Caribbean Compass Yachting Magazine - December 2021

DECEMBER 2021 CARIBBEAN COMPASS PAGE 26
THE CARIBBEAN SKY: FREE SHOW NIGHTLY!
The Sky from Mid-December to Mid-January
by Jim Ulik
The launch of the James Webb Space Telescope is scheduled for December 18th
from Kourou, French Guiana. Of course, it is dependent upon a good weather
window. If the launch window opens at night there may be a chance for those with
a clear view of the horizon from east Trinidad or Tobago to spot the rocket leaving
Earth’s atmosphere. It might be possible to see the Ariane 5 rocket plume or exhaust
up to 600 nautical miles away when it reaches 60 miles above Earth. Added to the
visual distance is the viewing height of the observer. A person six feet tall would add
another 2.87 nautical miles. The formula used to calculate the visual distance is the
square root of height X 1.17 = distance to the horizon in nautical miles.
This is all an exercise in viewing possibilities. One variable, the rocket is launched
in the direction of Earth’s rotation and orbit around the Sun. A rocket launched near
the equator will get an initial boost of 1,675 kilometers per hour (1,041 miles per
hour) equal to the velocity of Earth surface. While the rocket arcs eastward any
location on Earth also rotates in the same
direction allowing some potential to keep an
eye on the rocket.
Thursday, December 16th
Mars is rising early this morning just out of
reach from the claws of Scorpius. In the
predawn sky there may be a shooting star or
two from the Comae Berenicid meteor shower.
This shower peaked overnight and may
produce its best displays shortly before dawn.
The Comae Berenicid shower will be active
December 12th to 23rd.
Comet C/2021 Leonard may become visible
in the western sky shortly after sunset this
evening. Even though it is potentially bright
enough to be seen with the naked eye, a pair
of binoculars may be required to spot the
comet. The comet is located between Mercury
and Venus. Over the next few days it will
become less bright as it shifts left of Saturn.
See Image 3. The incoming comet was
discovered in January 2021. It reached its
closest point to Earth on December 12 but not
visible because it was lost in the glare of the
Sun. The comet is destined to make its closest
approach to the Sun on January 3rd, 2022.
Saturday, December 18th –
Sunday, December 19th
The Moon will transition into its full phase
just after midnight. The Moon is 180 degrees
away from the Sun’s ecliptic longitude, as
observed from the center of the Earth.
Taurus, Orion and Gemini will carry the
Moon across the night sky until sunrise.
Monday, December 20th
The December Leonis Minorid meteor
shower is active from December 5th through
February 4th. This shower may peak tonight,
but the best dates to spot any meteors will be
before December 14th or after January 1st
when there is no interference from moonlight.
Meteors will radiate out of an area between
Leo and Leo Minor.
IMAGE 2 ESA - D. DUCROS
Tuesday, December 21st
Today is the darkest day of the year in the Northern Hemisphere. The Sun is
directly over the Tropic of Capricorn in the Southern Hemisphere. Like it or not,
today is the winter or December solstice.
There is a conjunction between the Moon and Pollux tonight. The pair can be seen
in the eastern sky around 2200 hours. The yellow orange star is located below or
east of the Moon. Pollux is almost nine times the diameter of the Sun and about 30
times the Sun’s brightness in visible light. The planet orbiting Pollux has over two
times the mass of Jupiter.
Thursday, December 23rd
The Ursids meteor shower produces shooting stars from December 17th to
December 26th.
—Continued on next page
James Webb Space Telescope leaving Earth for its 1.5 million kilometer
(1 million mile) journey.