The
purpose of this feature is to give scout leaders, educators and naturalists an
idea of some of the natural events coming up each month. We will try to
cover a variety of natural events ranging from sky events to calling periods of
amphibians, bird and mammal watching tips, prominent wildflowers and
anything else that comes to mind. We will also note prominent
constellations appearing over the eastern horizon at mid-evening each month for
our area for those who would like to learn the constellations. If you have
suggestions for other types of natural information you would like to see added
to this calendar, let us know!
Though we link book references to nationwide sources, we encourage you to
support your local book store whenever possible.
Notes From September 2022
Askar FRA 400 Astrograph on ZWO Mounting
The last couple of weeks in September brought cool sunny days and
dark skies to Lookout Mountain. I recently purchased a small astrograph to
take some wide-angle shots of the sky and I was happy to get a chance to
try it out. The astrograph is an Askar FRA 400, which consists of a
four-element Petzval lens design plus a field-flattener. The Petzval
design is about one hundred and fifty years old and was originally
designed for portrait lenses. It's had quite a run!
The camera, filter wheel, mounting and tripod are by ZWO Optical Company.
The tripod is carbon fiber, and the whole assembled telescope can be
picked up and moved around if needed. The drive for the mounting is a
relatively new
type of drive called a
harmonic drive. As you can see from the image
at right, it
needs no counterweight! Both the telescope and mounting are very precisely
made, and the
performance is appropriately heavenly. In the image at right the telescope
is coupled to a ZWO filter wheel and camera. Partly visible is a small
guide telescope and camera, and beneath the tube there is a small
processor that choreographs the scope's movements throughout the night
without outside input. The plan for the night is entered into the
processor
via an app on my cell phone.
I spent many pleasant evenings in a lounge chair beside the scope in my
backyard, using my binoculars to hunt for various galaxies and clusters.
Once started, the telescope automatically focuses, changes filters, guides
itself and flips over to the other side of the tripod when it reaches the
zenith.
Since the moon was still bright on September 12th, I decided to use
narrow-band filters for my first image. These filters allow only a very
small slide of the spectrum to reach the camera, and so are not affected
very much by moonlight as would typical red, green and blue filters. I
chose the large patch of nebulosity in Cepheus known as the Elephant's
Trunk Nebula. This image primarily shows vast clouds of glowing hydrogen.
The Elephant's Trunk Nebula, September 12th - 18th, 72mm Askar
FRA 400 Astrograph.
The brightest parts of the nebula are about three degrees
across in the
image above. That means that if it were bright enough to see with the
naked eye in the night sky, you could fit six full Moons across its
diameter. Across the nebula there are dark patches of dust and gas that look like mutant tadpoles swimming
through the nebulosity. The "elephant's trunk" extends from bottom right
towards the center of the nebula.
The Elephant's Trunk nebula is about 300 light-years in diameter and about
3,000 light-years distant. The star at top right is Mu Cephie, a red
supergiant. It is one of the largest known stars in our galaxy. If you
were to put it in place of our sun, its radius would extend outward to
somewhere between the orbits of Jupiter and Saturn!
At right is a diagram showing the relative sizes of the Sun and planets.
The Sun comprises 99.8 percent of the total mass of the solar system. The
planet Jupiter is responsible for 2/3rds of the remaining mass. The Earth
is only about 1/330,000 of the mass of the Sun.
Now consider that one billion Sun's
would fit inside of Mu Cephei!
Mu Cephie is also known as Herschel's Garnet Star. The deep orange-red
color may not be obvious to the naked eye, but binoculars bring out the
color well. The constellation Cepheus is well placed for viewing in the
evening sky now
By September 23rd I could take images without the Moon present,
so I decided to take a natural color image of the Andromeda Galaxy,
Messier 31. One of the very first things I do on cool
fall evenings is to take a quick look at Messier 31 to check the
transparency of the sky. On a good night M31 is easy to see with the naked
eye. On a mediocre night it may be only seen with averted vision (looking
to one side of the galaxy rather than right at it) and in light-polluted
areas it may not be visible at all. Its position is shown on the
constellation charts for last month's Natural Calendar.
Don't expect to see the detail and colors in the image below.
Most deep sky objects like M-31 just give you hints of their
grandeur in visual views. The galaxy
was first shown in the "Book of Fixed Stars" by Persian astronomer Al-Sufi
in AD 964. He referred to it as "the little cloud", and that's exactly
what it looks like in the night sky; a faint colorless, oval glow. Simon
Marius, a contemporary of Galileo, has one of my favorite descriptions of
the way it looks in a small telescope or binoculars. He described its
appearance as, "the light of a candle shining through horn".
Although its apparent size in the night sky is about the same as the
Elephant's Trunk Nebula, the Andromeda Galaxy is much more distant, about
2,600,000 light-years away. When you looking at it you are looking at
ancient light. To appreciate the scale, look at the outer spiral arms in
the image below. You will see tiny reddish spots along the arms. Those
spots are in reality areas of glowing hydrogen comparable to the
Elephant's Trunk Nebula shown above.
The Great Andromeda Galaxy, September 23rd, 72mm Askar 400
Astrograph
Also seen in the image are two of the brighter satellite galaxies of
Messier 31, Messier 32 above and to the left of the core and Messier 110 below.
My final night of viewing was on September 28th. The wind was blowing hard
and it didn't appear to be a good night for imaging. But the sky was
the clearest I've ever seen it here. There was the usual feeling I get on very clear nights that there was an extra layer of
stars added to the my normal views. But the dark rift in the Milky Way was
very, very dark. The "Northern Coalsack", a dark nebula near the bright
star Deneb at the tail of the swan, was indeed looking like a coalsack. I
have never seen it like that before.
I raised my 10x30 image-stabilized binoculars to look at the Andromeda
Galaxy. To my surprise both of the satellite galaxies were visible with
averted vision, something I haven't seen in those binoculars for a long time. Most of the time,
even on good nights, I can only see M-32, the brighter satellite galaxy
that is closer to the core of M-31. It was a nice end to the evening.
Sky Events for October 2022
The Orionid Meteor Shower peaks in the morning hours of October
21st.
Mars, June 11th, 2016. 20" Newtonian Reflector and ZWO ASI
120MMS camera.
Morning Sky:
Venus
will continue to rise before the Sun, but it will sink lower and
lower into the morning twilight each day. Venus will disappear into the Sun's glare around the
middle of October. Mercury reaches greatest elongation from the
Sun on October 8th. Look for it about 40 minutes before sunrise
low in the eastern sky. A flat eastern horizon will help as will a
pair of binoculars. Put your binoculars up at sunrise to avoid
permanently damaging your eyes.
Evening Sky:
Look for bright Jupiter in the eastern sky after sunset in Pisces,
below the "square of Pegasus". Saturn transits about 3 hours after
sunset in Capricornus. Mars rises about 3 hours and 45 minutes
after the sunset in Taurus. Mars and Aldebaran, the red eye of the
bull, make a striking pair! This is a great time to start
observing Mars. Mars comes to opposition in December. The red
planet is appearing large enough to show some details to patient
observers using small telescopes.
Constellations:
Able 39, June 6th,
2016, a faint planetary nebula in Hercules. Note the faint
galaxies that can be seen through the nebula!
The views below show the sky looking east at 10:15pm EDT on October
15th. The first view shows the sky with the constellations outlined
and labeled. Star and planet names are in green. Constellation
names are in blue. The second view shows the same scene without
labels. Prominent constellations include
Triangulum, the Triangle,
Aries,
the Ram, and
Cetus,
the Sea Monster.
Auriga, the Charioteer,
with its bright star
Capella,
and
Taurus,
the Bull,
are rising in the northeast. The bright star
Aldebaran,
a red giant representing the eye of the bull, should just be rising.
Above Aldebaran, look for the
Pleiades,,
a beautiful open star cluster. Also called the "Seven Sisters," it
has been known since antiquity. In Japan it is known as Subaru, and
the Subaru automobile is named for this cluster. Before the
Gregorian calendar reform in 1582, the Pleiades culminated around midnight
on October 31st, and it has been traditionally associated with Halloween.
Clear
moonless fall nights are a great time to hunt down deep sky objects in Cygnus.
The constellation is just about directly overhead and objects like the
Veil Nebula or the Cocoon Nebula are at their best. Don't expect to see
the bright colors that long-exposure CCD images capture.
October 15th, 10:15pm EDT, Looking East
October 15th, 10:15pm EDT, Looking East
On Learning the
Constellations:
We advise learning a few constellations each month, and
then following them through the seasons. Once you associate a particular
constellation coming over the eastern horizon at a certain time of year, you may
start thinking about it like an old friend, looking forward to its arrival each
season. The stars in the evening scene above, for instance, will always be
in the same place relative to the horizon at the same time and date each
October.
Of course, the planets do move slowly through the constellations, but with
practice you will learn to identify them from their appearance. In
particular, learn the brightest stars for they will guide you to the fainter
stars. Once you can locate the more prominent constellations, you can
"branch out" to other constellations around them. It may take you a little
while to get a sense of scale, to translate what you see on the computer screen
or what you see on the page of a book to what you see in the sky. Look for
patterns, like the stars that make up the constellation of Perseus.
The earth's rotation causes the constellations to appear to
move across the sky just as the Sun and the Moon appear to do. If you go
outside earlier than the time shown on the charts, the constellations will be
lower to the eastern horizon. If you observe later, they will have climbed
higher. To observe faint objects, it's always better to wait until they
are high in the sky.
As each season progresses, the earth's motion around the sun
causes the constellations to appear a little farther towards the west each night
for any given time of night. The westward motion of
the constellations is equivalent to two hours per month.
A good book to learn the constellations is
Patterns in the Sky, by Hewitt-White.
For sky watching tips, an inexpensive good guide is
Secrets of Stargazing, by Becky Ramotowski.
A good general reference book on astronomy is the Peterson
Field Guide,
A Field Guide to the Stars and Planets, by Pasachoff. The book retails for around $14.00.
The Virtual
Moon Atlas is a terrific way to learn the
surface features of the Moon. And it's free software. You can
download the Virtual Moon Atlas here.
Apps:
The Sky Safari 6 basic version is free and a great aid for
the beginning stargazer. I really love the
Sky Safari 6 Pro. Both are available for iOS and
Android operating systems. There are three versions. The Pro is
simply the best astronomy app I've ever seen.
The description of the Pro version reads, "includes over 100 million stars, 3 million galaxies
down to 18th magnitude, and 750,000 solar system objects; including every comet
and asteroid ever discovered."
You may also want to try the very beautiful app
Sky Guide.
Though not as data intensive as Sky Safari, Sky Guide goes all out
to show the sheer beauty of the night sky.
Great for locating the planets.
A
nother
great app is the Photographer's
Ephemeris. Great for finding sunrise, moonrise, sunset and
moonset times and the precise place on the horizon that the event will
occur. Invaluable not only for planning photographs, but also nice
to plan an outing to watch the full moon rise. Available for both
androids and iOS operating systems.
Amphibians:
Southern Leopard Frog
When the evening temps begin to drop, listen for
Southern Leopard Frogs calling during their fall breeding period.
Listen also for
Spring Peepers
to call from patches of
woods.
Upland Chorus Frogs sometimes give a very dry, raspy version of their
call in October. Warm-weather species like treefrogs seldom call now, but
you can sometimes find them foraging in trees and shrubs. You can locate many of the frogs and toads that have been calling more
frequently earlier in the year by driving the back roads slowly on rainy nights.
This is a two person job. One person watches the road for amphibians and
one person looks out for other vehicles. Continue to look for salamander
species that breed in the fall, like the Marbled Salamander. Recommended: The Frogs and Toads of North America,
Lang Elliott, Houghton Mifflin Co.
Nature Notes Archives: Nature Notes
was a page we published in 2001 and 2002 containing our observations about
everything from the northern lights display of November 2001 to frog and
salamander egg masses.
Night scenes prepared with The
Sky Professional from Software Bisque
