158ASTRONOMY
every hour. This is because it orbits
eastward around Earth about
15 degrees every day opposite to the
motion of the celestial sphere. (You
can see this by watching it pass a
bright star during an evening.) If you
live in Southern Canada, applying
the sunrise/sunset correction to the
times of moonrise and moonset will
put you within 10 to 20 minutes of the
actual time. Occasionally, an entry
is blank when moonrise or moonset
is after midnight. In those cases, it
appears on the line of the next day.
Notable events column
This column will make you aware
of various other celestial events
and help you identify specific stars,
planets and celestial objects. We give
the time for the celestial events in
a 24-hour format (hh:mm). These
events only need your time zone
correction. To differentiate the
local horizon- and meridian-related
events, we use an a.m. and p.m.
format and require both time zone
and city corrections to be applied.
The “notable events” column lists
the day the sun crosses constellation
boundaries and the lunar phases.
The lunar cycle begins at new moon,
then it passes through first quarter at
about seven or eight days of age, full
moon at about 15 days of age, and last
quarter (or three-quarters) at about
21 days old. The moon passes through
its cycle in 29.5 days. The moon’s age
in days is a convenient way to mark
the phase. The lunar phase occurs
at the same moment in Vancouver
as in Ottawa—so it only needs to be
corrected for your time zone.
OTHER TABLES
The other tables list information on
interesting celestial phenomena and
objects. These include lunar eclipses
and meteor showers. If it is cloudy,
there are no re-runs. Sorry.
There is a table for the lunar
phases. Since the planets are usually
some of the brightest objects at night,
we list their major orbital phenomena
so you can begin to imagine their
place in our 3D solar system.
When the planet is at opposition,
it is opposite the sun in our sky—at
roughly midnight in standard time.
(The sun and the object in opposition
are not visible in the sky at the same
time.) At conjunction, the planet
is along a line passing through the
sun and Earth. When the planet
is between Earth and the sun, it is
called an inferior conjunction; a
superior conjunction is when the
planet is beyond, or behind, the sun on
the other side of the solar system.
The elongations are when Mercury
and Venus appear farthest from the
sun in our sky, after they have orbited
out from behind the sun (western
elongation in the morning), or are
about to orbit around behind the sun
(eastern elongation in the evening).
We also provide reference tables
for the constellations by season and
the brightest stars.TIDES ALONG THE
CANADIAN COASTS
The Canadian Hydrographic Service
publishes tide tables for many
marine harbours on the Atlantic,
Arctic and Pacific oceans. These are
available at tides.gc.ca and can be
accessed for free during the year of
their use (2020).I hope your skies will be clear and
you will enjoy your astronomical
almanac. Have a great 2020!