(IAAC) Obj: M46, M47, NGC2423 - Inst: Celestron 80mm, f/5 refractor, manual EQ mount


Observation Poster: Don Clouse <dlcdeepsky@home.com>

Observer: Don Clouse
Your skills: Intermediate (some years)
Date/time of observation: 2/5/2000, 8:20 pm, eastern
Location of site: Winter Star Party, Florida Keys (Lat 25N, Elev 10 ft)
Site classification: Rural
Sky darkness: 6 <Limiting magnitude>
Seeing: 6 <1-10 Seeing Scale (10 best)>
Moon presence: None - moon not in sky
Instrument: Celestron 80mm, f/5 refractor, manual EQ mount
Magnification: 11x, 27x, 53x
Filter(s): none
Object(s): M46, M47, NGC2423
Category: Open cluster.
Class: 22r, 13m, 22m
Constellation: Pup
Data: mag 6.1, 4.4, 6.7  size 27', 29', 19'
Position: RA 7h:40m  DEC -14:30
At 11x (35mm Ultima, 4.3 degree field of view)all three clusters (M46, M47,and
NGC2423) fit comfortably in the field.  M47 lies 1.3 degrees WNW of M46, while
NGC2423 is 38' N of M47.  (I had estimated the center separations as 2 degrees
and 1 degree respectively.  Ah well.  Practice makes perfect.)  At 11x, M46 was
a wide, diffuse glow with a handfull of tiny stars visible with direct vision.
At 27x, (15mm Panoptic, 2.5 degree f.o.v.) the cluster appeared about 30' in
size.  Two dozen stars were resolved, with direct vision, overlaying a milky
glow.  Many more tiny pin-points popped out with averted vision.  The 
distribution of stars seemed fairly even all the way to the edge of the 
cluster before finally trailing off.  Lovely.  With a 2x Barlow, 50 stars were
visible.  The suggestion of unresolved masses was still there.
For M47 , at 11x, 12 stars were visible with direct vision and several more
with averted vision.  A bright, very open, cluster with widely varying 
magnitudes.  At 27x, M47 appeared roughly circular, about 30' in size, having
about two dozen stars visble with direct vision.  A group of five stars,
including the two brightest, are surrounded by a rough arc open to the NE.  
The overall impression is of several isolated groups of three to six stars.
Very nice.
At 11x, NGC2423 was barely visible as a small, faint glow with one star visible
and the suggestion of a couple more.  At 27x, it appreared about 20' size.
Six to eight stars were visible directly and perhaps 20 with averted vision.
A nice cluster.
At 27x, the entire grouping still fit within the field of view (2.5 degrees).
This grouping makes for a very fine, wide-field, panorama.
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