skyandtelescope.com• FEBRUARY 2020 47Between February 14th and 17th,
Mercury fades from magnitude +0.2
to 1.6. It’s lost soon after as it dims by
about one magnitude or more every two
days on its way to inferior conjunction
with the Sun on the American evening
of February 25th. On the American
evening of the 15th, Neptune is a mini-
mum of 5.8° east of Mercury before
the latter starts moving away from
it. Neptune becomes lost in the Sun’s
afterglow on its way to conjunction
with the Sun on March 8th. Uranus
is much higher for observation at dusk
(and right after dusk) than Neptune is
this month. Detailed fi nder charts for
Uranus and Neptune are in the Septem-
ber 2019 issue and can also be accessed
at https://is.gd/urnep.
PRE-DAWN AND DAWN
Mars rises about three hours before the
Sun in February, its brightness improving
from magnitude 1.4 to 1.1. Watch the
orange-gold planet as it marches above
the Teapot of Sagittarius in the second
half of February. The greatest morning is
that of the 18th when viewers in most of
North America get a rare opportunity to
see an occultation of Mars by the Moon.
Will the event be before or after sunrise
from your location? See page 50 for more
information on this occultation. The
angular diameter of Mars increases from
4.8′′ to 5.5′′ this month, still very small
for detecting any telescopic detail.
Jupiter starts the month rising more
than 1½ hours before the Sun and ends
the month coming up about 2½ hours
before the Sun. Saturn’s lead on the
Sun increases from less than one hour
to about two hours during February.
Jupiter shines east of the Teapot of
Sagittarius and is slowly gaining ground
on Saturn, which in turn is nearing the
borderline of Sagittarius and Capricor-
nus. Follow as the two gas giants trek
eastward relative to the background
stars. Mars is gaining ground much
more swiftly on Jupiter and Saturn, and
next month will pass close to the pair.
During February, Jupiter brightens
from –1.9 to –2.0, while Saturn dims
from +0.6 to +0.7. The globe of Jupitergrows ever so slightly, from 32′′ to 34′′,
the globe of Saturn even less so, from a
bit wider than 15′′ to 15½′′. These usu-
ally well-defi ned worlds are unlikely to
appear sharp in the telescope because
they’re still quite low in the southeast
as dawn brightens.
By the way, Saturn is at its descend-
ing node (crossing the ecliptic, the plane
of Earth’s orbit) on the 13th, just two
days before Venus is at ascending node
and only 13 days before Jupiter itself
reaches descending node. The last two
classic planets also pass through the
ecliptic this month: Mars is at descend-
ing node on February 1st and Mercury
is at ascending node on February 7th.MOON PASSAGES
The Moon, waxing gibbous, is in the
Hyades at dusk on February 3rd. The
next evening, it’s some degrees right or
upper right of Zeta (ζ) Tau. The waning
crescent Moon occults Mars above the
Teapot of Sagittarius for many observers
before or at sunrise on February 18th. At
dawn on the 19th, the thinning lunar
crescent has moved to a few degrees right
of Jupiter, while on the 20th viewers will
see the crescent some 2 ° to 3° lower
right of Saturn. The waxing lunar cres-
cent is well to the left, some 5° or more,
of Venus at dusk on February 27th.¢FRED SCHAAF lives on the edge of
the New Jersey Pinelands Reserve, with
no lights for about 10 miles to his east.Jupiter
SaturnUranusNeptuneMercuryVenus
EarthMarsMarch
equinoxJune
solsticeDecember
solsticeSept.
equinox
SunORBITS OF THE PLANETS
The curved arrows show each planet’s movement during February. The outer planets don’t
change position enough in a month to notice at this scale.skyandtelescope.com• FEBRUARY 2020 47Dusk, Feb 26 – 28
45 minutes after sunsetARIESVenusMoon
Feb 26Moon
Feb 27Moon
Feb 28Looking West,
halfway up_ CetDawn, Feb 29
45 minutes before sunriseSAGITTARIUSMarsJupiterSaturnLooking Southeast