Astronomy

44 ASTRONOMY • DECEMBER 2018

Interested in observing a red dwarf, supernova remnant,

or galaxy cluster? We’ve got you covered. by Alan Goldstein

Explore nearby

DEEP-SKY GEMS

Red dwarf

Barnard’s Star (6 light-years)

The most common stars in the Milky Way are

not visible to the naked eye. Red dwarfs are

inherently dim, and only those located near us

are bright enough to be seen through the typi-

cal hobbyist telescope. The closest is Proxima

Centauri, just 4.2 light-years from Earth. At 11th

magnitude, it is 100 times fainter than the naked

eye can see. It is also deep in the southern sky,

below the horizon for most U.S. observers.

The next closest red dwarf, at 6 light-years

away, is Barnard’s Star, discovered by Edward

Emerson Barnard in 1916. It has the distinction

of being the fastest star (known as “proper

motion”) in the sky relative to the Sun. Since

Barnard’s Star was discovered, it has moved 17.7'.

That’s slightly more than half the Moon’s appar-

ent diameter. That may not sound like much, but

compared to the other stars, it’s haulin’ hydrogen!

Observing tip: Use a star chart to pick this

9.5-magnitude star out of a rich star field.

he deep-sky observer’s neighborhood is

kind of like yours. You know the house,

grocery store, movie theater, beach, and

mountain closest to your home. Deep-sky

observers know the closest stars, nebulae,

clusters, and galaxies in their solar neigh-

borhood. But travelers can’t drive to visit these objects;

instead, the light comes to them. Some are visible to the

naked eye, others require binoculars, and a few necessitate

a telescope — though none requires large optics.

You might think the closest deep-sky objects are dis-

tributed randomly across the sky, but that’s not the case.

They are scattered in right ascension — some are “up” at

any given time of the year. But oddly enough, there is a

strong bias in declination. Of the nearest celestial objects

featured here (see table on page 4 6 ), only two — the

Hyades cluster and Andromeda — are north of the celes-

tial equator. Three on the list — a red dwarf star, a mul-

tiple star, and a supernova remnant — are deep in the

southern sky, beyond the range of U.S. observers. For

those, the selection chooses the nearest suitable targets

for mid-northern latitude observers. The remainder lie

slightly south of the celestial equator.

T

Barnard’s Star: Note the red dwarf ’s change in position between 1950 (right) and 2010 (left).

OBSERVING TARGETS

CHRIS SCHUR

RIGHT:

PALO

MAR OBSERVATORY SKY SURVEY; LEFT: ANTHONY AYIO

MA

MITIS