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(IAAC) Obj: ngc 7009 (Saturn nebula) - Inst: 20" f/5 dob newt
Observer: Lew Gramer
Your skills: Intermediate
Date and UT of Observation: 1997-07-5/6, 06:30 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, OIII
Object: ngc 7009 (Saturn nebula)
Category: Planetary nebula [4+6]
Constellation: Aqr
Data: mag 8.3 (star 11.5) size 28"x23" (halo 2'?)
RA/DE: 21h04m -11o22m
Description:
Bright and very easily found by sweeping W of nu Aqr (which is
the bright canaryish star due N of the "V" in the backbone of
Capricorn the goat.) Without a filter, this bizarre planetary
actually appeared YELLOWISH at 70x, with clear elongation E-W.
At 210x, the elongated disk seen at lower power actually breaks
into a separately elongated disk (E-W), and two short faintish
"knobs" on the ENE and WSW edges of the disk. Otherwise a near-
featureless, bright yellow-green blob. With an OIII filter, the
ansae actually seem *shorter*, while the disk appears slightly
larger and even more strongly elongated. The N side of the disk
face, well above the ansae, appears somewhat brighter, with a
slight mottling intermittently visible. At 420x with the OIII,
the ansae look essentially unchanged, with the core showing a
confirmed darkening N, and some mottling S. Suddenly however,
a faint, very irregular halo becomes visible to averted vision,
stretching perhaps 2' NE, 2' S, and less than 1' in most other
directions from the bright inner disk. With concentration, this
halo seemed like it COULD show more detail, especially at higher
power. Both halo and core may also be worth a try with a UHC...
[Telescope limiting magnitude was found using the Luginbuhl &
Skiff _OH_ photometric data for ngc 6802 in Vulpecula - handy!]