The Caldwell Objects

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teurs fail to see the central stars of planetaries
because they fail to use sufficiently high magnification.
A 10-inch telescope should show NGC
3195's central star at magnifications greater than
350x. NGC 3195 has a high surface brightness, so
don't be afraid to crank up the power to more
than 50x for each inch of your telescope's
aperture. The way to detect the faint central stars
of planetary nebulae is to use power, lots of
power. The drawing on the previous page shows
the nebula as I saw it under moderate
magnification through the 20-inch, without the
central star.
The Hubble Space Telescope transformed
NGC 3195's seemingly uniform glow into an
irregular array of coiled nebulosity. Under HST's
gaze the inner annulus appears to be made of
two loops seen at an oblique angle; it looks more
like a tilted hourglass than a ring. The outer
envelope may be two expanding bubbles
traveling in opposite directions. Spectroscopy has
revealed that the planetary is approaching us at a
speed of about 16 km per second while the
nebulosity expands at a speed of about 40 km per
second. The expanding shell has about 9 percent
as much mass as our Sun and extends about one
light-year, which makes it similar in size to NGC
2392 (Caldwell 39), the famous Eskimo Nebula in
Gemini.
Just 30' northwest of NGC 3195 is the little
enigmatic galaxy NGC 3149. Its NGC description
reads: "Faint, small, little extended, very little
brighter in the middle, star of 15th magnitude
involved." But what's enigmatic is that some star
charts and field guides fail to recognize the
galaxy's very existence. Not that it isn't there. It
is. But the second edition of Sky Catalogue2000.0
does not include it, nor does the Deep Sky Field
Guide. It is not plotted in the first edition of
WilTirion's Sky Atlas 2000.0, nor does it appear in
Uranometria 2000.0.
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Modern atlases, such as the Millennium Star Atlas
and the second edition of Sky Atlas 2000.0, do
include it. The galaxy shines at magnitude 13.1
and is visible in an 8-inch telescope as a timid
circular patch of light 2' across.
Before leaving Chamaeleon, take a moment to
contemplate the South Celestial Pole a mere fist's
width away. Where exactly is the Pole? Sadly, the
southern sky lacks a conspicuous pole star. The
closest reasonably bright star to it is Sigma (σ)
Octantis, which lay just 1° 03' from the pole as
the year 2000 began. This magnitude-5.5 star
certainly is not a retina burner, however, nor a
guiding light. No wonder so many people
throughout the ages have sung the praises of
Polaris; with a glance voyagers in the Northern
Hemisphere can sense its comforting light and
orient themselves. But this sense of security
vanishes when one ventures south of the
equator. Looking toward the South Celestial
Pole, I feel as if I'm peering down a dark alley,
and though I know where I'm looking, I see no
guiding light, only a void. The
Deep-Sky Companions: The Caldwell Objects