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What's Up Puppis

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#1 asaint



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Posted 11 February 2008 - 07:19 AM

What's Up Puppis

#2 proud uncle

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Posted 12 February 2008 - 01:27 PM

Thanks for the tour, Steve. I was observing Puppis with both binocular and 10" Newt app. one week ago. I saw everything in Steve's article except the second planetary. This region is stunning in binocular. The Milky Way takes on a very nodulous look with all the OC's. I think I identified every one of the OC's in Steve's article using my binocular.

#3 jmcdonald


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Posted 12 February 2008 - 02:42 PM

Thanks Steve. I observed the first 4 objects last night in a 12.5" newt. My notes have an estimate of 25 members for M47; very close to your estimate. It seems there is no way to count them just by one observation because it's hard to discriminate cluster members from background stars. I tried to pick those stars that seemed to stand out and that added to the density of the region compared to the surrounding area. There appears to be another fine double at the west edge with a bright primary and a much dimmer secondary to the north. I think it's Struve 1120: 5.7- and 9.6-magnitude suns separated by 19". Is this what you refer to as KQ Puppis?

M46 is striking because it is so big and so compressed and has so many members resolved. I estimated 150. The involved planetary provides a bonus object and it's a fine object in a good-sized scope with some detail and 2 stars involved.

A question for the forum: are dark lanes in OC's due to dust? Or simply an optical illusion created by lack of stars in certain regions.

Thanks for the great report.

#4 Vic Menard

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Posted 12 February 2008 - 04:04 PM

...A question for the forum: are dark lanes in OC's due to dust? Or simply an optical illusion created by lack of stars in certain regions.

I believe this is an optical illusion--a very pronounced one in NGC7789 which Alex Langoussis has nicknamed "The Jelly Roll!" I was observing NGC2477 in Puppis last week at the WSP and this effect was observed--but not as pronounced as NGC7789 in Cassiopeia.

Another object I always enjoy observing in Puppis is NGC2467. It's another shell being illuminated by a hot Wolf-Rayet star similar to NGC2359 (Thor's Helmet) in Canis Major. NGC2467 is brighter than Thor's Helmet (to my eye), but at -26-degrees declination, it's also about 13-degrees further south. The main shell around the central star doesn't have a clearly defined edge like Thor's, but it responds well to UHC or OIII filters, and in larger apertures, there appears to be another ring attached to it. This secondary ring has given rise to the nickname, "Rita's Ring." I won't go into details, but if you know Rita, you know she has a very large diamond ring--and NGC2467 is reminiscent of a dainty ring with a really big rock!

#5 stevecoe


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Posted 12 February 2008 - 05:47 PM

Vic, Jerel, Kenneth, et al;

I am very glad you enjoyed the tour of Puppis. Lots of great stuff on the Poop Deck.

I agree that the dark lanes that wind through most open clusters are just illusions from places where there are few stars compared to the main body of the cluster. I will ask Brent Archinal the next time I see him.

Steve Coe

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