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Old 16-11-2010, 08:38 PM
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Paddy (Patrick)
Canis Minor

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More SMC observations 4/11/2010

Dear all,

Here are some notes on Small Magellanic Cloud objects from an observing session on November 4th. Haven't had a chance to type them up til now. The obs start with some smaller objects near NGC 104, some faint, some brighter and then move to the many bright objects near NGC 346. Some further notes on this area to follow.

Thanks for reading.

Telescope 410mm (16”) f4.9 tri-dob reflector
Eyepieces 28mm UWAN, 17,13,9 mm Naglers, Paracorr
Navigation: My own charts of the Small Magellanic Cloud
Further reference: “Visual Atlas of the Small Magellanic Cloud” by Mati Morel, “Star Clusters” by Archinal and Hynes.

First light for my charts and for my new Moonlight focuser.

Transparency excellent 7/7
Seeing poor 3/5

2300

Just to the south of a line of stars to the south of NGC 104 is

Kron 3/Lindsay 8 OC in SMC

132X A reasonable sized (perhaps 2’ across) rough oval of distinct quintessence between the westernmost pair of an E-W line of 4 stars. Brighter in the centre with brightness diminishing smoothly towards the soft edge of the cluster. No resolvable stars in the cluster itself. 175X shows a slightly dark crescent in the cluster on its north side with the convex side facing north. The southern part of the cluster is to the south of the two foreground stars. Doesn’t brighten much with UHC filter, but neither is Kron 3’s brightness diminished by the filter.

NGC 152 OC in SMC

175X Looks about the same size as Kron 3 but at least a magnitude fainter. Somewhat irregular in shape with small projections to the east and NW, but generally ovoid. There seems to be a slight darkening towards the eastern end and a small brightening further to the east again. Becomes much fainter with UHC filter.

Kron 7/Lindsay 11 OC in SMC

175X This is a barely perceptible brightening against the velvet black sky located between NGC 152 and Kron 3. Slightly easier to make out with UHC filter. Seems about the same size as Kron 3.

Lindsay 1 OC in SMC

175X This is a fairly large (by the standards of this area of sky) circle of subtle luminosity, perhaps about 5’ across. With direct vision the brightness appears very even, but with averted vision, there is some patchiness and the hint of and integral sign shaped brightening running E-W through the centre of the cluster. There is a hint of a few resolvable stars. Quite faint and not responsive to UHC filter.

Lindsay 2 OC in SMC

175X Another very faint oval of brightness – would be very easy to miss if you didn’t know where to find it. Significantly small that Lindsay 1, perhaps about 1’ across. More distinct SE-NW oval with UHC filter and appears about 2’ across, suggesting presence of emission nebula.

I move to the spectacular NGC 346 area

NGC 346 OC in SMC

175X This is embedded in the larger Henize nebula 11. NGC 346 is a very bright area spanning about 7’x4’ with a delightful bright knot of resolvable stars in the centre. The NGC 346 component appears curved with the convex to the west, fatter to the north. Henize N11 is a smooth area of haze which appears about 3x the size of NGC 346 which fades out evenly, a few resolvable stars scattered throughout. N11 extends much further to the east of NGC 346 than to the west. There is a little darkening of Henize N11 to the east and then a faint brightening before it disappears completely. Both NGC 346 and N11 brighten considerably with UHC filter and the edge of N11 appears sharper with UHC filter. N11 sprawls off to the east and north with a branch spreading into IC 1611. There is a flat edge to the south west.

About 10’ to the west is

Lindsay 56 OC in SMC

175X A tiny bright knot which appears somewhat granular suggesting tightly packed stars. This is so compact it appears stellar at first glance also brightens with UHC filter.

A further 12’ to the west is

NGC 330 OC in SMC

175X Larger than Lindsay 56 but smaller than the core of NGC 346, this is a very beautiful little pack of stars, very bright in the centre with a distinct N-S s- curve of brightness and resolvable stars giving an appearance akin to an open spiral galaxy. Perhaps about 2’x1’. Enhanced by UHC filter, but not to the extent that NGC 346 is.

To the south of NGC 346 is

IC 1611 OC in SMC

175X Another bright but small knot of luminosity, this is somewhat larger than Lindsay 56 but smaller and fainter than NGC 330. It forms a triangle with 2 other small fainter discs of light. The first ( to the southwest and is larger and fainter than IC 1611 and the smallest of the 3 is further to the south. IC 1611 remains distinct with UHC filter, but the other two areas dim markedly.

To the east of NGC 346 is

NGC 371 OC in SMC

175X A quite large circle of many resolvable stars and luminosity, only slightly smaller than the magnificent NGC346/N11 complex. The haze extends in an anvil shaped projection to the southeast and in a second projection to the northwest. The circular central portion of 371 brightens considerably with UHC, but the projections become fainter.

About 10’ to the south of NGC 371 is

Kron 50 OC in SMC

175X An irregular patch of haze with a slight point to the east. It appears a bit like a comet with a very wide tail with a more defined core at the eastern end. Perhaps about 1’ across. Almost disappears with UHC filter.

NGC 395 OC in SMC

175X This is significantly fainter than 346 and 371. It is an arrowhead shape of faint resolvable stars and luminosity pointing south with a chunk of darkening at its northern edge. 5’ to the south is IC 1624, a small luminous knot against a faint haze which appears to extend from NGC 395. There appears to be a larger area of faint haze in which two brighter areas – NGC 395 and IC 1624 – are embedded. UHC filter makes these two bright areas more distinct, the background haze visible but fainter. The arrowhead shape of 395 remains and looks about 5’ long and about 3’ wide at its base. IC 1624 appears about 1’x2’

Lindsay 84 OC in SMC


175X 5’ diameter disc of haze with brighter centre fading gradually to soft edge, containing a few faintly resolved stars. Tends to blend in with multitude of background SMC stars. Quite bright and much more distinct with UHC filter.
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Old 17-11-2010, 04:19 PM
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michaellxv (Michael)
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Great report Paddy. That's a very impressive list of objects you can see in the SMC.
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Old 17-11-2010, 06:58 PM
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Wow Paddy, what an excellent report, I really enjoyed it. Thankyou.

Is touring the SMC looking for these objects more for experienced observers? They seem difficult. This obs report (printed) would be a great guide to help me if the degree of difficulty is not so great, but it sounds hard . Do I need dark skies to observe all these objects within it?
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Old 17-11-2010, 07:15 PM
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astroron (Ron)
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Paddy, I have observed most of those in the 16" , but it is always a pleasure to read a well written report
Suzy it is more to do with identification on quite a few of those objects ,but a dark sky would make it a lot easier

Last edited by astroron; 17-11-2010 at 07:26 PM.
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Old 18-11-2010, 12:33 AM
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Great Report as usual Paddy. These objects don't sound too difficult, I intend to tackle them with Paddy's charts once full moon season is over NGC 346 is certainly impressive, basically a pseudo-barred spiral!
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Old 18-11-2010, 10:24 AM
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Paddy (Patrick)
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Thanks all for your responses.

Suzy, most of them would not be too hard. Only Kron 7 and Lindsay's 1 and 2 are very faint. Kron 3 is quite bright and I have no idea why it's not an NGC - I think people often confuse it with NGC 152 which is fainter but bigger. So I think you'd get most of the objects on the charts even with light pollution. The second part of the report which I'm still typing up includes obs with 15x70 binoculars as I wanted to see what could be picked up with these and I was surprised by how many SMC DSOs can be picked up just with binos. As Ron says, the challenge is knowing what's what. But if you start with the 3 bright patches in the tail of the comma of the SMC (NGCs 330, 346 & 371) you'll be able to identify most of the bits in the east. For the west, I've found the key is a right angled triangle asterism between NGC 104 and the body of the SMC. I'll mark it on one of my charts when I get a chance. I think you'd have quite a bit of fun exploring the area.
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