Tuesday, September 10, 2013

The Coathanger Club

The al-Sufi Cluster resembles a clothes hanger
During these warm summer nights Nick has been sleeping out doors in his tree house and taking this opportunity to get acquainted with the night sky. Surrounded by redwood trees I am limited to observing one slice of the Southern sky: every two hours another sign of the Zodiac appears, beginning (in early September at latitude 35 degrees North) with Sagittarius at 9 PM, Capricorn at 11 PM and Aquarius at 1 AM. But in addition to spotting prominent landmarks such as the signs of the Zodiac I am learning a lot (from both books and observation) about arcane features of the night sky that are known and appreciated by only a few deep sky fanatics.

For instance, in the year 964, the Persian astronomer Abd al Rahman al-Sufi (known as al-Sufi) published a new map of the heavens that improved on the classic Ptolemaic picture. Al-Sufi was the first to record galaxies outside the Milky Way--the Large Magellanic Cloud (visible from Yemen) and the Andromeda Galaxy which is the most distant object (2 million light years) visible to the naked eye.

He also recorded a tiny asterism known today as al-Sufi's cluster or Brocchi's cluster (after an amateur astronomer who studied it 1000 years later than al-Sufi). It is also called the Coat Hanger--well--because it looks like a coat hanger.

Get out your binoculars for a small but memorable non-drug experience under the night sky.

From the wonderful Astronomy Picture of the Day site, here's a picture of the Coathanger.

Which of you will be the first to spot the "Coathanger Asterism"?  initially discovered 1000 years ago by a Muslim astronomer living in Isfahan in what is now called Iran?

The easiest way to spot the al-Sufi Cluster is to locate the Summer Triangle, which is almost directly overhead in the early fall and consists of the three bright stars Vega, Deneb and Altair (all named, like so many other stars in the sky, by words derived from Arabic). The Coathanger lies about 1/3 of the way along a straight line from Altair to Vega, appearing as a bright patch in the Milky Way. Binoculars will be needed to resolve its coathangerish nature.

The al-Sufi Cluster lies in the minor constellation Vulpecula (Latin for Little Fox).

The world is divided into two categories of people, those few who have seen the Coathanger (al-Sufi's Cluster) with their own eyes (pictures don't count) and the majority who will never experience this little star thrill.

Members of the elite Coathanger Club are rumored to greet one another by exchanging the esoteric gesture that identifies a Viewer of the al-Sufi Cluster--a closed fist placed above the back of an out-stretched palm.

Nick has not yet joined the secret society of Coathangers. It's cloudy right now in Boulder Creek. But on the next clear night he intends to leave the rabble behind and to become a member of the society of "Those Who Have Seen the al-Sufi Asterism."

Will you join me in the Coathanger Club? Or will you choose to remain an Outsider?

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