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Deep
Sky Report
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The focus of our efforts this
week will be the deep sky objects of Cepheus. Cepheus is located
to the north, northeast of Cygnus which we covered several weeks
ago. This circumpolar constellation represents the Ethiopian king, Cepheus (SEE-fee-us). He sits atop the Milky Way on a throne near his queen Cassiopeia who we'll visit in the not too distant future.
To find Cepheus, look high and towards the north after sunset. Cepheus is home to, among other things, the Garnet Star.
The Garnet Star is one of the reddest stars known.
The Garnet Star is a huge red giant, much like Betelgeuse in Orion, its size is
uncertain but, recent estimates place it at about 15 astronomical units across. If it replaced the Sun, it would extend midway between the orbits of Jupiter and Saturn.
In other words, we would be inside it. Its distance and apparent brightness suggest an extraordinary luminosity
roughly a quarter million or more times that of the Sun! |
Let's
start
things off with a beautiful wide-field image of the region by Astrophotographer
Jerry Lodriguss. This shot
was a 5 minute exposure made with a 85mm f/1.4 Nikkor lens operating
at f/2.8. Awesome!
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Let's
continue by observing a beautiful face-on Spiral Galaxy NGC6946 (mag9.0).
This galaxy loses a bit of brightness by lying close to the plane of
the Milky Way Galaxy. Oh, well. You can find this galaxy with a 10" telescope under decent skies... perhaps with a
8" under
pristine skies. With this much aperture, you should expect to see
little more than the galaxy core. To see the beautiful spiral arms
requires significantly more aperture and dark skies. Certainly my
mag5.5 home skies were not up to the task.
This
awesome shot was taken by Robert
Gendler.
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Also
in Cepheus and right next to our previous object is Open Star
Cluster NGC6939(mag8) This sparse cluster looks especially nice
after spending time trying to coax details out of NGC6946. |
Let's
take another quick step back for this beautiful wide angle shot from
Jerry Lodriguss. This shot
contains both NGC6946 and NGC6939. Cool, huh? Jerry took this image
by making a 70 minute exposure through an Astro-Physics 130 EDT f/8 refractor. |
Also
in Cepheus is a Bright Nebula IC1396(mag3.5). Don't let the mag 3.5
fool you. This object is so big at 2.5° that you'll have trouble
fitting it in most scopes. Unless you're along the periphery, you
might not even realize you're looking at a nebula. This is another
candidate for a nebula filter |
Also
in Cepheus is a Bright Nebula NGC7822. This is extremely large at
roughly 2°. It is also pretty faint. To find it, you'll probably
need dark skies and a nebula filter. Only in a Robert
Gendler image should you expect it to look this good :) |
Next
up is Open Star Cluster NGC188(mag8.25). Located only 4° from
Polaris, this cluster is visible year round. It's also pretty
large... spanning roughly 15'. Home to over 150 stars, it appears as
a soft glow in a 6" telescope. To resolve its mag13+ stars will
require a bit more aperture and dark skies. NGC188 is the oldest
known galactic cluster. |
Continuing
along, we come to Bright Nebula,
NGC7023(mag7). Older star catalogs not surprisingly missed the
cluster altogether and labeled it a Diffuse Nebula. In fact, the
nebulous structure is the most interesting anyway.
This gorgeous shot of The Iris Nebula
was taken by Chris Deforeit. If you'd like to see more of Chris'
awesome work... and there is quite a bit of it... checkout his Astrim
website.
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Continuing
along, we come to Emission Nebula Sh2-155 also known as the Cave Nebula. This beautiful image
by Astrophotographer Michael
Stecker is about as good as it gets. In fact, visually, The Cave
Nebula is quite challenging. |
Continuing
along, we come to vdB-142. This awesome shot was taken by Al
Kelly, a former Utah
Skies Astrophotographer of the Month. |
We'll wrap up our journey
through Cepheus with a visit to this weeks Utah Skies Challenge
Object, Planetary Nebula NGC40(mag11). This interesting little
object displays a considerable amount of detail. It appears
star-like at low powers, but begins to show its nebulous detail at
higher powers in telescopes of about 8" or larger. Nebula
filters can help you on this one.
Good Luck! |