SKY_July2014.pdf

OBSERVING

Deep-Sky Wonders

6654

6654A

Kemble 2

Pothier 3

χ

δ

ε

φ

η

π

σ

τ

υ

ψ

ζ

15

34

50

β

γ

η

URSA MINOR

R

6140

6340

6412

6503

6643

6543

DRACO

20 h 19 h^18 h 17 h 16 h 15 h

+70°

+65°

Star magnitudes

5

4

3

6

7

8

9

56 July 2014 sky & telescope

Betwixt the Bears

Draco’s eastern loop is highest on warm summer nights.

Betwixt the Bears, like foaming river’s tide,

The horrid Dragon twists his scaly hide.

To distant Helice his tail extends,

In glittering folds round Cynosyra bends.

Swoln is his neck — eyes charg’d with sparkling fi re

His crested head illume. As if in ire

To Helice he turns his foaming jaw,

And darts his tongue barb’d with a blazing star.

— Aratus, Phaenomena, translated by John Lamb 1847

This charming verse teaches us how to fi nd the sky’s

enormous dragon, Draco. His tail lies betwixt the bears

Ursa Major (Helice) and Ursa Minor (Cynosyra), whose

brightest stars form the familiar patterns of the Big

Dipper and Little Dipper. Look between the bowls of the

dippers to spot the tail, and then follow Draco’s serpen-

tine chain of stars as he bends around the Little Dipper

and then folds back on himself as if trying to sneak up on

Ursa Major from behind.

Draco’s hairpin turn enfolds one of my favorite aster-

isms, Kemble 2. The late Canadian amateur and Fran-

ciscan friar Lucian Kemble found this delightful group in

1994. In an unpublished paper the following year, Father
      Kemble wrote, “While browsing through Uranometria
      one day I came across a most unusual bright asterism in
      Draco.” His interest piqued, Kemble took up binoculars
      for an eyes-on view of this copycat asterism.
      Kemble’s Norwegian friend Arild Moland says that
      “it bears an almost scary resemblance to Cassiopeia.”
      Others noticed the likeness as well, thus the asterism is