This is the Skywatch Line for Monday and Tuesday, May 11th and 12th, written by Joe Slomka.
The Sun sets at 8:07 PM; night falls at 10:05. Dawn begins at 3:38 AM ends with the Sun rising at 5:36.
The Moon is not visible Monday evening. Tuesday’s 19-day-old Moon rises in Capricornus at 12:55 AM, appearing 71% illuminated, 22° high andsets at 10:08 AM. In Sagittarius, Wednesday’s Moon rises at 1:38 AM, is 62% lit, 23° high and sets during daytime.
Venus is the brightest and easiest planet to observe. In Taurus, it is a bright minus 1st magnitude, 14% lit and 21° high. Mercury, also in Taurus, is visible but very low and difficult to see unless there is an unobstructed western view.
The pre-dawn sky is very active. Tuesday, Jupiter is the first to rise, in Sagittarius, at 12:53 AM. Jupiter appears with the Moon 2° belowand Saturn 5° away. Glaring with minus 2nd magnitude, diameter 42 arc-secondsand 21° high, Jupiter rises early enough for observers to witness two events. Tuesday, the moon Callisto disappears behind the planet at 12:24 AM and
reappears at 4:29 AM. Wednesday, the moon Io’s shadow begins to creep across Jupiter at 4:53 AM.
Saturn, in Capricornus, is the second to rise at 1:12 AM,
shining with zero magnitude, 17 arc-seconds wide and 20° high. Monday, the
Ringed Planet appears stationary in the night sky; Wednesday begins a
retrograde (westward) movement until September. Mars is the last to rise, in
Aquarius, at 2:33 AM, appearing as bright as Saturn, but half the size. The Red
Planet continues to head for the eastern horizon and appears 11° high at Dawn
and 23° high at Civil Dawn. Dwarf planet Ceres, also in Aquarius, rises at 3:18
AM, 8° East of Mars, 18° high and an easy 8th magnitude. Neptune now makes its
appearance in the Dawn sky, sharing Aquarius, it rises at 3:21 AM, glowing with
8the magnitude, but a tiny 2 arc-seconds in size. Finder charts for Ceres and
Neptune are available from astronomy websites.
Ceres was the first asteroid discovered. It was discovered on Jan 1, 1800. Ceres was the Roman goddess of agriculture and taught humans to grow grain. Ceres orbits the Sun about midway between Jupiter and Mars. It is the largest asteroid, about 600 miles across.
There is a lot of confusion about asteroids. The “asteroid belt” is usually pictured in movies as an almost solid belt of huge rocks. Actually, there are many thousands of miles between rocks of varying sizes. Scientists think they know the composition of some asteroids,
from meteorites. Several spacecraft are on the way to study asteroids, and others
are in various stages of planning.