For October, the waxing crescent moon
passes bright Jupiter on October 3rd. It is
first quarter on October 5th, to the lower
right of Saturn. Full moon, the Hunter’s Moon,
is October 13th. Last quarter is October 20th.
New Moon is October 27th, which means that by
Halloween, the waxing crescent moon will again
be close to Jupiter right after sunset for a
telescopic treat for the neighborhood kids, so
get out the telescope and the Milky Way bars.
We can see the two inner planets, Mercury
and Venus, low in the SW about 40 minutes
after sunset on October 22nd. Venus will be to
the right and much brighter; get a site that
has a flat SW horizon to spot them. Mercury
soon passes between us and the Sun on November
11th, a transit that will be visible from
here. More on it next month! Venus continues
to pull away from the Sun for the rest of
2019, getting higher and brighter in the
western evening sky each night.
Mars returns to the dawn sky just before
sunrise by months end. Jupiter and Saturn are
both well placed for observation in the
southwest evening sky this month, but look for
Venus to overtake Jupiter in the twilight in
November. Jupiter in Ophiuchus will get lost
also getting lost in the sun’s glare by
Thanksgiving, Saturn is still out in
Sagittarius in the SW, but also will be gone
by Christmas, leaving Venus the only evening
planet by New Years.
While the naked eye, dark adapted by
several minutes away from any bright lights,
is a wonderful instrument to stare up into
deep space, far beyond our own Milky Way,
binoculars are better for spotting specific
deep sky objects. For a detailed map of
northern hemisphere skies, about September
30th visit the www.skymaps.com website and
download the map for October; it will have a
more extensive calendar, and list of best
objects for the naked eyes, binoculars, and
scopes on the back of the map.
The Big Dipper falls lower each evening. By
the end of October, it will be only the three
stars in the handle of Dipper still visible in
the northwestern twilight. By contrast, the
Little Dipper, while much fainter, is always
above our northern horizon here along the Gulf
Coast.
To the southwest, Antares and Scorpius also
set soon after twilight, and will be gone by
month’s end. East of the Scorpion’s tail is
the teapot shape of Sagittarius, which marks
the heart of our Milky Way galaxy. Saturn lies
above of the pour spout now. Looking like a
cloud of steam coming out of the teapot’s
spout is the fine Lagoon Nebula, M-8, easily
visible with the naked eye. This stellar
nursery is ablaze with new stars and steamers
of gas and dust blown about in their energetic
births. In the same binocular field just north
of the Lagoon is M-20, the Trifid Nebula. Many
other clusters visible in binoculars as you
sweep northward along the Milky Way, and are
plotted on the sky map for the month.
The brightest star of the northern
hemisphere, Vega dominates the sky overhead.
To the northeast of Vega is Deneb, the
brightest star of Cygnus the Swan. To the
south is Altair, the brightest star of Aquila
the Eagle, the third member of the three
bright stars that make the Summer Triangle so
obvious in the NE these clear autumn evenings.
To the east of Altair lies tiny Delphinus, a
rare case of a constellation that does look
like its namesake.
To the east, the square of Pegasus is a
beacon of fall. South of it lies the only
bright star of Fall, Fomalhaut. If the
southern skies of fall look sparse, it is
because we are looking away from our Galaxy
into the depths of intergalactic space. The
constellation Cassiopeia makes a striking W,
rising in the NE as the Big Dipper sets in the
NW. Polaris lies about midway between them.
She contains many nice star clusters for
binocular users in her outer arm of our Milky
Way, extending to the NE now. Her daughter,
Andromeda, starts with the NE corner star of
Pegasus’’ Square, and goes NE with two more
bright stars in a row. It is from the middle
star, beta Andromeda, that we proceed about a
quarter the way to the top star in the W of
Cassiopeia, and look for a faint blur with the
naked eye. M-31, the Andromeda Galaxy, is the
most distant object visible with the naked
eye, lying about 2.5 million light years
distant. It is a bigger version of our own
Galaxy, which it may collide with about three
billion years from now.
Below Andromeda is her hero, Perseus. In
his hand is a star most appropriate for
Halloween, Algol. This star "winks" at us for
six out of every 70 hours, which Arabic
astronomers centuries ago found spooky, hence
naming it "the ghoul". We know today it is an
eclipsing binary system, with the larger,
cooler orange star covering 80% of its
smaller, hotter neighbor during the "wink". At
the foot of Perseus, the hero of "Clash of the
Titans" is the fine Pleiades star cluster, the
"seven sisters" that reveal hundreds of
cluster members in large binoculars. This
might be the best object in the sky for
binocular users.
Winter will be coming soon, and in the NE
we see yellow Capella rising. It is the
brightest star of Auriga the Charioteer, and
pair of giant stars the same temperature as
our sun, but at least 100X more luminous and
about 10X larger than our sun. It lies about
43 light years distant. A little farther
south, below the Pleiades, orange Aldebaran
rises. It is the eye of Taurus the bull, with
the V shaped Hyades star cluster around it
making the head of the bull. This colorful
giant star is only 2/3 as hot as our yellow
sun, but 44X times larger and at 65 light
years distant, one of the closest of these
monster stars.