Astronomy

56 ASTRONOMY • JULY 2018

1990s, Utah amateur astronomer Kim Hyatt added

more pairings to form a complete 40'-wide circle,

now known as the Cygnus Fairy Ring.

Moving about 1½ ̊ west-northwest of magni-

tude 3.7 Tau (τ) Cygni, we come to the remarkable

binary star 61 Cygni. The pair is composed of a

deep-orange 5th-magnitude primary with a simi-

larly colored 6th-magnitude secondary, only 28"

apart. Through a 3-inch refractor at 60x, the stars

look like a nocturnal animal’s eyes reflecting light.

In 1792, Italian astronomer Guiseppe Piazzi chris-

tened it the Flying Star for its unusually large

proper motion, about 5" per year — the seventh

highest known.

Delta (δ) Cygni is one of the bright stars

that will become Earth’s “North Star” around

a.d. 11,250 due to the precession of our planet.

And like our present Polaris, Delta is a binary star.

The blue giant 3rd-magnitude primary is accom-

panied by a white 9th-magnitude secondary only

2.8" away. The star can be split in a 2.4-inch

refractor, but it’s best viewed through 4-inch and

larger telescopes at powers of 150x or more.

Next, locate the beautiful double star 16 Cygni,

some 2¼° southeast of 4th-magnitude Iota (ι)

Cygni. These twin 6th-magnitude yellow stars

resemble our Sun, are separated by 40", and are

beautiful at low magnification with any instru-

ment. The pair’s southeastern member is orbited

every 2.2 years by an exoplanet about 2.5 times the

mass of Jupiter.

Keep your telescope pointed at 16 Cygni,

because we are about to jump eastward to our next

object — one in a very different class.

Blowing off

Planetary nebulae — shells of gas ejected by, and

moving out from, the hot cores of dying red giant

stars — portend the fate of our Sun. One special

example is the Blinking Planetary (NGC 6826),

so named because it appears to blink when you

alternate between direct and averted vision. Look

directly at it, and you’ll see the bright central star;

a glance to the side, which uses your eyes’ more

sensitive rods, brings out the faint nebula. Actually,

just about all planetary nebulae blink, but the phe-

nomenon stands out prominently with this one.

You’ll find this unusual gem about ½°

east–southeast of 16 Cygni. It shines at magnitude

8.5 and is visible as a star in handheld binoculars.

Telescopically, at powers of 75x and higher, it

NGC 7008 is a planetary
nebula with a distorted
appearance and bluish-
green color. Two bright stars
lie near its edge. BOB FERA

One of the most unusual
planetary nebulae in the
sky, NGC 7027 is a relatively
young object shaped like
a dumbbell. ADAM BLOCK/MOUNT
LEMMON SKYCENTER/UNIVERSITY OF ARIZONA