The Caldwell Objects

230 billion Suns and a physical diameter of
nearly 120,000 light-years. NGC 7479 is 50
percent larger than NGC 7814 and about 20
percent larger than our Milky Way.
Part of the beauty of space is that we can look
out upon the galaxies and see them at various
angles to our line of sight. It's like looking at a
snapshot of a room full of people waltzing in a
circle; in such a photograph we can see all kinds
of bodies at all kinds of angles. Our "snapshot" of
NGC 7814, for example, shows a nonbarred spiral
almost exactly edge on, while that of NGC 7479
shows
a barred spiral halfway between edge on and face
on. When we look at long-exposure photographs
of NGC 7479 our gaze is immediately drawn to
the galaxy's marked asymmetry. The dominant
feature of its backward S form is a long, bright
bar, which runs roughly north and south from
the galaxy's central pip. The galaxy's two
brightest arms are feebler extensions of the bar
that look like stretched strands of taffy. The
westward-curving spiral arm appears sharply
defined, while the other arm looks flocculent, like
frayed rope. One recent analysis of NGC 7479's
gas dynamics implies that the dominant spiral
arm is inclined to the
43 & 44
galaxy's main plane. This suggests the spiral was
tidally disturbed when a small satellite system
merged with it. Such a merger might also
account for the galaxy's long bar and its peculiar
dust lanes, which rip through the bar like
dissection marks made by a nervous student in
an anatomy class. Feathery extensions of dust
and gas also trickle off concentric regions of star
formation on either side of the bar, and they fill
in the otherwise dusty void with a mist of
starlight.
The galaxy is a fine sight in small telescopes
but requires much patience. At 23x in the 4-inch
NGC 7479 first appears as a very faint lensshaped
object, like a poorly erased pencil mark.
But with a prolonged gaze, the galaxy's bar
gradually materializes out of the haze like a
white-robed figure approaching through a fog. In
moments of fine seeing the galaxy seems to
become transformed magically from a spindle of
light to a pale cat's eye with a bright, vertical slit.
I later discovered that my experiences with the 4inch
Genesis mimicked what Adm. William
Henry Smyth perceived in 1830 through his 5.9inch
Tully refractor. In his Cycle of Celestial Objects
Smyth describes NGC 7479 as being "very faint;
but after long gazing under clock-work motion, it
comes up, trending very nearly north and south,
having a telescopic star at each extreme." John
Herschel's 20-foot reflector revealed the galaxy as
little more than a streak tapered at each end.
With his view and Herschel's in mind, Smyth
made the following deduction: "Now, the sphere
being the general figure assumed in consequence
of the particles mutually attracting each other, we
can only suppose that the lenticular appearance
before us, is a vast ring [of stars] lying obliquely
to our line of vision."
Smyth was not totally off his rocker box.
John Herschel's father, William, had discovered
many nebulous objects that revealed themselves
The Caldwell Objects 177