Trumpler 37 & IC 1396 -- Open Cluster & Nebula in Cepheus
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The Royal King’s Diamonds
The King’s diamonds span nearly the size of two full moons in the night sky.  King
Cepheus diamonds are piled thick and high next to a giant ruby;
Herschel’s Garnet
Star.  It is a remarkable section of sky through binoculars, wide-field telescopes and
even standard amateur telescopes.  There is plenty to keep an observer mesmerized
for hours.  Check out your colored star charts and you will see how impressive this
corner of the universe is.

The 480+ stars that make up the Open Cluster, Trumpler 37, is the brightest and
largest (apparent) deep sky object in Cepheus.  At magnitude 3.5 the huge cluster is
visible without aid under a dark sky.  The cluster is full of double stars while at its heart
is a magnificent 6-star system (Struve 2816) in which three of the stars (all different
colors) are visible in the smallest of telescopes. Faintly embedded in and around the
cluster is an emission nebula (IC 1396) reminiscent of (but fainter) than the Rosette Nebula. A
nebula filter on binoculars or a rich-field telescope is needed to tease the
nebula out.

My main eyepiece for the drawing was a 41mm Panoptic on the 155mm refractor with
a field reducer.  This gave me 3.22-degree field-of-view at 20 power.  I also used an
UHC (specialized nebula filter) when searching out the boundaries of the nebula.  Even
from my backyard I was able to draw the brighter sections of the nebula, although a
darker site would have been better.  For the double stars and a slightly closer look at
the cluster and nebula I used a 21mm eyepiece at 52x power.

The King’s diamonds are nearly straight overhead at this time of year after the sun has
set. Do yourself a favor and put your binoculars or telescope on it (use the eyepiece that
gives you the widest field-of-view).  Equally important is spending some time observing this
area of Cepheus.  Even if you don’t observe anything else that night, you will fondly
remember the King’s diamonds.