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RussL
professor emeritus
Reged: 03/18/08
Posts: 745
Loc: Cayce, SC
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Quote:
I know the configuration about which you speak. It's about 2" below the center on my chart. It points to the right on the chart. It could be described as the Hyades. I call it Cepheus.
Hi Ed,
Ah, yes, I see that. After my post last night I found a photo in my Audubon book that clearly showed that shape, although I noticed that it was quite a close in view of the cluster, the entire area of the photo being only about one-fourth the size of your chart. Now that I see the Hyades/Cepheus shape on the chart, it gives me some idea as to the field in which I was trying to count stars. Perhaps I can count more than I thought. I now have a printed copy of the chart and will try again, chart in hand, to see what results I get.
I can also see why you could call the shape Cepheus. 
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"Akita mani yo." Observe everything as you walk. (--Lakota)
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Rich N
Post Laureate
Reged: 09/22/04
Posts: 4923
Loc: San Francisco Bay Area, Calif...
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Thanks, Ed!
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alessandro71
member
Reged: 09/04/07
Posts: 95
Loc: Rho (Milan - Italy)
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site 45°31'N - 9°02'E
date and local time 8 may - 22:00
bad seeing (night sky badly polluted, light and haze)
11x56 (oberw.) mounted
M44, between Asellus Australis-Boraelis easy spotted / counted 17 stars.
Around that, I barely saw 9 other stars
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alessandro
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Randy Cordell
super member
Reged: 09/16/07
Posts: 196
Loc: Cedar Rapids IA
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Hi Ed,
I finally got a sky I could work with in conjunction with a non-work night. Whoo-HOO! So, based on your chart for Ursa Minor, I have a Mag 4.3 sky here tonight with a waxing crescent moon of 34% sitting just outside of Cancer. Moderate light pollution and observing from my driveway. I was surprised that the sky would actually be considered mag 4.! I would have expected 3 something. 4 is not good! So thanks for that tool as well.
Okay. So with my mounted GO 15x70's I saw 30 stars within the circle boundary on your chart. I changed to my 7x50's mounted and I saw 25.
The Cephus asterism is obvious. I forgot you mentioned a Cassiopeia and so didn't look for that one. Up this thread where I made reference to a small triangular grouping that I said was in the "center"....that is the three at the peak of Cephus "roof" and not in the center at all.
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Randy Cordell
Meade StarFinder 10" F/4.7 Dob, Telrad, Craford, Fans
Bogen 3040 and 3050 Tripods with Orion Paragon-Plus Parallelogram or 3047 head
Oberwerk Mariner 7x50
Pentax PCF WP 8x40
Garrett Optical Gemini 15x70 WP-IF
Laptop running Kubuntu and Stellarium 0.9.1
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EdZ
Professor EdZ
Reged: 02/15/02
Posts: 11725
Loc: Cumberland, R I , USA42N71.4W
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Sky magnitude can vary considerably from one direction in the sky to another. I would expect the area of sky near a moon to be considerably brighter than the area near the Little Dipper.
I actually have a few stars labled on almost every one of my star chart pages, so I can get an idea of the sky in the vicinity of my observation.
When sky is fairly dark mag5, I'm seeing about 40-45 stars in 7x50s. Alsmost twice as many with a 15x70.
There is a small triangle with two bright stars, almost dead center.
Cassiopeia is upside down in the upper left quadrant. it can't bee seen in low powered binoculars. In fact to see the entire asterism needs mag 5.4 skies and 25x100 or better.
edz
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Teach a kid something today. The feeling you'll get is one of life's greatest rewards.
member#21
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Randy Cordell
super member
Reged: 09/16/07
Posts: 196
Loc: Cedar Rapids IA
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Edz,
What do you do with the stars that straddle the border of your chart?
Last night I counted 43 in my 15x70's and 34 in both my Pentax 8x40 and OB Mariner 7x50. Skies were 5.6 based on the Polaris LM chart. This is much lower than your count (on the same instrument in one case) under lessor skies. There are stars that I think I see pop in but then I can never quite see them again, even averted, so it's hard to count. But it's fun trying. I'm getting the hang of the borders of your chart.
Also, what is the source of boundaries of clusters like this?
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Randy Cordell
Meade StarFinder 10" F/4.7 Dob, Telrad, Craford, Fans
Bogen 3040 and 3050 Tripods with Orion Paragon-Plus Parallelogram or 3047 head
Oberwerk Mariner 7x50
Pentax PCF WP 8x40
Garrett Optical Gemini 15x70 WP-IF
Laptop running Kubuntu and Stellarium 0.9.1
Edited by Randy Cordell (05/22/08 12:16 PM)
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EdZ
Professor EdZ
Reged: 02/15/02
Posts: 11725
Loc: Cumberland, R I , USA42N71.4W
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Just a bit on your NELM. Just the other night was full moon. I was observing towards the noth and I checked stars in Ursa Minor and could see all the way to mag 5.0. however, behind me in the vicinity of the full moon. best I could see was about mag 4.0.
The NELM reading you want to take should be taken in the vicinity of the object you are viewing. Sky can vary considerably from one region to another.
Straddle stars. If they are inside or on the line, I consider them IN.
BTW, seeing the faintest stars takes considerable effort. In some of the LM studies/counts that I've done, I can count the first 40-50 stars in the first few minutes. I might take 10 minutes to see the last 4-5 stars.
edz
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Teach a kid something today. The feeling you'll get is one of life's greatest rewards.
member#21
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Randy Cordell
super member
Reged: 09/16/07
Posts: 196
Loc: Cedar Rapids IA
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Oh yeah. Good point. Ursa Minor was in nice dark sky much higher than M44. It is hanging low now and for me it's in the glow of a nearby town, not a lot but definately not as dark as Umi.
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Randy Cordell
Meade StarFinder 10" F/4.7 Dob, Telrad, Craford, Fans
Bogen 3040 and 3050 Tripods with Orion Paragon-Plus Parallelogram or 3047 head
Oberwerk Mariner 7x50
Pentax PCF WP 8x40
Garrett Optical Gemini 15x70 WP-IF
Laptop running Kubuntu and Stellarium 0.9.1
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