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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 a particular constellation as well as describing the numerous deep sky objects residing within its boundaries. 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 Cepheus the King.

Deep Sky Report
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!
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.
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.
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!