The Caldwell Objects

esembles Jupiter . . . '" Smyth's full account,
penned in 1837, reads as follows: "A planetary
nebula, pale greyish-white, nearly 2° south of m,
about 20° south-west by west of Regulus, and in
the middle of Hydra's body. From its size,
equable light, and colour, this fine object
resembles Jupiter; and whatever be its nature,
must be of awfully enormous magnitude."
Indeed, today, it's hard not to find a reference to
the Ghost of Jupiter that does not credit Smyth
with at least triggering the idea for the name —
even though he never said "Ghost of Jupiter."
But the time has come to dispel that popular
myth. Smyth was not the first person to draw
attention to NGC 3242's resemblance to Jupiter.
William Herschel, the object's discoverer, did
that. On February 7,1785, he wrote of the object:
"Beautiful, brilliant, planetary disk ill defined,
but uniformly bright, the light of the colour of
Jupiter." Herschel's observation obviously
inspired Smyth to take the analogy one step
further by taking the object's size into
consideration. So it is William Herschel, the
creator of the term "planetary nebula," who
deserves credit for marrying Jupiter and its
"ghost" in our minds.
Now for the million-dollar question: Who
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first coined the moniker Ghost of Jupiter?
Houston didn't. In his May 1969 "Deep-Sky
Wonders" column, he described NGC 3242 as a
"bluish egg." And though Houston mentioned
Smyth's observations in his April 1971 column,
he did not then refer to the planetary as the
Ghost of Jupiter. Indeed, though Houston had
written about NGC 3242 numerous times since
1947, he did not introduce "Ghost of Jupiter"
until his March 1984 column: "W. H. Smyth
mentioned that NGC 3242 is similar in size and
color to the planet Jupiter. Accordingly, it still is
sometimes called the Ghost of Jupiter."
Ernst Hartung does not mention NGC 3242's
popular nickname in his 1968 edition of
Astronomical Objects for Southern Telescopes. James
Mullaney and Wallace McCall include NGC 3242
in their 1978 The Finest Deep-Sky Objects, but they
do not refer to it as the Ghost of Jupiter. And the
moniker does not appear in Volume 2 of the
Webb Society's Deep-Sky Observer's Handbook
(1978). Clearly the name was not in popular use
before 1978. Houston, like others before and after
him, most likely got the name from Volume 2 of
Robert Burnham Jr.'s 1978 Celestial Handbook. Of
NGC 3242 Burnham writes, "In the small telescope
it shows as a pale bluish softly glowing
disc ... appearing like a 'ghost of Jupiter.'" The
mystery would be solved but for one nagging
fact. Burnham, now deceased, placed "ghost of
Jupiter" in quotes, which suggests (but does not
necessarily prove) that someone else had coined
the term. If so, who? For now, that remains a
mystery.
Burnham also wrote that the planetary's
bright inner ring resembles the outline of a
human eye. This has led to the nebula's other
popular nickname, the "Eye Nebula." Arizona
amateur Steve Coe put a more modern spin on it,
saying that through his 17½-inch f/4.5
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