(IAAC) Obj: Jonckherre 320 - Inst: 17" f/15 classical Cassegrain equatorial mount


Observer: Dave Mitsky
Your skills: Intermediate (some years)
Date/time of observation: 1998/12/15 07:18 UT
Location of site: ASH Naylor Observatory, Lewisberry, PA, USA (Lat 40.15 d N, 76.9 d W, Elev 390 m)
Site classification: Exurban
Sky darkness: 5.0 <Limiting magnitude>
Seeing: 6 <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): O-III
Object(s): Jonckherre 320
Category: Planetary nebula.
Constellation: Orion
Data: mag 11.8  size 7"
Position: RA 05:05.6  DEC 10:42

One of the many deep-sky objects that I observed on this occasion was the tiny 
planetary nebula Jonckherre 320.  This 7" diameter object was difficult to 
distinguish from nearby field stars at moderate magnification (118x) without 
the use of the nebula filter "blinking technique".  J320 appeared nonstellar 
(albeit as just a small, circular, colorless, and high surface brightness glow)
at higher magnifications, although the use of the O-III filter was a definite 
plus.  J320 and J900, another planetary nebula that I had observed previously, 
are featured on page 80 of the January 1999 Astronomy. 
Optional related URLs: http://www.msd.org/obs.htm
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