Date: November 16, 2010
Title: Aliens in the Eyepiece
Organization: RapidEye Observatory – http://www.rapideye.us/astro/RapidEye-ClearSky.html
Description: When people ask if I can see aliens with my telescope, I always say, “Yes, I can see an alien with my telescope almost any night of the year!”
Bio: I’ve been captivated by astronomy ever since I was a kid, living in NW Colorado where the Milky Way was bright enough to read by. I can be found most clear nights in my pasture with either my 4.5″ SkyQuest, 10″ Deep Sky Hunter, 18″ Obsession, or my binoculars.
RapidEye Observatory – a private observatory in rural Lee County, NC
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Transcript:
Aliens In The Eyepiece
When people first see my telescopes there are some common small talk and/or light hearted questions they will ask, such as: “How far can you see with it?” or “Can you see the International Space Station?” or my personal favorite “Have you ever seen a UFO or an Alien?”. I have some equally light hearted answers lined up: “I can see all the way” or “Yes, I can easily see the ISS even without a telescope” and again, my favorite, “Yes, I can see an alien with my telescope almost any night of the year!” The third answer might cause other astronomers to take a step back away from me.
But wait, before steping too far away, I’m not claiming to have seen Percival Lowell’s Intelligent Martians through my telescope. Nor have I seen Sir John Herschel’s herds of bison wandering the planes of our moon.
What I am actually referring to is the Open Cluster in Cassiopeia, NGC 457. Many observers also know this cluster as “The Owl” cluster, the “Kachina Doll” cluster, or even “The Dragonfly” cluster. But anyone of my generation that grew up seeing Elliott’s Extra Terrestrial friend running across the silver screen waving his arms over his head will always refer to this Open Cluster as “The E.T.” cluster.
This cluster was originally cataloged by William Herschel in 1787 with his 18.7″ reflector. He recorded it as a Large and Bright Cluster, pretty rich, with stars of 7th, 8th and 10th magnitude. The true members of the cluster itself are classified as 6.4 Magnitude and 13 arc minutes across, and using the more contemporary Trumpler classification system, it is classified as a II 3 r, which translated to English means it is clearly detached with a light stellar core with a wide magnitude of stars, and more than 100 associated members.
NGC 457 resides in the glow of the Open Cluster Rich area of the Milky Way that runs through Cassiopeia and is between 7,500 and 10,000 light years away from us. Here in Central North Carolina, NGC 457 is technically considered a circumpolar object, meaning, it never sets below the northern horizon. In reality, it does get below 5 degrees from the northern horizon and unless I have an exceptionally clear night it does disappear from view when it is down that low. From locations north of 40 degrees with a good clear northern horizon, our alien friend should be visible all night long every night of the year. So from locations like Boston, Seattle, or London you can watch E.T. tumble around and do somersaults as he rotates around the celestial north pole.
While Charles Messier didn’t catalogue this cluster in his famous list of objects, Sir Patrick Moore did include it in his list of Caldwell Objects under entry number 13. Even without the notable shape visible in the cluster, it is a remarkably pretty cluster that shows a good range of brightness in the stars as well as a good sampling of colors. While not as flashy as its nearby neighbors, the double cluster in Perseus, it is much easier to find and appriciate than most of the other open clusters in Cassiopea such as Messier 52 and Messier 103.
OK, so how to find it:
Here in the Northern Hemisphere, this time of year Cassiopeia looks like a wide letter “M” around 9 – 10 PM local time. Using either a finder scope or a pair of medium power binoculars, extend a line along the right leg of the “M” made by Delta and Epsilon Cas and continue approximately 2 degrees above Delta Cas, you should easily see the two “eyes” of E.T. set above the rest of the cluster. Even without optical aid, at magnitude 5, one of E.T.’s eyes is readily visible from reasonably dark skies.
What to expect at the eyepiece:
While Herschel used his 18.7″ telescope to discover the cluster, at magnitude 6.4, it is a fairly bright object and is easily seen using telescopes as small as 60mm or even 10×50 binoculars. But to really appriciate this object, I find that a 4″ telescope and magnifications higher than 25X really work best. Additionally, in my opinion, a field of view of around 3/4 of a degree gives the most pleasing view, framing the core cluster making up E.T.’s body and Eyes as well as keeping the extended members that make up E.T.’s arms or the Owl’s wings, depending on your view. Increasing the aperture to a 6″ or 8″ will reveal many more stars, perhaps 60 to 70, making it an even more captivating view. Significantly larger apertures will reveal even more stars in the cluster, but actually make it more difficult to make out the E.T. or Owl shape in the cluster.
I find that my 10″ telescope is about as large of aperture as I want to use from reasonably dark skies.
And since this is a fairly loose and bright open cluster you don’t need to phone home to see it. It is readily visible even in moderately light polluted skies, making it an excellent object for public outreach events that are held in community parks, schools, or boardwalks. Also, unlike many other deep sky objects, its is easy to see and study at the eyepiece, even with eyes that aren’t dark adapted. There is a good variety of colors in the cluster, red, blue, white and some nice yellow stars. And everyone I’ve shown it to at a star party easily sees the alien or the owl. When they leave it night, they might not remember what galaxy they saw or the Messier number of the Globular Cluster they enjoyed, but the public always seems to remember seeing the little Alien in the Eyepiece. Oh, and leave the Reese’s Pieces at home – its is very hard to clean peanut butter smudges off of an eyepiece!
End of podcast:
365 Days of Astronomy
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