Sky & Telescope - January 2025 - 55

Suburban Stargazer by Ken Hewitt-White
A Collection of Clusters
These modest deep-sky treasures in eastern Taurus are within range of backyard telescopes.
T
aurus ain't no slouch. The big
bad Bull is home to the Pleiades
and Hyades clusters, the famous Crab
Nebula supernova remnant, and the red
giant Aldebaran. Gleaming at magnitude
+0.9, Aldebaran is the ninth-brightest
star visible to mid-northern observers.
There's subtler stuff, too. For example,
the region east of Aldebaran holds a
quartet of relatively obscure yet enjoyable
open clusters. On a windy evening
last January, I looped around the area
using an 8-inch f/6 Newtonian reflector
on a Dobsonian mount. Although
my suburban night sky is the color of
neglected dishwater, all four clusters -
and more - showed in my trusty Dob.
Join me on a wind-chilled tour.
Ugly Ducklings
My Taurus loop begins at Aldebaran,
Alpha (α) Tauri. Aldebaran dominates
the Hyades Cluster, whose loosely bound
members are about 150 light-years from
Earth. One caveat: Aldebaran isn't a
member. Only 67 light-years away, the
red giant is an older sun that lies in the
same line-of-sight as the mostly youthful
Hyades. But don't let the details of
distance blunt your appreciation of this
gorgeous star's fiery gleam.
Next, I examined NGC 1807 and
NGC 1817, side-by-side clusters aligned
northeast-southwest. The sparse
specimens reside 8½° east of Aldebaran,
on the western flank of the Milky
Way, just north of Taurus's border with
Orion. If my 8-inch reflector had been
on an equatorial mount, I could've
shifted the scope directly eastward
from Aldebaran to the clusters. Instead,
my star-hop isn't quite so direct - the
route from the star dips briefly into
Orion before returning to Taurus - but
the circuitous path is illuminated by
finderscope-friendly 4th- and 5th-magnitude
stellar stepping-stones.
The first two are Sigma1 (σ1) and
Sigma2 (σ2) Tauri, which stand 7.3′
apart, 1° southeast of Aldebaran. After
the Sigma set, I continued southeastward
3½° to Omicron1 (ο1) Orionis,
then a bit more than 1° to Omicron2
(ο2). At ο2, I turned northeastward
for 23/4° to 11 Orionis - " 11 " being
the star's identification in the Historia
Coelestis Britannica compiled in the
early 1700s by British astronomer John
Flamsteed. Veering east-northeastward
from there, a 1¼° hop landed me on
another Flamsteed, 15 Orionis. Then
it's a 2
/3° hop northeastward to a
5.2-magnitude, deep-orange dot cataloged
as HD 33554 (oddly, no Flamsteed
designation for this star). One further
step northward took me across the
Orion/Taurus border to the clusters.
Admittedly, NGC 1807 and NGC
1817 are ugly ducklings. The former is
listed at magnitude 7.0, while the latter
is magnitude 7.7. They're 12′ and 20′
in diameter, respectively, and together
span less than 2
/3° of sky. My Dobsonian
at 41× captured both uglies in a single
view, each cluster defined by a northsouth
row of stars. The row in NGC
1807 is a zigzag of six 9th- and 10thmagnitude
stars. Upping to 76× added a
similar number of fainter pinpoints all
around. NGC 1817 managed a zigzag of
just four stars. However, I noticed something
pooled east of the row. At 135× my
averted vision sensed a pale puddle of
stars at the threshold of visibility. Hey,
not so ugly after all.
A Flock of Flamsteeds
A celestial atlas is a wonderful thing.
As I examined various charts of eastern
Taurus for easy routes to the clusters, I
" discovered " a large pattern of stars -
not visible to my bare suburban eyes but
bright in my 8×50 finderscope - a few
pBULLISH ON CLUSTERS The constellation Taurus, the Bull, offers backyard astronomers lots
of open star clusters. Although the brilliant Pleiades (M45) and Hyades clusters are fan favorites,
several smaller starry collections in eastern Taurus are also worth a look. The brightest object in
this photo is the planet Jupiter, which visits Taurus in roughly 12-year intervals. This month, the
planet is slightly farther east than it was when captured in this photo from January 2013.
sk yand tele scope .o r g * JANUARY 2025 55
ALAN DYER

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Sky & Telescope - January 2025

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