Sue French
Stars and Galaxies in the Celestial Dragon
Object Type Mag(v) Size/Sep RA Dec.
Kemble 2 Asterism 5.6 30 ′ 18 h 35.0m +72° 23 ′
NGC 6654 Galaxy 12.0 2.6′ × 2.1′ 18 h 24.1m +73° 11 ′
NGC 6654A Galaxy 12.9 2.6′ × 0.8′ 18 h 39.4m +73° 35 ′
NGC 6643 Galaxy 11.1 3.8 × 1.9′ 18 h 19.8m +74° 34 ′
Psi (ψ) Dra Double star 4.6, 5.6 30 ′ 17 h 41.9m +72° 09 ′
Pothier 3 Asterism — 25 ′ 17 h 27.8m +72° 14 ′
R Dra Variable star 6.7 – 13.2 — 16 h 32.7m +66° 45 ′
NGC 6140 Galaxy 11.3 6.3′ × 4.6′ 16 h 21.0m +65° 23 ′
Angular sizes and separations are from recent catalogs. Visually, an object’s size is often smaller than
the cataloged value and varies according to the aperture and magnifi cation of the viewing instrument.
Right ascension and declination are for equinox 2000.0.SkyandTelescope.com July 2014 57Sue French welcomes your comments at [email protected].
nicknamed Mini-Cassiopeia. In his book The Deep Sky:
An Introduction, Philip S. Harrington calls this striking
bunch the Little Queen.
Kemble 2 sits 1.1° east-southeast of Chi (χ) Draconis.
Its fi ve brightest stars form a pattern very similar to the
familiar W shape of Cassiopeia, the Queen. There’s even
a sixth star corresponding to Eta (η) Cassiopeiae, albeit
slightly out of place. Kemble 2 is quite colorful through
my 130-mm refractor at 37×. Starting at the northernmost
star and working my way along the W shape, the six stars
appear orange, gold, orange, gold, gold, and yellow-white.
The barred galaxy NGC 6654 dwells 30′ north-north-
east of Chi Draconis. My 130-mm scope at 37× shows a
small hazy patch enshrouding an elongated bar and is
accompanied by an 11th-magnitude star 2.4′ to its west. At
63 × the haze is a north-south oval, while the bar tips east
of north and hosts a tiny, bright center. With a magnifi ca-
tion of 117×, the galaxy’s oval profi le looks about 1¾′ tall.
My 10-inch refl ector at 115× discloses a starlike nucleus
nested within the little, round core at the bar’s center.
NGC 6654A lies 1.2° east-northeast of NGC 6654.
Galaxy expert Harold Corwin told me that the object’s
designation comes from a 1935 paper by Philip C. Keenan
in the Astrophysical Journal. Keenan discussed Yerkes
Observatory’s method for determining galaxy magnitudes
from photographic plates. Any previously uncataloged
galaxy discovered on a plate was assigned the name of
the nearest NGC object on the plate, with a capital letter
appended. Although Keenan intended these designations
to be temporary, the name NGC 6654A has become popu-
lar with amateur and professional astronomers.
NGC 6654A is barely visible with averted vision
through my 130-mm refractor at 63×. It’s just a ghostly
little smudge hovering over the western point of a 3.7′-
long triangle of three dim stars. I still need averted vision
at 91× but suspect the galaxy is slightly elongated.
NGC 6654A is still very faint in my 10-inch scope at
166 ×. At 213× the galaxy looks a bit oval and 1¼′ long, but
the center is a skosh brighter and roundish. I thought I
saw an extremely faint star at the galaxy’s visible easternend, which is actually well within NGC 6654A on images.
I used the Aladin Sky Atlas (http://aladin.u-strasbg.fr/
aladin.gml) to check it out.
Although visible-light images that I accessed via
Aladin confi rmed an object at this spot, it was diffi cult
to tell if it was a foreground star or an H II region within
NGC 6654A. To identify the object, I overlaid catalogs on
an image and was astonished to see that it’s classifi ed
as a galaxy in some of them. I didn’t believe it. Astrono-
mer Brian Skiff helped me out by examining the object
in mid-ultraviolet, far-red, near-infrared, and thermal
infrared images. He concludes that this spot is probably
an immense cluster of O-type stars inside a giant H II
region, something like the Tarantula Nebula in the Large
Magellanic Cloud. Harold Corwin concurs. If anyone with
a very large telescope can detect a contrast enhancement
of this star-forming complex when blinking with a nebula
fi lter, I’d love to hear about it.
The fl eecy-armed spiral galaxy NGC 6643 hovers 1.8°
north of Chi Draconis. My 130-mm scope at 63× displaysNGC 6654 NGC 6654A NGC 6643POSS-II / CALTECH / PALOMAR OBSERVATORY (3)