Sky & Telescope - December 2022 - 27

HDW 2: DALTON WILSON; IC 289: ADAM BLOCK / MOUNT LEMMON SKYCENTER / UNIVERSITY OF ARIZONA
Theodore Gull (all at the Goddard Space Flight Center at the
time) found it while scouring images from a 1979 emissionline
survey of the galactic plane that Robert Parker of the
Johnson Space Center conducted with his colleagues.
To reach our next target, find Trumpler 3 again and scan
less than 0.5° south for a short arc of several 11th- to 13thmagnitude
stars. The first time I sought HDW 2 was just a
year ago, when I turned my 10-inch its way using 94× and
an O III filter. I was a bit surprised to notice a large, subtle
glow encompassing the group of stars. Previously, I had only
read of former S&T Contributing Editor Sue French's sighting
(S&T: Dec. 2015, p. 50) with a 15-inch reflector.
On a whim, due to how the planetary seemed to fill the
field more than I liked, I also looked for it in my 5.1-inch.
Then came an even bigger surprise. At 34× with a narrowband
filter, a soft glow blossomed out from around those
stars as I swept over the field. Increasing the magnification to
59× settled my doubts because the glow was 5′ across, round,
and readily evident.
HDW 2 also goes by the designation Sh 2-200, as Sharpless
included it in his second Catalogue of H II Regions published in
1959. But it was Austrian astronomers Herbert Hartl, Johann
Dengel, and Ronald Weinberger who, more than 20 years
later, classified it as a planetary nebula after rediscovering it
while inspecting POSS red plates.
Our final target is the only planetary in Cassiopeia discovered
visually. The famed New York comet hunter Lewis Swift
spotted IC 289 in September 1888 using a 16-inch refractor.
To find it, look just shy of 2° south of Trumpler 3 for a
10.1-magnitude star (BD+60 631).
With my 5.1-inch at 59× and using moderately averted
vision, the planetary is visible as a faint disk almost 2′ north
of the star. At 94× in my 10-inch, its 35″-wide disk is visible
with direct vision, while an O III filter gives a decent boost
in contrast. At 260×, its disk is almost perfectly round and of
even surface brightness.
And with that, we conclude our tour. But let me leave you
with this thought: While planetary nebulae are short-lived on
an astronomical timeline, the reason we can see so many is
because the Milky Way is so vast. Some of those that we see
today actually lie far enough away that they've already faded
away. Just another reason to savor every one.
¢ SCOTT HARRINGTON owes a debt of gratitude to planetary
hunter Kent Wallace for his massive tome Visual Observations
of Planetary Nebulae, which he first self-published in 2017.
FINDER CHARTS: Go to https://is.gd/Cas_PNe for deeper
finder charts of these targets.
FURTHER MATERIAL: For a truly inspiring and massive slate of
high-quality planetary nebula drawings, visit Uwe Glahn's webpage
at https://www.deepsky-visuell.de.
You can purchase Wallace's book at webbdeepsky.com/publications/books.
LAST
BUT NOT LEAST A 10th-magnitude star points the way to
IC 289. Following Lewis Swift's discovery, Edwin Hubble was the first
to classify the object as a planetary nebula.
ACCOMPANIED BY AN ARC A pretty semicircle of stars adorns
HDW 2's nebulosity, its 16th-magnitude central star a mere speck
among them. In photos, HDW 2 has a striated appearance, earning it
the nickname the Bearclaw Nebula.
sk yand tele scope .o r g * DECEMBER 2022 27
https://www.is.gd/Cas_PNe http://www.deepsky-visuell.de/ http://www.webbdeepsky.com/publications/books http://www.webbdeepsky.com/publications/books https://skyandtelescope.org/
Sky & Telescope - December 2022

Table of Contents for the Digital Edition of Sky & Telescope - December 2022
