Sky and Telescope - March 2017 - 34

Binocular Tour

NGC 2353

M50

2 NGC 2353 lies about 3,400 light-years away. The open cluster
appears a bit bottom heavy, with the brightest stars in its lower half.
Look for 7th-magnitude HD 55879 near the cluster's southern edge.

2 Charles Messier discovered open cluster M50 in 1772, but it was
probably detected in 1711 by Giovanni Domenico Cassini. M50 looks
like a patch of fog in small binoculars, an appearance that caused many
18th-century observers to (erroneously) conclude that the cluster was
surrounded with nebulosity.

Object

Mag(v)

Size

RA

Dec.

NGC 2360

7.2

14.0′

07h 17.7m

-15° 39′

NGC 2343

6.7

5.0′

07h 08.1m

-10° 37′

NGC 2353

7.1

18.0′

07h 14.5m

-10° 16′

M50

5.9

15.0′

07h 02.8m

-08° 23′

NGC 2215

8.4

11.0′

06h 20.8m

-07° 17′

NGC 2232

4.2

45.0′

06h 28.0m

-04° 51′

Fertile Crescent

-

3.0°

06h 28.0 m

+00° 00′

NGC 2301

6.0

15.0′

06h 51.8m

+00° 28′

NGC 2244

4.8

30.0′

06h 32.3m

+04° 51′

Rosette Nebula

9.0

1.3°

06h 31.4m

+04° 58′

Cr 97

5.4

25.0′

06h 31.0m

+05° 50′

Cr 106

4.6

35.0′

06h 37.1m

+05° 58′

Cr 107

5.1

30.0′

06h 37.7m

+04° 45′

NGC 2264

4.1

40.0′

06h 41.0m

+09° 54′

NGC 2169

8.7

5.0′

06h 08.4m

+13° 58′

Cr 89

5.7

60.0′

06h 18.0m

+23° 38′

M35

5.1

25.0′

06h 09.0m

+24° 21′

NGC 2158

8.6

5.0′

06h 07.4m

+24° 06′

Angular sizes and separations are from recent catalogs. Visually, an object's
size is often smaller than the cataloged value and varies according to the
aperture and magnification of the viewing instrument. Right ascension and
declination are for equinox 2000.0.

34

M A R C H 2 0 1 7 * SK Y & TELESCOPE

Our next "object" has no name, but it may be the best
view in the entire tour. Five degrees north of NGC 2232,
you'll ﬁnd an arc of bright stars straddling the celestial equator. This group spans just over 3°, from declination +1° north
to -2° south, at 06h 28m RA, and forms an arc that opens to
the west. If this lovely asterism has a name, I haven't found
it yet, so I've taken to calling it the "Fertile Crescent". It's
a perfect match for 70-mm binoculars, ﬁlling half the ﬁeld
with a sea of F main sequence stars and K giants.
Scan 6° east of the Fertile Crescent to pick up NGC 2301. If
I hold my 15×70s very still, I can make out half a dozen stars in
a ragged north-south line. A line of three equally bright stars
1° west of NGC 2301 adds to the charm of this ﬁeld. You'll
deﬁnitely want to revisit this one with a telescope, as more
magniﬁcation will reveal a dense swarm of stars with three
arms sticking out like a letter T. While you're in the neighborhood, go on 4° east to pick up the pretty pairing of Delta (δ)
and 21 Mon, a visual double with a separation of 13′.
Now zig back another 6° to the northwest of NGC 2301 to
ﬁnd a cluster of clusters, including NGC 2244 (Caldwell 50).
NGC 2244 is full of bright young stars, so it looks smashing
even across the intervening 5,200 light-years. The cluster is
outlined by six bright stars in two bent lines, in the shape of
an open book. The brightest stars in NGC 2244 are HD 46223
and HD 46150, both O giants more than 50 times more massive than our Sun, and over 400,000 times brighter.
I'd be remiss if I didn't mention that NGC 2244 is the
cluster embedded in the Rosette Nebula. From the remote
Sonoran Desert I have seen the Rosette Nebula enclose the
cluster like the petals of a rose. Be warned, though, this faint
ﬂower only blooms under dark skies, and it doesn't take much
light pollution to kill it. If you can see the nebula, great, but
if not, don't fret - the ﬁeld offers plenty of wonders besides.

NGC 2353: JIM THO M MES; M50: JOHN BLU M

Objects in the Winter Milky Way
Sky and Telescope - March 2017

Table of Contents for the Digital Edition of Sky and Telescope - March 2017
