Sky & Telescope - February 2021 - 29

POSS-II / STSCI / CA LTECH / PA LO M A R OBSERVATORY

After taking in Nu and Co., I shifted southeastward, past
NGC 2169, along a ragged star chain to a slender parallelogram of 7th- to 9th-magnitude stars, measuring 8′ by 2′,
oriented east-west. Something blurry at the parallelogram's
western end caught my eye. Briefly upping to 100× clarified
it as a dim double star of approximately 20″ separation. I'd
have thought such an obvious duet would warrant an entry
in the Washington Double Star Catalogue - but it doesn't.
Returning to 20×, I hopped northward to Xi Orionis, then
veered northeastward through a shorter chain to a narrower
parallelogram. Its brightest member is a legit binary - called
Σ877, it displays 7.6- and 8.0-magnitude stars 5.7″ apart. The
petite pairing resolved cleanly at 100×.
No telescope? No problem. Binocular users will love the
broader 37 region. Starting at NGC 2169, I casually scanned
the abovementioned ragged star chain hand-holding my
7×50s. I kept going, since the chain curved eastward in a
gentle arc of 6th- and 7th-magnitude stars. The fourth star
in this extended section, a variable identified as HD 44033,
exuded a strongly orange sheen. East of it, the stronger variable BL Orionis (magnitude range 5.9 to 6.6) glowed rosyred in the binocs.
Just south of that graceful array of stars are three
binocular doubles. OSS 73 features 6.9- and 7.7-magnitude stars, 72″ apart, aiming at 5th-magnitude
73 Orionis to the southwest. A pair exhibiting
6.7- and 7.4-magnitude stars 189″ apart -
HD 43873 and HD 43840, respectively -
points close to 74 Orionis. Finally, southwest of 74 Orionis, OSS 71 consists
of 7.2- and 7.6-magnitude stars 90″
apart. The binoculars framed all three
generously separated sets in one field
of view. In the refractor, the components shone various shades of white,
blue, and orange.
In sky lore, Nu and Xi Orionis
correspond more-or-less to where
the Hunter clutches his club. This
sector of the constellation is not
in the same league as the famous
Sword of Orion, but it offers lots of
pretty celestial scenery for low-power
looking. I suggest you scan slowly,
using your binoculars or a wide-field
scope, all the way from Nu Orionis to
BL Orionis - and don't miss those colorful doubles to the south.

The nebula is often incorrectly designated NGC 2174.
S&T former contributing editor Sue French has reported that
NGC 2174 is a prominent knot in the northwestern part of
the sprawling nebula. Sue has stated there doesn't appear
to be an obvious concentration of stars within NGC 2175,
though " clumps of stars loosely scattered across most of the
nebula " might be Collinder 84, an obscure cluster suggested
by Swedish astronomer Per Collinder in 1931.
My route to NGC 2175 followed a sequence of stellar
steppingstones of increasingly fainter magnitude, starting at
a quadrilateral-shaped asterism, 2¼° by ½° in extent, outlined by the 4th- to 6th-magnitude stars Chi1 (χ), Chi 2, 57,
and 64 Orionis. After placing 4.6-magnitude χ2 Orionis in
the crosshairs of my fi nderscope, I star-hopped northward to
T CLUSTER CREATURE At a distance of almost 8,700 light-years, the
open cluster NGC 2194 isn't a conspicuous object in backyard telescopes. However, this fairly rich cluster displays subtle character in the
form of a body and tail. The string of faint stars forming the tail is visible
in mid-size suburban scopes at medium to high magnification.

NGC 2194

Dim and Mysterious
Engaging my 10-inch Dobsonian once more, I
advanced to the top of Orion's club. Way up there is
NGC 2175, an emission nebula associated with an open
cluster. Both objects are usually misidentified on charts -
my trusty Uranometria included.
sk yandtelescope.org * FEBRUARY 2 021

29


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Sky & Telescope - February 2021

Table of Contents for the Digital Edition of Sky & Telescope - February 2021

Contents
Sky & Telescope - February 2021 - Cover1
Sky & Telescope - February 2021 - Cover2
Sky & Telescope - February 2021 - 1
Sky & Telescope - February 2021 - Contents
Sky & Telescope - February 2021 - 3
Sky & Telescope - February 2021 - 4
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