...ce/obscure.htm

Cheers -

Yes, I know. That's why I said it might be better to image these fellas, or have something like a GStar camera hooked up and view it on your PC's screen or a monitor. Not a purists way of viewing it visually, but viewing it, it is

[sjastro]

AM1 (ESO 201-10)...the farthest at 400Kly, RA: 3:55:02.7, DEC: -49:36:52, about +15.7 mag

Very difficult. May have to get images of these fellas rather than spy them visually. In any case, two hard targets

Ah yes my old friend AM-1. Not having a GOTO mount made it extremely difficult to locate and centre on the CCD even after a 1 minute exposure.

A 140 minute exposure is not deep enough.
http://users.westconnect.com.au/~sjastro/am1.html

Regards

Steven

[GrampianStars (Rob)]

Originally Posted by sjastro

.............
A 140 minute exposure is not deep enough.
http://users.westconnect.com.au/~sjastro/am1.html
Regards
Steven

Mmmm not bad having never searched 4 AM1 before
this is the 1st time I've ever seen it
A difficult little sucker Ehh!

[sjastro]

Originally Posted by GrampianStars

Mmmm not bad having never searched 4 AM1 before
this is the 1st time I've ever seen it
A difficult little sucker Ehh!

Absolutely.

I might be crazy enough to try UKS-1.

Regards

Steven

[renormalised (Carl)]

Very hard targets....best thing, especially for UKS-1, is to use the IR response of a mono imager without IR block, to look for it. That's where the GStar is good.

[mental4astro (Alexander)]

Shall we add an easier one to the mix too?

M22 is a brilliant GC in Sagittarius. It is heavily obscured by dust, which if it wasn't there, M22 would quite likely out shine Omega Cent..

Finalize the list then? Great mix of easy, tough and 'good luck' ones this time.

[Suzy]

Can't wait for this - it will be my first ob. challenge (if the weather gets lost). Yipee! Bring it on, I love globs!
Would you be kind to the beginners with smaller apertures 6-8", and give us a few- say 4?

[renormalised (Carl)]

Suzy, the first 4 are within range of 6-8" scopes

[mental4astro (Alexander)]

I have another suggestion for this month's challenge:

Shall we invite the imaging folks to join us with nailing the two exceptionally faint GC's? There are a couple of objects suggested this month that would be extremely difficult to spot. I don't think that there are too many people with 36"+ scopes out there capable of spotting a 17.3 magnitude GC. Yet many of the IIS imagers would be quite capable of doing a good job of it.

Suzy, Steffan has also suggested M13 & M57, plus there is also M22. Actually, any Messier object is well within range of a 6"er.

This month sees a jolly lot of candidates. From those suggested, here is my preference. Suggest another combo if you like:

Easy: Omega Cent., M4, M13 & M75 (the Messier ones being seen in the northern hemisphere)

More challlenging: NGC 6453, 6256, 6426, 6235.

"Good Luck": UKS-1 & AM-1

[Suzy]

Originally Posted by mental4astro

I have another suggestion for this month's challenge:

Shall we invite the imaging folks to join us with nailing the two exceptionally faint GC's?

I think that is a fabulous idea, and a fabulous list you have covered.
Are we able to get together once these challenges have been met and discuss them, including seeing the pics of the harder challenges? Is that what you'll normally do on this same thread?