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Constellation
Report |
| Our Constellation report is an easy way for people to
become familiar with the nighttime sky. We’ll discuss myths associated
with the various constellations as well as describing the numerous deep
sky objects residing in the area. No equipment is required to view the
constellations, though a star chart can be quite helpful. This ease of
observing makes constellations a natural place to begin your journey to
the stars.
 This weekend we move on to the constellation
Monoceros the
Unicorn. Unicorn's are mythical creatures with the legs of a deer, the tail of a lion,
and the head of a horse. There is one horn growing straight out of the center of the head. The stars of the constellation are faint and illusive, just
like the Unicorn. In many cultures, the tiny crescent moon is said to represent the horn of the Unicorn. Given that
Orion is a mythical hunter, it's pretty funny to have a highly prized Unicorn standing right behind a mighty
hunter.
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Deep
Sky Report
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Monoceros is home to a few beautiful and interesting multiple star systems.
First up is Beta Monocerotis mag4.6. This is actually a beautiful triple star system. The first two stars (A&B) are about mag5 and are separated by about 7.5" The
third star is about 2.8" from the B star forming a beautiful triangle.
Another interesting star is known as Plaskett's Star, after astronomer J.S. Plaskett who first observed it in 1922. These are probably the largest pair of stars known to
exist in our galaxy... Estimates put the two stars at about 60 and 40 times the mass of our Sun. The pair are about 2700 light years distant making them about 3000
times brighter than our star..
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 First up is the only
Messier object
on the list; a beautiful Open Star Cluster M50(mag5.9). M50 is a beautiful
object which can be spotted in binoculars. It's home in the midst of a
dense portion of the Milky Way only
enhances it's beauty. M50 can be found about 7° north of mag4 Gamma Canis Majoris.
Estimates on the number of stars in this cluster vary greatly as it is actually pretty difficult to determine the actual end of the
cluster and the start of the Milky Way background. M50 is probably about 3,000 light years distant. Its angular
diameter of
about 15x20' therefore corresponds to a physical diameter of about 18 light years. There are
about 200 member stars in the
cluster and it is estimated that the age of the cluster is around 78 million years.
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 Next up is the beautiful
Rosetta Nebula complex NGC2237-9(mag5.5)
This beautiful object absolutely requires a nebula filter. It doesn't matter
which one you've got... though I prefer an OIII filter. Without a filter this
object is virtually invisible. Even with the big scope under dark skies I could just barely detect the nebula. Pop in the filter and
WAM! The nebula jumps right out at you. This is a large object - spanning about70'x80'. I
could not fit the whole thing inside my lowest power, widest angle eyepiece. So... depending on your setup, you may have to move around to
view it all. But... it's definitely worth the effort. This is one beautiful, highly
detailed nebula. We spent quite a bit of time looking at it. We'd swap nebula filters...and eyepieces... and fight for turns on the ladder. You'll definitely enjoy this object.
This awesome shot was taken by none other than Robert
Gendler.
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 Next up is
Open Star Cluster NGC2244(mag4.8). Also known as the
Rosetta Cluster, this object is classified as an open star cluster, but.. .from
the picture you're immediately overwhelmed by the nebulosity. This nebulosity is actually part of the huge Rosetta Nebula. This small cluster is
actually a "freebie". If you find the Rosetta Nebula, you're bound to find this
cluster. If you haven't found the nebula (you are using a nebula filter, aren't
you:) you might use this tiny cluster as a reference... it sits right in the
middle of the nebula. In an 8" telescope, you'll see about 3 dozen stars with many more appearing as you increase the aperture. To find this
cluster, travel about 9° ESE of Betelgeuse.
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 Continuing along, we come to
Open Star Cluster NGC2506(mag7.6).
Located about 15° south of Procyon or about the same distance east of Sirius, this is a beautiful object in binoculars or a small telescope. In a
large telescope, it is absolutely stunning. Checkout this beautiful "Open"
star cluster. Give it a quick look and you might think it was a loose globular
cluster. In fact, it's pretty much a "typical" open star cluster. Not too dense,
and not too loose. What makes it appear so dense is the fact that it's superimposed onto a fairly dense portion of the Milky Way. So, the
combined density of cluster stars and background stars makes this object look so cool.
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 Next
up is yet another fine Open Star Cluster, NGC2343(mag7.2) This
object, which has about as many members as NGC2362, will actually show
more stars in smaller instruments. A 6-8" telescope will reveal
almost twice as many stars as NGC2360. It's not until you move up to
larger telescopes that you begin to pull some of the fainter members of
NGC2362 into
view.
In the eyepiece, NGC2362 is simply beautiful. It's
delicate internal structures will entice you. Another thing to note is the
fact that there is no really distinct ending to this cluster. It simply
blends into the surrounding Milky Way.
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 This movie (an animated GIF)
shows the expanding light echo of nova V838 Monocerotis, discovered by an amateur in January 2002. Made by
Al Kelly from images taken by Arne Henden of the
US Naval
Observatory in Flagstaff, AZ. Arne made UVBRI image sets in January, May, September,
and November. The GIF comprises a sequence of L/RGB color composites made from these image sets.,
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 Continuing,
we come to a beautiful Open Star Cluster with Nebulosity,
NGC2264(mag4). Actually, this picture is deceiving... yes I know.. many
deep sky shots are deceiving. You won't see this much nebulosity. You'll
mostly see the star cluster... with a bit of nebulosity surrounding it.
You'll benefit from a nebula filter...dark skies... and aperture... yes I
know... you benefit from those three things in virtually every observing
situation.
Anyway.. Checkout this awesome shot of The
Cone Nebula by Robert
Gendler.
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 Let's wrap things up with this weeks
Utah Skies Challenge Object, a fine nebula known as Hubble's Variable Nebula - NGC2261(mag10). We
observed this beauty through the
25" ObDob under the dark skies of
southern Utah. It was quite an impressive site.
Located about 5° northeast
of the Rosetta Nebula, this is not a terribly challenging
object. Under
reasonably dark skies, and with just a bit of patience you should be all
over this one.
What makes this object so interesting is that it has been
seen to vary in size,
brightness, and structure over time. Since Hubble's
Variable Nebula is a reflection
nebula, we see it because of light reflecting
off of it. Astronomers have speculated that
shadows cast by moving
clouds of gas and dust cast shadows on the nebula. It is
believed that
these clouds are moved around by solar wind emanating from the star R
Monoceros. It is thought that these moving clouds are what cause the
nebula to vary so
dramatically.
Visually, this object looks very much like a
comet... even displaying a bit of a tail. This
object has a reasonably high
surface brightness, allowing telescopes from about 6" and
up to display
some nice views. As it's fairly bright, you should be able to benefit from a
bit of magnification as well.
Good Luck!
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