Tip:
Highlight text to annotate it
X
Salutations celestial sight seers! I'm David Fuller, welcome to Eyes on the Sky; what's
up this week?
Autumn is an interesting season -- wait, what? It's that time already!?!?! Oh, I guess it
is! On September 22 at 20:44 UTC, Earth reaches autumnal equinox for the Northern Hemisphere.
What's fascinating about autumn for astronomy is that we get extra time to view some of
the summer sights. Let's look west: Note where the three stars of the Summer Triangle are
at midnight on September 22. But because days get shorter and nights get longer, let's fast
forward to the winter solstice, December 21-st at 6 pm. All three stars have only dropped
to 10 degrees to the west! So even though there's quite a time difference, the "Summer
Triangle" is still visible at the beginning of winter!
But, many of us lose all the wonderful clusters and nebula of Sagittarius and Scorpius in
the south, replaced by Pisces Austrinus, which only offers the first magnitude star Fomalhaut
as a beacon in that part of the sky. Between the Summer Triangle and there are the somewhat
dimmer constellations of Capricornus and Aquarius, both part of the "water constellations" like
Pisces Austrinus also is. These two constellation names may sound familiar, as they are part
of the zodiac since the ecliptic runs through them, and we can find Neptune in Aquarius,
and Uranus in the dim Pisces the Fish to its east. Cetus the Whale -- or Sea Monster - rounds
out most of the large, mostly dim, water-themed constellations here.
Dark Sky Fact: In the United States alone, 2.2 billion dollars is wasted on light that
doesn't even light up the ground. Use lower wattage lighting that is aimed and shielded
at the ground, so you can save money and still see at night - including the stars overhead.
Rising in the east and moving towards overhead, we find somewhat brighter 2-nd magnitude stars,
and many of these can be found by knowing how to measure 15 degrees in the sky (and
estimating 20 degrees from that). Pegasus the Flying Horse is one of the more obvious
ones, the flying horse's wings forming a near perfect square, or diamond, in the sky, as
its stars are almost perfectly 15 degrees per side. Off the western side of this foursome
is Enif, the nose of the horse, at 20 degrees away. On the opposite side are the stars of
Andromeda the princess, and the stars Mirach and Almaak are nearly a perfect 15 degrees
from the square. Continue another 15 degrees in the same direction and we run right into
the star Mirfak in Perseus the hero. Rising near the horizon, if we follow somewhat along
that same line, is Capella, one of the brightest stars in the sky, in the constellation Auriga.
Double our 15 degrees and we find the orange-ish Aldebaran in Taurus towards the south, with
the lovely Pleiades 15 degrees away preceding the red giant across the sky. And rounding
out the autum sky to the north are Cassiopeia the Queen and Cepheus the King. The distinctive
"W" shape of the queen is hard to miss about 20 degrees to the northwest of Mirfak in Perseus,
though look for Cassiopeia on her side, or perhaps a bit more "M" shaped at this time
of year. Cepheus is dimmer, looking like an upside-down house shape. We'll explore many
of these stars and constellations over the next three months, so now is a great time
to get familiar with where to find all of them. (BREAK) With the Moon full on the 19-th,
many deep sky objects will be challenging to observe easily. (Break) But the first,
second and third magnitude stars of these shapes shouldn't be too hard to find.
Along The Ecliptic: As we wave goodbye to useful evening telescopic observations of
Saturn for the year, Venus makes one last stop by the planet this week. Meanwhile Jupiter
reaches a useful observing altitude by 2 or 3 in the morning, with the still small Mars
following it about two hours later. That leaves the evening sky largely devoid of bright planets,
Neptune angling across Aquarius and Uranus puttering past Pisces, while the Moon cruelly
makes it difficult to see either one this week.
That's all for this week. Keep your eyes on the sky and your outdoor lights aimed down,
so we can all see, what's up. I'm David Fuller, wishing you clear and dark skies.