Astronomy

t

SAGITTARIUS

CAPRICORNUS

52

/

31

Path of Mars

May 1

15 June 1^15

July 1

15

Aug. 1

15

m

t

p

62

59

60

2°

E

N

WWW.ASTRONOMY.COM 61

latitude of 45°. In the southern hemisphere, the seasonal
ice cap never passes above a latitude of about –55°.
Don’t confuse the Hellas Basin with the polar cap.
Hellas is a round, bright feature — an impact basin with
lots of bright dust and sometimes fog or clouds. When
seen near the limb (the planet’s edge), it can look like a
polar cap.
With respect to clouds, all of them on Mars are tem-
porary. Discrete clouds associate with a specific area,
and Mars’ rotation carries them along.
Orographic clouds are a type of discrete cloud. Wind
passing over high mountains and volcanoes creates
these water-vapor clouds. Observe orographic clouds
through a blue or violet filter to see the most contrast.
Look away from Mars’ meridian and observe morn-
ing and evening clouds. These bright, isolated patches
of surface fog appear at sunrise (the western edge of
Mars) and sunset. Evening clouds generally appear
larger and are more numerous, and as the martian night
approaches, they grow larger. These clouds respond best
to blue or violet filters.
Color filters show a lot when you observe Mars, but
they do take some getting used to. Be patient, and you’ll
be amazed at how much more detail you’ll see.

No need to rush
Although Mars will appear biggest July 31, it will look
almost as bright several weeks before and after that date.
So, if you’re clouded out, or if the 31st just doesn’t work
for observing, cheer up. Unlike totality during a solar
eclipse, a martian opposition isn’t a short-lived event.
Just keep in mind that the best time to observe Mars

is any night it’s in the sky. Once every 26 months, Mars

appears bright in our sky, but some of these appearances

— like this one — are better than others. Take advantage

of the planet’s size and brightness, and don’t worry so

much that it’s so low in the sky. Head out to a science

center or observatory, contact your local astronomy club,

or simply point your scope at the Red Planet. Then focus

and take a good, long look.

Michael E. Bakich is a senior editor of Astronomy. He also is

a longtime observer of the Red Planet, having traced its path

along the zodiac starting in the 1960s.

Mars’ motion

across the stars

takes it through

the constellations

Sagittarius and

Capricornus from

May 1 through

August 31.

ASTRONOMY: RICHARD

TALCOT T AND ROEN KELLY

This image,

taken October

23, 2014, shows

Mars (bright

object at bottom

center) passing

by the Lagoon

(M8) and Trifid

(M20) nebulae

in Sagittarius.

DEREK DEMETER