(IAAC) Obj: M22 - Inst: 12.5" Binocular Telescope

Observer: Dan Duriscoe
Your skills: Advanced (many years)
Date/time of observation: July 23, 2000 1130 PDT
Location of site: Pinehurst, CA (Lat 36 N, Elev 4000')
Site classification: Rural
Sky darkness: 6.0 <Limiting magnitude>
Seeing: 8 <1-10 Seeing Scale (10 best)>
Moon presence: None - moon not in sky
Instrument: 12.5" Binocular Telescope
Magnification: 74
Object(s): M22
Category: Globular cluster.
Constellation: Sgr
Data: mag   size 
Position: RA :  DEC :
This great globular was seen with tremendous depth and richness with
the binocular telescope.  It does not appear spherical, but the
optical illusion of depth produces a pronounced 3D effect where faint
stars appear further away than dimmer ones.  Also, the tremendous
variation in brightness of stars (resolved to the center) is what
gives this cluster its unique appeal. The shape is somewhat wedge-like
with arrow pointing up (north) in this view with Amici prisms that is
right reading right side up, as two dark bands seem to form a chevron
pattern on the north side of the cluster.  In actuality, it may be due
to a dirth of brighter stars in these areas as the richness of fainter
stars is maintained throughout the "bands".  The relative steadiness
of air was a big plus this night as the sky was not particularly dark
or transparent.  Really something!  Views like this make all the work
involved in building large binoculars worthwhile.
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