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(IAAC) Obj: ngc 6703, ngc 6702 - Inst: 20" f/5 dob newt



Observer: Lew Gramer
Your skills: Intermediate
Date and UT of Observation: 1997-07-5/6, 05:30 UT
Location: Savoy, MA, USA (42N, elev 700m)
Site classification: rural
Limiting magnitude: 7.3 (zenith), 16.5+ (20", 210x)
Seeing: 3 of 10 - pretty good
Moon up: no
Instrument: 20" f/5 Tectron truss-tube dob Newtonian reflector
Magnification: 70x, 210x, 420x
Filters used: None
Object: ngc 6703, ngc 6702
Category: Non-interacting Galaxies [SA0-, E3:]
Constellation: Lyr
Data: mags 11.3, 12.2  sizes 2.5'x2.3, 1.8'x1.3'
RA/DE: 18h47m  +45o40m
Description:
n6703, the brighter of this unusual pair of galaxies in Lyra,
was surprisingly bright at 70x, with little detail. n6702 was
found with some difficulty S of n6703, in the same 55' field.
Averted vision was helpful in locating it amid the myriad field
stars. At 210x, the diffuse halo of n6703 brightened rapidly to
a bright core, which appeared to show a good-size "dust lane"
or dark ark about 1' S of its center. n6702 was still barely
visible in the same 20' field, making for easy comparison. It
was roughly the same size as n6703. But unlike its putative
partner, 6702 showed a quite elongated halo (ENE-WSW), with the
elongation especially apparent in its moderately brighter core.
At 420x, the "dark lane" in n6703's core disappears! Instead,
the core at higher power appears slightly elongated NE-SW, with
a mag. 13 star involved just on the S edge of the halo. Total
apparent size about 2.5'x2'. n6702 actually seems fainter at
410x, with the bright core LESS apparent. Total size 2'x1'.
It's interesting to observe the unusual: open clusters in Peg,
planetaries in Vir, or in this case, bright galaxies in Lyr!
[Telescope limiting magnitude was found using Luginbuhl and
Skiff's photometric data for ngc 6802 in Vulpecula - handy!]