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Re: (IAAC) Obj: M1 Crab Nebula - Inst: 12.5" F-4.8 dobsonian
"William L. Schart" wrote:
>
> Paul:
>
> M1 was a very difficult object for me too. I fianlly spotted it last
> year in my C8, but under somewhat better conditions than yours (no
> Moon). I use DSCs, so finding the position was problem, just seeing the
> darn thing: it was the faintest of grey smudges, verified by jiggling
> the scope - it moved along with the stars.
Just to add to the mix, here's my record of my first M1
observation from my home in Tully, NY (15 miles s. of
Syracuse in Central NY): 76.12w, 42.47n; el. c. 1550'.
(Quoted passages are my exact words ... I use a casette
recorder for my descriptions.).
**BTW, I am always uncertain about the term "seeing" ... any
guidelines appreciated. I usually make two obervations
(naked-eye and at 70.5x), but seem come up with some pretty
optimistic estimates while others' seeing numbers tend to be
lower. OTOH, maybe I'm only going out on the best nights. :-)
---
Instrument: Orion SkyQuest XT-8: 8" (203mm) Dob., fl. 1200 mm.
Sept. 29: 1:45 - 3:20AM EDT: "it's gotten darker ... crystal
clear"; some twinkle naked-eye (Capella, Aldebaran), little
twinkle at 70.5 (seeing 9.0-9.5); all UMi dipper stars
visible: lim. mag. 5.5 +; breeze; temp. 41° --> 40°
M1:
37.5x: "fuzzy spot ... in a lopsided triangle of stars,"
other field stars, object is "non-descript, oblongish,
uniformly grey, smudgy, ovalish"
70.5x: bigger but no structure, "mottled toward center,"
oval seems flattened in an e-w direction, compressed n-s
96.8x: "perhaps more of a fuzzy, light detailing toward the
middle," mottling (?), raggedness toward edged, elongated e-w
133x: suggestion of a mottled appearance, av: faint
raggedness, toward e more elongated than to w; e edge seem
to have "raggedy extensions of light material ... a faint
smudge elongated in an e-w direction"
---
John McMahon
Tully, NY
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