This month’s
star chart shows the continuing parade of the planets at 7:00 PM on March
13. Sunset is at 7:01 PM, so the sky will still me rather bright
at the time shown. With binoculars, you may be able to see Mercury
about 10 deg above the horizon shining at about 2.6 mag before it sets
at 7:48 PM. Jupiter (-2.1 mag), Venus (-4.0), and lovely Saturn (1.9)
will then claim our attention. Venus is the third brightest object
in the sky, after the sun and moon.
Notice that
the magnitudes of the brightest objects are negative. In the 2nd century
AD, Ptolemy assigned magnitudes ranging from 1 for the brightest stars
through 6 for the dimmest stars visible to the unaided eye. To better differentiate
the really bright 1st magnitude objects, we have come to use negative
numbers for the really bright stars and planets. Maybe you can devise a
better magnitude scale!
The Double Cluster
in Perseus is a great binocular object about 8:30 PM, located about 35
deg above the NW horizon. These objects also show up well at low
power in a scope.
You can print a copy of this star
chart so you can take it outside.
