Sky & Telescope - January 2025 - 21

I found that M37 is just a touch more noticeable, even
after I factored in the brightness of the 7.3-magnitude star
HD 49009 on the northern edge of NGC 2281. In fact, binoculars
reveal that the only reason NGC 2281 can compete
at all is that its small but brilliant heart far outshines M37's
core. To be fair, though, you need to see both clusters for a
proper comparison.
To find NGC 2281, look about 8° east of 1.9-magnitude
Beta (β) Aurigae until you land among so many Psi (ψ)
Aurigae members that former Sky & Telescope Contributing
Editor Sue French once wondered, " How many Psis can you spy
with your eyes? " (S&T: Feb. 2010, p. 65). The cluster itself can
be spied just 0.8° southwest of 5.0-magnitude Psi7 Aurigae.
Holding my 8×56 binoculars steady, I see an isoscelestriangle-shaped
compact group of stars with a scattering
of fainter suns of similar magnitudes flung around it. This
gives it the appearance of being a much larger and looser
cluster than it actually is. With 12×60s, I can discern a
dozen or so members within the cluster's true diameter,
and while the western tip of the triangle comprises three
stars I can't split them. Peering at the group in my 5.1-inch
reflector at 27× allows me to resolve the tip into a trapezium
of about half a dozen stars and detect a nice orange hue to
HD 49009. More magnification will split the easternmost
member into a pair (magnitudes 9.0 and 10.6, separated
by 8.1″), just like William Herschel did for the first time in
1782 using his 6-inch telescope.
M37 is a snap to find as it lies almost 5° south-southwest
of Theta (θ) Aurigae and in my 8×56s shows hints of graininess
over an otherwise large, smooth glow. Switching to the
12×60s, the cluster now displays partial resolution, while
its northwestern neighbors M36 and M38 show full resolution.
M37's central brightening is irregular in shape and
protrudes eastward. Jumping to my 5.1-inch at 27×, I see the
An Auriga Assortment
Object
Type
NGC 2281
M37
LDN 1477
IC 2149
UGC 3596
NGC 1931
IC 405
CRL 618
Palomar 2
HBH 9
Open cluster
Open cluster
Dark nebula
Planetary nebula
Lenticular galaxy
Reflection/Emission nebula
Emission/Reflection nebula
Pre-planetary nebula
Globular cluster
Supernova remnant
HD 49009
BRIGHTER OF THE TWO Which is easier to see - NGC 2281
(above) or M37? The author determined M37 to be a smidgen brighter
by eye alone, despite the fact that it lies almost three times farther than
NGC 2281, at around 4,500 light-years. Jim Thommes captured this image
using a 6-inch Maksutov-Newtonian at f/4.8.
cluster has a 9.2-magnitude lucida (HD 39183) almost dead
center, while the stars around it are arranged like rose petals
on a pond. With my 16-inch Dobsonian at 68×, the lucida is
topaz-colored, and I can easily see the water-strider asterism
that Contributing Editor Stephen James O'Meara mentions
in his book Deep-Sky Companions: The Messier Objects.
Mag(v)
5.4
5.6
Size/Sep
25′
15′
-
10.6
12.8
-
-
~16.3
12.6
-
23′ × 16′
15″ × 10″
1.2′
7′
30′ × 20′
17″ × 3″
2.2′
140′ × 120′
RA
06h 48.3m
05h 52.3m
05h 03.6m
05h 56.4m
06h 55.6m
05h 31.4m
05h 16.3m
04h 42.9m
04h 46.1m
05h 01.0m
Dec.
+41° 05′
+32° 33′
+44° 04′
+46° 06′
+39° 46′
+34° 15′
+34° 25′
+36° 07′
+31° 23′
+46° 40′
Angular sizes 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.
sk yand tele scope .o r g * JANUARY 2025 21

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