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Old 04-03-2008, 08:14 AM
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goober (Doug)
No obs, raising Harrison

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Observation Report: 3 March 2008

Location: Melbourne
Time: 11pm - 1am
Seeing: 6 (Pickering)
Transparency: 5/10

Thumbing through the latest AS&T, debating whether to set up or go to bed. I read Les' binocular highlights featuring NGC 3766 and decided to set up and tour the clusters with an atlas. Ten minutes later I was at the eyepiece.

Beta Crucis / NGC4755 - just low power viewing at 22x. Lovely view, plenty of colour and contrast in the field. White Beta Crucis, it's ruddy close neighbour, another gold star close by, and the Jewel box. Iota and Lambda Crucis completed the picture.

NGC 3918 - planetary nebula in Centaurus. Star hopped from Beta Crucis across to Delta Crucis (not necessary, but I really need to polish up my L/R translation skills at the atlas/eyepiece). Kept going through chains of stars until I got to the Blue Planetary. There are so many stars in the field along the journey, it's easy to get lost, especially with left/right flipped. The planetary was easy to hold with direct vision at 49x, and a blue/grey colour. I bumped the power to 154x and studied it for around 10 minutes, but it didn't give up any more detail. Perhaps slightly oval.

Sirius - with 154x in the eyepiece, I swung over to Sirius for another go at Sirius B. I printed off a Cartes du Ciel chart to compare with the view at the eyepiece. The chart had stars down to magnitude 12.5, but I was seeing more. Not sure what is going on there - I'll check what catalogs it's using. Seeing wasn't as good as Friday night, however Sirius looked steady, in a blinding way. I couldn't see the companion I thought I saw a few nights ago with direct vision, so I let Sirius drift out of the field and watched the glare leave the field. Every time I saw a star suddenly pop out three or four seconds after Sirius left. I held it for five or six seconds before it to left the field. I tested internal reflections by moving the scope so Sirius was exiting at different locations around the field. The PA was slightly north of east - it wasn't in the same exit plane as Sirius. I'll keep an eye on this puppy (ahem) over the next few years and see what it does. I'm about 50% sure this is Sirius B. Les was right in his recent AS&T article - it is addictive.

Centaurus A - galaxy in Centaurus. Quite easy to pick out at 49x from the 'burbs. Saw the two halves quite clearly with hints of the lane using averted vision. The half with the star superimposed seemed brighter than the other half.

Omega Centauri - stunning as usual. I'm beginning to dislike this object as I forget to go after Centaurus' other wonders - the Tweezers, 5286, etc. All things I haven't checked out with this scope.

Cluster Hopping ... popped the 49x/1.73 degree 11mm Nagler back in and centre Acrux. Hopped to Zeta Crucis, onto Theta Crucis (both of them), and dipped into Musca to try to find NGC 4372. I used to view this a bit with my dobs and found it moderately difficult from Melbourne. Couldn't see a thing with the 4" refractor. Just washed out.

Cr 249 - open cluster in Centaurus. Hopped over the Lambda Centauri and had a look at Cr 249. Lambda Centauri had a milky glow to it from the almost invisible nebulosity (IC 2944, and nearby IC 2948). The cluster itself is interesting - long and narrow, around 30' in length. The shape of the cluster reminded me a bit of the constellation of Orion, after he'd had a session on the rack!

NGC 3766
- open cluster in Centaurus. Nice cluster, around 30+ stars resolved at 49x. Two obviously orange stars are immediately evident. I like getting a snap impression of a cluster, and this one struck me as being in the shape of a letter "W".

NGC 3532 - open cluster in Carina. Huge cluster, spread out over almost the entire 1.7 degree field at 49x. Stunning cluster.

Cr 240 / NGC 3572 - open cluster in Carina. (Is this the same object, two names?). Just over 1 degree south of NGC 3532. Sparse cluster (?) - resolved around 8 stars over 30' field.

Eta Carina - nebula in Carina. Spent ten minutes just tracing the nebulosity. Lovely object. The orange star, Eta, was surrounded by tiny pin-pricks of light - small stars embedded in the dust. I hadn't noticed that before - usually trying to resolve the homunculus. I could just make out the two lobes of the homunculus at 49x.

NGC 3293 - open cluster in Carina. Lovely, tight cluster about a degree from Eta Carina. I counted 35 stars I could easily resolve, with many more popping out, and vanishing as my eye raced to the spot. I see a rose, with petals, in this circular shaped cluster. Three stars tracing off to the east make a nice "stem".

NGC 3114 - open cluster in Carina. Large cluster, around 40'. Quite a striking shape, dominated by two almost complete circular loops of stars, one inside the other. The loop goes around three quarters of a circle, tracing from the south - west - north. Impression was two letters "C", one inside the other.

1am, the door opens and I get the "ahem, do you know what time it is" from the better half. Reluctantly, I stretch and think about packing up. I glance up and am stunned to see a band of cirrus cloud has come in and is over the area I'd been observing.

I'd been so intensely hopping down these clusters from Acrux, I hadn't looked up for an hour. Sounds crazy, but it's true. Atlas - eyepiece - notebook - atlas - eyepiece - notebook. I had taken the whole tour with the one eyepiece (11mm Nagler) at 49x - very rewarding.

I broke everything down and packed up. I get inside and see Mrs. Goober had just put an episode of Buffy on. Forty more minutes I could have had outside!
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Old 04-03-2008, 10:11 AM
Karlsson
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As always, I really enjoyed reading this, especially since your 'trip' overlapped to some extent with mine last night ...

Quote:
Originally Posted by goober View Post
The chart had stars down to magnitude 12.5, but I was seeing more. Not sure what is going on there - I'll check what catalogs it's using.
CdC uses the Tycho-catalogue down to about mag 12-ish. Like you I always see more than what's on my printed chart, which I find confusing. I tried to download the Guide Star Catalog down to mag. 14.5, but the download was exceedingly slow. Now I use CdC and Star Atlas Pro side by side - SAP Advanced comes with the GSC and can access the USNO catalogues, so for some time to come I can print more stars than I can ever see...
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Old 04-03-2008, 11:23 AM
你B
Its only a column of dust

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Good report as usual. I don't think NGC 3918 shows much in the way of detail at all, although observing it at 700x with my 12" I thought I could detect uneveness in its surface brightness but I'm not too sure.

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1am, the door opens and I get the "ahem, do you know what time it is" from the better half. Reluctantly, I stretch and think about packing up. I glance up and am stunned to see a band of cirrus cloud has come in and is over the area I'd been observing.

I broke everything down and packed up. I get inside and see Mrs. Goober had just put an episode of Buffy on. Forty more minutes I could have had outside!
Put her on a guilt trip......"You know hun, i could always be roaming the streets and getting high on dope and prostitutes"

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Originally Posted by goober View Post
I glance up and am stunned to see a band of cirrus cloud has come in and is over the area I'd been observing.
That's called the "melbourne factor"

Last edited by 你B; 04-03-2008 at 12:31 PM.
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Old 04-03-2008, 12:13 PM
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goober (Doug)
No obs, raising Harrison

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Quote:
Originally Posted by Karlsson View Post
CdC uses the Tycho-catalogue down to about mag 12-ish. Like you I always see more than what's on my printed chart, which I find confusing.
It caught me out because I'm sure some of the stars I was seeing were brighter than those plotted.

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Put her on a guilt trip......"You know hun, i could always be roaming the streets and getting high on dope and prostitutes"
I think she's quite happy to fling me into the back yard for a few hours!
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Old 04-03-2008, 08:31 PM
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WadeH (Wade)
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Sounds like you had a great night Doug.

You have given me a few ideas for my next evening out.

Margaret doesnt mind my telescopic forays, she says at least she knows were I am!
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Old 04-03-2008, 08:42 PM
你B
Its only a column of dust

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NGC 3918 is one I want to chase at extremely high mag, going out tomorrow morning with the 10", hoping for good seeing....
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Old 04-03-2008, 09:38 PM
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ngcles
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Hi Doug & All,

Another interesting read -- well put together. Keep trying on Sirius -- you never know (though I don't think you need further encouragement).

Interested in your impressions of NGC 3766 -- you saw 2 orange stars which is pretty much what I'd expect in the 4". With 8-10" there is third one. Two are close together on the NW side of the cluster and the third is just to the east of centre. All three are M0 Iab supergiants. The three are pretty easy to see in 10" and make the white stars look a bit "icy" by contrast. Must take a look next time to see if I can see the "W". This cluster truly is one of the rarely mentioned gems of the southern sky that if transplanted to say Cassiopeia, we'd never hear the end of ...

I see you rated the seeing in Melbourne as a 6, it was some of the best seeing in several months in Sydney last night. Transparency was about average though. I was working at the obs doing the practical component of a course I teach and we had a good assortment of ''scopes from 60mm refractor, 4.5" reflector, 10" S/C, 12" Dob and my 18". By 11pm, Saturn was breathtaking.

You could see that the outer edge of the "A" ring was slightly more diffuse than the sharper inner edge at Cassini, and the "A" rings' cold white colour contasted nicely with the more creamy "B" ring which (heading toward the disc of Saturn) faded into the dusky Crepe ring. We noted 7 moons in the 18" which were Titan, Rhea, Dione, Iapetus, Tethys, Enceladus and Mimas (very faint). The best view of Saturn I've had in some little time.

Re: NGC 3918, with my old 10" in excellent seeing, I have (quite some time ago) seen a couple of what looked like slightly dimmer fine lines across it at high power (didn't note the PA), but that doesnt seem to correspond to the images I've seen -- but that is the limit of what I could discern. I'm curious to know what the result of your intended high-magnification assault is 你B (and anyone else) (but make sure Uni comes first!!).

Best,


Les D

Last edited by ngcles; 04-03-2008 at 10:25 PM.
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Old 04-03-2008, 10:08 PM
你B
Its only a column of dust

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Les, I believe I might have seen some detail in NGC 3918 at 707x with my 12" reflector, although I'm not certain - may have been the seeing (it was great on the night in question) but it is something I really want to chase up.

Tomorrow is a day off, so I'll be out in the morning with the 10" - hoping for great seeing...
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Old 05-03-2008, 02:37 PM
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goober (Doug)
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Quote:
Originally Posted by ngcles View Post
Interested in your impressions of NGC 3766 -- you saw 2 orange stars which is pretty much what I'd expect in the 4". With 8-10" there is third one. Two are close together on the NW side of the cluster and the third is just to the east of centre. All three are M0 Iab supergiants. The three are pretty easy to see in 10" and make the white stars look a bit "icy" by contrast. Must take a look next time to see if I can see the "W". This cluster truly is one of the rarely mentioned gems of the southern sky that if transplanted to say Cassiopeia, we'd never hear the end of ...
Cheers Les, if you hadn't mentioned it in the latest AS&T, I wouldn't have tracked it down.

The "W" jumped right out at me, but that was because the of orientation of the scope. Others may see a "M", or Greek Sigma character "Σ". The two orange stars were at the bottom and top of the last part of the "W" ... i.e. "/".
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