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milt
sage
Reged: 09/13/04
Posts: 430
Loc: Arizona
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Finally, a clear calm night with temperature a pleasant 70°F. Casper, of course, is the name I gave my Kowa Highlander for its friendly ghost on extremely bright objects. The cross; well, you know the northern cross.
I spent the 1/2hr. of dark adaptation reclined with my old Nikon 12x36D's surveying the area around Cygnus. During my session I consistently counted 10 naked eye stars in the epsilon-eta-gamma Cygni triangle and an 11th and 12th with difficulty, placing NELM about 5.7. The Double-Double was as easy a naked eye split as I can remember.
Switching from 36mm with 60° AFOV to 82mm with 70° AFOV almost takes your breath away. I dove right into EdZ's Cr399 LM chart in Vulpecula and found the mag 11 stars to be solid. E29, E31 and E32 appeared very similar in brightness, proving that Cloudy Night's mag 12.4 for E29 is dead wrong! However, E30 (CN/USNO-A2 mag 12.35) was far more difficult and visible only a third of my tries. Two other stars of similar difficulty not on Ed's chart were mag 12.31 next to S6 and mag 12.43 NW of E6. So I was somewhere in the low 12's, which is consistent with the mid 12's I previously obtained in darker skies.
Enough testing, on to some new objects. Before leaving the Coathanger, I picked up the two nearby open clusters NGC6802 and 6793. I would spend the next two hours in the region between Deneb and M39 (Uranometria L.H. page of chart 32). Deneb was the usual tight white ball in Casper but 2.2° of field just isn't enough to frame the North American Nebula, so I explored its insides. Probably my best view of the night was OC's NGC6997 & 6996 and Dark Nebulae B353 & B352 all in the same field. My wife made the mistake of coming out to say good night around this time and received a lengthy description from the eyepieces.
As I proceeded through the dark lanes and clusters of the Milky Way, I happened on 59 Cygni, a nice 20" double with a ~5 magnitude difference. Then came another nice pairing, rich AV cluster IC1369 and DN B361, followed by a couple more OC's and I was at M39. From there I dropped south and found the curving dark lane B155/6 that leads to the little mag 11.5 planetary IC5117. This 12" PN was definitely stellar at 32x so I folded down one eyecup and blinked my OIII filter to confirm. I found NGC7027 more planetary-like: Bright and busy in averted vision. I bagged 3 more clusters then struck out on a couple as moonrise ended the fun around 11pm (AZ doesn't go on daylight savings time).
Man, I needed that! 
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Clear skies, Milt
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EdZ
Professor EdZ
Reged: 02/15/02
Posts: 12601
Loc: Cumberland, R I , USA42N71.4W
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Thanks for the report Milt.
just checking on this one
Quote:
EdZ's Cr399 LM chart in Vulpecula and found the mag 11 stars to be solid. E29, E31 and E32 appeared very similar in brightness, proving that Cloudy Night's mag 12.4 for E29 is dead wrong! However, E30 (CN/USNO-A2 mag 12.35) was far more difficult and visible only a third of my tries.
E29 is listed on the charts as mag 1184, not 1240. At 1184, it should look very similar to E31 and E32. So, is there an error? Or are you referring to another star?
I was observing this same area last night. I could (with difficulty) see E31 and E32, determined positive ID by the fact that the two I saw stradled the line between E1 and E2. This was with the BT100 at 31x. I could not for the life of me see E30. I've never seen all three in this string at the same time and it can sometimes be difficult to tell which ones are visible. Also I did not see E29.
keep in mind that the spectral class will have a significant impact on the visibility of a star. If the star is towards the red spectrum, it will appear fainter than the listed magnitude. If it is towards the blue spectrum, it will appear brighter than it's listed magnitude. That's why, as you said before, it's good to have a number of targets all around the same magnitude for a variety.
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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Mark9473
Carpal Tunnel
Reged: 07/21/05
Posts: 2703
Loc: 51°N 4°E
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Milt, that's a nice report on a super-interesting part of the sky. Can you be a bit more specific on how NGC 6802 looked? I tried to find it the other night but didn't see it - probably was looking in the wrong place, now that I llok at the Uranometria chart. My Deep Sky Field Guide lists it at mag 8.8, so it shouldn't be that difficult, but the brightest stars are supposed to be mag 12.9.
Have you done any detailed comparisons between Casper and say a pair of 20x80s, with regard to brightness of the sky background? Are there any sky conditions where the Kowa gives so dark a sky background that you think you could do with a bit more light?
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Mark
Leica 8x20; Vixen 8x42; Swift 8.5x44, 10x50 and 20x80; TS 7x50; Orion 15x63
WO Megrez II 80 FD + Baader 90° T2 Amici
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milt
sage
Reged: 09/13/04
Posts: 430
Loc: Arizona
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Quote:
E29 is listed on the charts as mag 1184, not 1240. At 1184, it should look very similar to E31 and E32. So, is there an error? Or are you referring to another star?
No, I was referring to Starry Night having an error on that star's magnitude. Your magnitude seems correct.
Quote:
I could (with difficulty) see E31 and E32, determined positive ID by the fact that the two I saw stradled the line between E1 and E2. This was with the BT100 at 31x. I could not for the life of me see E30.
This agrees with my result. E29, E31 and E32 were all stable in the Highlander but E30 was extremely difficult last night although I did glimpse it at times. I downloaded the Digitized Sky Survey photo of these three (don't know if this link will work outside SN):
http://207.219.21.2/cgi-local/dss.cgi?r=291.802056&d=19.856310&h=10.0&w=10.0&u=P45&v=p452c-EW&p=N65291
E30 shows as two very close but fainter stars. Based on my other limit stars I estimate its visual magnitude at 12.3-12.4.
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keep in mind that the spectral class will have a significant impact on the visibility of a star
Good point, and for others reading focus is critical to seeing the limit stars. I personally find it very difficult to obtain optimum focus using fainter stars so I used Albireo and then moved to the faint ones.
Thanks, Milt
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milt
sage
Reged: 09/13/04
Posts: 430
Loc: Arizona
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Quote:
Can you be a bit more specific on how NGC 6802 looked?
Hi Mark,
Quoting my notes, "A uniform averted vision smear." Although as you said the visual magnitude is 8.8, my Uranometria 2000 Deep Sky Field Guide lists it as having 201 stars with the brightest being mag 14. You may not be able to see it at all in 20x80's without darker skies.
Quote:
Are there any sky conditions where the Kowa gives so dark a sky background that you think you could do with a bit more light?
NO!!! However, there are times when I could do with a bit more field.... Unfortunately, these are mutually exclusive. I agree with other Highlander owners that Kowa hit the sweet spot with the 32x 2.2° ep's. Ask me if I care that the exit pupil is only 2.6mm. 
The ability to resolve point sources, or DSO's made up of separate point sources, improves with magnification. A single star is just a bundle of parallel rays entering the objective that focus to a spot (actually, a diffraction pattern) on the focal plane. Increasing the magnification retains all of the light in this spot while reducing the area of captured background light, making the star appear brighter relative to the background. A higher Strehl ratio (i.e. stuffing more photons into the Airy disk) also makes dim stars appear brighter.
Ed explains this stuff better than I do.
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Clear skies, Milt
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milt
sage
Reged: 09/13/04
Posts: 430
Loc: Arizona
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Quote:
just checking on this one
Quote:
E29, E31 and E32 appeared very similar in brightness, proving that Cloudy Night's mag 12.4 for E29 is dead wrong!
E29 is listed on the charts as mag 1184, not 1240. At 1184, it should look very similar to E31 and E32. So, is there an error? Or are you referring to another star?
Ed, I just realized that I said Cloudy Night's in my original post when I meant to say Starry Night's. Sorry for the confusion.
Milt
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milt
sage
Reged: 09/13/04
Posts: 430
Loc: Arizona
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I spent 3 more hours in Cygnus with my Highlander last night, again enjoying mag 5.7 skies and pleasant temperatures. I only picked up two more Barnard DN's but it turned out to be a Dolidze night, referring to the Do-prefix open clusters catalogued by M.V. Dolidze in 1966. 8/15 objects I confirmed were Do's.
Because of the richness of the Milky Way background, very few of these clusters jump out at you, even in a 32x binocular. The drill is to carefully locate the position and then use averted vision to try to nurse something out of the background. Do10 reminded me of a mini-Hyades; the brightest stars in Do36 formed the number '5', and Do47 was a tight grouping of AV stars around a single bright *.
While in the neighborhood I checked out the Veil and was able to glimpse the division between 6992 & 6995 in the brighter half without any filters. Then I broke my own rule and wasted time trying to bag planetary 6881 without knowing its magnitude. It was 13.9.  I did get mag 10.9 PN 6884, which jumped off the field with an OIII filter.
Probably the best object of the night was OC 6791. Boy, I would have loved to have a look at this one through Mr. Bill's or Ed Jone's giant Fuji's. Through my 82mm Kowa's I saw "a few AV stars resolved against a ghostly round glow." It begs for more aperture. Oh, well.
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Clear skies, Milt
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