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Planetary
Nebula
aka "The Eye", NGC 3242, PN G261.0+32.0, PK
261+32.1, ARO 4, ESO 568-5
RA: 10h24m46.1s, Dec: -18°38'32" (2000) in Hydra
Magnitude: 8.60
Size: 25"
Mean
Surface Br. 15.3 Mag/arc-secē
Distance:
2800 ly
Minimum
requirements to detect: any telescope under urban skies |
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 The
Ghost of Jupiter is one of the finest planetary nebulae for any size
telescope, and one of the most observed non-Messier's. This
object was discovered by William Herschel in 1785.
In a small telescope it
appears as small, oval disk that bears a close resemblance to
Jupiter (hence the name). It was H. Smyth who first noted this
resemblance. Like most bright planetary nebulae, the Ghost
appears pale blue or green to the eyes of most observers.
In my 6-inch it appears
as an oblong disc of unusually high surface brightness and sharp,
well defined edges.
For those with access to
larger-aperture instruments, NGC 3242 has an abundance of delightful
detail in store. Burnham wrote, "There is a bright,
strongly elliptical inner ring which strikingly resembles the
outline of a human eye; this feature measures 26" x 16"
and is oriented southeast to northwest." The central star
is about 12th magnitude and sits right at the center of the
elongated inner ring, completing the "Eye", another
apt name for this wonderful object. The HST image at the top
of the page shows this inner ring quite well. Of course, don't
expect this level of detail in the eyepiece!
I observed NGC 3242 in
my 18-inch Dob in February 2000. Here are my notes from that
session:
At 425x The Ghost took on
an appearance quite similar to that of NGC 1535 (Cleopatra's Eye)
and NGC 2392 (The Eskimo). Once again I found myself looking
at a large oval with a bright, elongated ring surrounding the
central star. I'm always struck by how sharp the outer edges
of this one are. The surface brightness of this planetary is
higher than the other two; the inner-ring detail was not quite as
obvious as that of NGC 1535, but much more easily visible than
that of the Eskimo. This is one of those objects worth
returning to again and again, regardless of the instrument.
According to David Knisely
The Ghost is shows a large improvement using UHC and OIII filters.
For the UHC he finds "much higher contrast with faint circular
outer halo-like shell beyond the two inner shells now visible."
And for the OIII, "much darker background but the two
inner shells really blaze out."
This image from the DSS shows a 20' x' 20' field. North is down
and east is to the right.
The view in a 6-inch at 50x. North is down, east is right.
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