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
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
N
p
/
m
CAPRIC ORNUS
June 1
15
May 1
Path of Mars
July 1
E
15
15
31
t
t
Aug. 1
52
SAGIT TARIUS
60
15
59
62
2°
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.
Mars’ motion
across the stars
takes it through
the constellations
Sagittarius and
Capricornus from
May 1 through
August 31.
ASTRONOMY: RICHARD
TALCOTT AND ROEN KELLY
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.
W W W.ASTR ONOMY.COM
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