Auriga Galactic Star Clusters.
Among the many thousands of open star clusters that abound the starfields of our Milky Way galaxy are the three
well known Messier clusters in the constellation of Auriga.
The three clusters named M36 (NGC 1960), M37 (NGC 2099), and M38 (NGC 1912) can be found high
in the sky throughout Winter months. All three can be viewed easily on clear Moon less nights with a pair of binoculars
and appear as hazy patches of light with some star mottling. However when seen at low power magnifications by astronomers
using 6 to 8 inch reflectors they look magnificent.
Links to pictures:...............Messier 36 pic................Messier 37 pic................Messier 38 pic
M38 has the highest Declination and can be found in the sky at RA 5.28.7 DEC +35.50 (2000 epoch). The cluster
contains over 100 stars and its appearance has an irregular form with a diameter of about 20 minutes of arc.
The true cluster diameter however is around 25 light years and lies at some 4200 light years distance from us.
Many G type giants are within the cluster and the brightest member at magnitude 7.9 is a GO type yellow giant.
Close to M38 is the smaller open cluster NGC 1907.
M36 is a little lower and can be found at RA 5.36.1 DEC +34.08 (2000 epoch). It is found about 2.3° distant
from the cluster M38 and lies about 5° southwest of Theta Auriga .
This smaller tighter bound cluster containing some 60 stars is however a little brighter than M38. The cluster
is best seen using a power of about X 50 using a 6 or 8 inch reflector. The cluster is a very young one and contains
no older red giant stars. Its brighter members are all B type stars ranging between 9th and 11th magnitude. The
true cluster diameter is about 14 light years and it lies at a distance of over 4000 light years.
M37 finally can be found at RA 5.52.4 DEC + 32.33 (2000 epoch) is one of the finest open star clusters in the heavens.
Stars in this cluster can be resolved in any telescope with a aperture larger than 2 inches and is a truly magnificent
sight in a 6 inch reflector. This in my opinion is the finest cluster of the three. It contains some 150 stars
brighter than 12th magnitude of which many suggest a much older well evolved star group than those in M36. The
stars include several red giant stars and one, the brightest, has a visual magnitude of 9.5. The clusters true
diameter is about the same as M38 around 25 light years. It lies at a distance of 4600 light years. In all Auriga
has three jewels of the heavens in these clusters and they will forever be a pleasing sight to see by all I feel.
By: John R Fletcher Mount Tuffley Observatory. UK.