Thursday, February 5, 2009

Kemble's Cascade

In the otherwise unremarkable minor constellation of Camelopardalis the Giraffe (kah-MELL-oh-PARR-duh-liss), there is a sort of “scenic overlook” complete with a waterfall. This waterfall is an asterism (star pattern) known as Kemble’s Cascade. It is naked-eye visible only to those with keen eyesight and a dark observing site. Even so, the naked-eye view is a mere smudge compared to the stunning view through binoculars.

Grab your binoculars, and let’s go stretch our necks.

Camelopardalis in Johannes Hevelius’s 1690 star atlas
Courtesy of
Linda Hall Library of Science, Engineering and Technology

1) About an hour after sunset, face north. If you don’t know the cardinal directions at your location and you don’t have a compass, make note of where the sun sets on the horizon. That spot is approximately west. Stand with your left shoulder to the west, and you’ll be facing approximately north.

Star maps created with Your Sky

2) To find the grazing grounds of the shy giraffe, first find the Lazy W asterism in Cassiopeia. Looking north, it should be easy to spot it, just west of the meridian. The Lazy W will be oriented upside down, so it will look more like a big “M.” Draw an imaginary line between the two end stars of the “W” or “M,” and extend it toward the southeast the same distance again. This will bring you very close to Kemble’s Cascade, in the heart of the Giraffe.

3) Another way to home in on the celestial waterfall is to locate the “backbone” of the constellation Perseus, the chain of stars known as the Segment. If you draw an imaginary line between the middle star of the Cassiopeia “M” and the star to its right, or southeast, the next bright group of stars you come to is the Segment. Locate the brightest star in the curved string of six naked-eye stars; this is Mirfak (MURR-fahk), the brightest star in Perseus.

On your way to the Segment from the Lazy W, you crossed a little fuzzy patch in the sky. This is the famous Double Cluster, a pair of star clusters whose combined light is visible to the naked eye. Spot it? If not, you’ll probably need a darker location. If you can see it, draw an imaginary equilateral triangle between Mirfak, the Double Cluster, and a point to the southeast. Now you’re within penny-tossing distance of the waterfall.

By the by, when you’re finished goggling at Kemble’s Cascade, you’ll want to return to the Double Cluster. It’s another superb binocular object.

4) Now that you know where to look, using either method, fix your eyes on the spot where you think the Cascade lies. Don’t take your eyes off that point as you slowly bring the binoculars up to your eyes. You’re going to want to, but don’t do it. If you look AT the binoculars, you will lose your focus on the target in the sky. Keep your eyes glued to your sky target until the bino eyepieces touch your face. Your target should be in the field of view or very close by. This takes a little practice, because the impulse is to glue your eyes to the binoculars first and then sweep around until you (maybe) find the object. You’ll be amazed at how efficient your targeting becomes when you master this little trick.

If you don’t see a long, lazy chain of stars (about 20-plus) in your field of view, make small and ever-widening circles with the binoculars until you spot it.

Here’s a nice image of Kemble’s Cascade that appeared on the Astronomy Picture of the Day website.

5) The sparkling cascade of starlight seems to go on forever, doesn't it? Sweep back and forth along it and look for subtle color differences. You should see some yellowish stars scattered among the white ones.

The stars of Kemble’s Cascade are unrelated. It’s just a happy accident that a nice collection of stars— distant from each other— arranged themselves in space for our stargazing pleasure.

The lovely asterism was discovered by— and named after— the late Father Lucian Kemble, a Franciscan friar and avid amateur astronomer from Alberta, Canada. He discovered it using modest binoculars: 7x35s. So, we have no excuses, eh?

Astronomy Essential: Our solar system has eight planets.

In orbit order from the Sun, the eight planets of our solar system are: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune.

Pluto was once considered the ninth planet in our solar system. However, in 2006, the International Astronomical Union (IAU), the recognized world authority for assigning designations to celestial bodies, demoted Pluto to dwarf planet status. This set off a firestorm of controversy and debate that continues today.

The definition of a dwarf planet— as set forth by the IAU— differs from that of a planet in that a dwarf planet has not cleared the neighborhood around its orbit of debris and small solar system bodies such as asteroids. For Pluto, its environment was its undoing. Its orbit skirts the edge of the Kuiper Belt (KY-purr), a region beyond Neptune’s orbit that is filled with tens of thousands of small orbiting bodies.