(IAAC) Obj: NGC 3631 - Inst: 17" f/15 classical Cassegrain equatorial mount


Observer: Dave Mitsky
Your skills: Advanced (many years)
Date/time of observation: 2001/4/19 03:01 UT
Location of site: ASH Naylor Observatory, Lewisberry, PA, USA (Lat 40.15 d N, 76.9 d W, Elev 190 meters)
Site classification: Exurban
Sky darkness: ~5.0 <Limiting magnitude>
Seeing: 5 <1-10 Seeing Scale (10 best)>
Moon presence: None - moon not in sky
Instrument: 17" f/15 classical Cassegrain equatorial mount
Magnification: 118, 144, 202, 259x
Filter(s): None
Object(s): NGC 3631
Category: External galaxy.
Class: SA(s)c I-II spiral galaxy
Constellation: Ursa Major
Data: mag 10.4  size 5.5'x4.6'
Position: RA 11h:21m  DEC 53d:10'
After observing Comet C/2001 A2 (LINEAR) and other celestial objects I set the 
shutter of the French Dome for an overhead view.  M97 (118x) was quite faint in 
the less than transparent sky.  I had to play hide and seek with clouds for a 
bit but eventually I tracked down another new Herschel 400 galaxy, one that is 
located about 2 degrees southeast of M97.  NGC 3631 is a moderately large star 
city of the SA(s)c I-II variety.  According to the NSOG this face-on 10.4 
magnitude spiral galaxy is 5.5'x4.6' in size and has a surface brightness of 
13.8 magnitude.  It was dimmer than it should have been due to the poor 
transparency and local light pollution but I could see a circular glow with a 
slightly brighter core.  As with the comet the 32mm U.O. Koenig-II (202x) 
provided the best view.
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