Volume 14 • Issue 8
October 2015
ISSN 1712-4425
peterboroughastronomy.com
twitter.com/PtbAstronomical
The Reflector
Newsletter of the Peterborough Astronomical Association
Measure the moon’s size and distance
during the next lunar eclipse
Image credit: Daniel Munizaga (NOAO South/CTIO EPO), using the Cerro Tololo Inter-American Observatory, of an eight-image sequence of
the partial phase of a total lunar eclipse.
Ethan Seigel
T
he moon represents perhaps the first great paradox
of the night sky in all of
human history. While its angular
size is easy to measure with the
unaided eye from any location on
Earth, ranging from 29.38 arc-minutes (0.4897°) to 33.53 arc-minutes
(0.5588°) as it orbits our world in
an ellipse, that doesn’t tell us its
physical size. From its angular size
alone, the moon could just as easily
be close and small as it could be
distant and enormous.
But we know a few other things,
even relying only on naked-eye observations. We know its phases are
caused by its geometric configuration with the Sun and Earth. We
know that the Sun must be farther
away (and hence, larger) than the
moon from the phenomenon of
solar eclipses, where the Moon
passes in front of the Sun, blocking
its disk as seen from Earth. And we
know it undergoes lunar eclipses,
where the Sun’s light is blocked
from the Moon by Earth.
Lunar eclipses provided the first
evidence that Earth was round; the
shape of the portion of the shadow
that falls on the moon during its
partial phase is an arc of a circle. In
fact, once we measured the radius
of Earth (first accomplished in the
3rd century B.C.E.), now known to
be 6,371 km, all it takes is one assumption — that the physical size
of Earth’s shadow as it falls on the
moon is approximately the physical size of Earth — and we can use
lunar eclipses to measure both
the size of and the distance to the
Moon!
Simply by knowing Earth’s physical size and measuring the ratios
of the angular size of its shadow
and the angular size of the Moon,
we can determine the Moon’s
physical size relative to Earth. DurSee “Measure the Moon” on page 16
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President’s Message
T
A Quieter Time for the PAA
he paa did not have a lot of outreach activity this September. On
September 25th we did go to the
Peterborough Museum & Archives for an
evening with the Canadian Family Health
Collective’s “Family Wishes Event.” We had
a number of telescopes set up with line-ups
at every station as there was a huge crowd
of people.
Individually, a number of our members
added to or upgraded equipment. This
included two iOptron Mini Tower Pro’s,
a Mini Tower II and a Cube G. Two more
Vixen VMC200L OTA’s have been added
and an Orion 10” Intelliscope has changed
S
hands. We saw most of this equipment in
use at the “Family Wishes Event.” Congratulations to all on their new equipment acquisitions.
As I write this we look forward to a glorious total lunar eclipse happening on Sunday, September 27th. I’m sure we’ll see lots
of photo coverage of this event.
Don’t forget election time is drawing
near. Please consider putting your hand up
for an executive position.
Rodger Forsyth
PAA President
Loony Lunacy
uper Moons are over-rated; most of
us wouldn’t notice any difference
despite media hype. Now, make the
Super Moon a total lunar eclipse and the
pandemonium spreads. While clouds did
veil the event, some of us were fortuate to
catch a glimpse during the first umbral
phases and the totality. I have to say totality
was darker than I had previously observed
but I wonder if the cloud cover had some
effect.
Is it crazy to dedicate almost an entire issue to lunar subjects? Not as crazy
as devoting almost an entire issue to the
wordsmithing of one John Crossen. Seriously, John writes far and wide on a variety
of lunar matter and it is a fitting issue to
celebrate all things lunar in honour of a
wonderful lunar eclipse last month.
Rick Stankiewicz has a great summary of
last weekend’s lunar eclipse with stunning
photo for illustration. Also in the Gallery,
John Chumak provides an annotated photo
of the Seven Sisters, a.k.a. M45, the Pleiades
Star Cluster.
And to end off, in the immortal words of
Duran Duran:
I light my torch and wave it for the
New moon on Monday,
And a fire dance through the night.
I stayed the cold day with a lonely
satellite.
Phillip Chee
Editor, The Reflector
The Reflector
The Reflector is a publication of the Peterborough Astronomical Association (P.A.A.) Founded in 1970, the P.A.A. is your local
group for astronomy in Peterborough and the Kawarthas.
www.peterboroughastronomy.com • [email protected]
Phone: 705.292.0729
Club Mailing Address
Rodger Forsyth, President
Peterborough Astronomical Association
536 Robinson Road RR #1
Peterborough, ON K9J 6X2
Vo l 1 4 • I s s u e n o. 8 • O c t o b e r 2 0 1 5 •
PAA Makes Wishes
on a Star Come True
3
John Crossen
T
he P e t er borough Astronomical Association was delighted to once
again be invited to show kids and
adults some of the mysteries of outer space.
The near full Moon was a hit with everyone
as they saw close up the craters and huge
lava flows that make up the face of the
Moon. paa members were busy answering
questions about how old the Moon was and
where it came from.
Saturn also captured the imaginations of
young and old. The rings presented themselves beautifully. And as a bonus, everyone
marveled at its moon system. The viewers
were lucky because Saturn will soon be lost
in the sunset’s glare. We’ll see it again, but
it won’t be for another few months when it
becomes an early morning target.
See “Wishes on a Star” on page 15
The Reflector
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Pluto
The Dwarf Planet with Big Surprises
“The Heart” on Pluto is a relatively flat expanse of ice. It is also called the Tombaugh Region after Pluto’s
founder, Clyde Tombaugh. Image by NASA New Horizons.
Johhn Crossen
A
lot of astronomers thought that
when the New Horizons spacecraft
finally arrived at Pluto we’d find a
cold, dead planet. Call it a cosmic gravestone marking the outer limits of our solar
system... Instead we found just the opposite.
At -233 degrees Celsius, Pluto is definitely
a cold world. But one look at the mountains and vast plains showed that Pluto was
also one geologically active puppy — far
from dead. This wasn’t expected and the
questions as to how and why have already
sparked some active debate.
Here on Earth mountain ranges have
been caused by tectonic plate move-
ments — one land mass pushing on another. The weaker of the two either is pushed
up to form a mountain chain or down
where it eventually is reheated and recycled
in to Earth’s molten core. The San Andreas
Fault line is a good example of this. Meanwhile on the opposite side of the world the
Himalayan Mountains have been pushed up
thanks to the tectonic plate collision between Tibet and India. But what caused the
mountains on Pluto?
At the moment some scientists think that
radioactive decay at Pluto’s core may be the
reason. That’s what causes plate movement
here on Earth, but Pluto is such a small body
See “Pluto” on page 15
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5
October Means Planets Galore and
a Meteor Shower
John Crossen
O
ctober is a planet hunter’s
paradise. Jupiter, Venus and Mars
rise about an hour before the
Sun’s glow erases the night from the sky.
Throughout the month the trio is getting
closer and closer together. On October 28th
the threesome form a tight triangle in the
hind legs of the constellation Leo.
Venus will be the brightest of the three
followed by Jupiter and tiny Mars. It will
make a great photo-op for the camera brigade. But the three-planet conjunction isn’t
the only planetary attraction.
In the southwestern sky is Saturn. The
ringed beauty will be available at dusk, a
much more reasonable hour. Look for it
near the bright star Antares in the constellation Scorpius. You can spot Saturn naked
eye, but to see the rings you’ll need a telescope operating at 30 times magnification.
Right behind Saturn lurks Pluto in Sagittarius. It’s a telescopic sight only and
you’ll need a big scope, too. Being a 14th
magnitude target, you’ll need eight-inches
(200mm) of aperture at the minimum and
you must have a very dark sky. To find Pluto
I suggest Googling up www.space.com to check
out their map.
Uranus will be precisely opposite the
Sun on the night of October 11-12. It’s an
event known as opposition. As the Sun sets,
Uranus will rise. By around 10:00 it should
be out of the atmospheric soup near the horizon. It will be visible, but you’ll need super
acute vision and a very dark sky. Shining at
magnitude 5.7, it is near the limit of visibility for most of us. A pair of binoculars
will reveal the distant blue-green dot more
easily. It is currently in the constellation
Southern Pisces, also known as the Southern Fish.
Those with a yen for meteor showers will
be treated to the Orionid Meteor Shower in
The constellation Orion is portrayed as a fierce hunter.
However, despite his weapons and nasty spirit, he fell
prey to a tiny scorpion. Orion was also reported in
ancient myth to be a womanizer who is chasing the
Messier Object known as the Seven Sisters of the Pleiades across the sky.
the wee hours of October 21 – 22. Emanating from the constellation Orion they will
put on a fine show (15/hr) for the following
four hours, until sunrise brightens the sky.
The Orionids are the left-over bits from 1P
Comet Halley.
When comets near the Sun they melt
(sublimate) and leave small rocky bits
behind. If they cross Earth’s orbital path
around the Sun, we collide with their
leave-behinds and enjoy a meteor shower.
The meteors are usually about the size of a
peanut and burn up harmlessly in Earth’s
atmosphere. Larger hunks, say the size of a
baseball, are vastly brighter and are known
as fireballs. They often light up the ground
and leave a smoking trail in the night sky.
To watch a meteor shower takes nothing
more than your eyes. Telescopes and binoculars narrow your field of view to the point
they are useless. So settle back in a comfortable chair with a view to the east and watch
the show as Orion rises.
Those are the celestial highlights for October. Clear skies to everyone.
The Reflector
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There are Astronomical
Falsehoods in the Hood
Saturn’s rings may look solid through a telescope on Earth, but they’re really trillions of ice chunks orbiting the
planet.
John Crossen
L
et ’ s j um p out to the asteroid
belt. Anyone who has watched a 1950s
sci-fi flick might get the idea that the
asteroid belt is thick with rocky hazards.
But that’s just for looks. Asteroids average
around 600,000 km apart — more than the
distance to the Moon!
Will planetary alignments tear Earth
apart? Will the oceans rise, earthquakes ravage continents and humanity be destroyed?
No. The Earth as we know it is at least 3
billion years old. In that time the planets
have lined up in all kinds of configurations — and Earth is still puttering along.
At the distance the planets are from Earth,
their gravitational affect is close to zot.
Even if all the planets lined up and exerted
maximum gravitational pull on Earth it
would be about the same as the Moon’s tidal
force.
The Sun will bring life on Earth to an
end. But it won’t be with a supernova megabang. Instead the Sun will expand until
it engulfs all the planets out to Jupiter. At
that point it will simply dissipate and leave
behind a glowing nebula to mark our solar
system’s grave. It’s coming in about 3 billion
years. Reserve your seats now.
If you think the Sun would look like just
another star from Pluto you need to get out
more often — way out. The average day on
Pluto is almost as bright as Earth at twilight. So despite the fact that it takes nearly
5.5 hours for sunlight to reach the puppy
planet, it does light the place up — at least a
little.
Astronomers call Jupiter and Saturn “gas
giants.” But it’s not because they’re gas
straight through. They’re referring to the
incredibly thick outer atmosphere of cloud
cover. Deep beneath their outer layer Jupiter and Saturn have solid cores. The same
also goes for Uranus and Neptune. This
duo is frequently referred to as “ice giants.”
But that’s also misleading. Again they have
See “Saturn” on page 15
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7
Records In Space
CHRIS HADFIELD ABOARD MIR SPACE STATION. Canadian Astronaut Chris Hadfield plays a collapsible guitar he
took on his visit to the Russian Mir Space Station. Image from the Lampton Daily Shield.
John Crossen
a dog named Laika into space. The dog was
the first-ever live passenger to make it into
very now and then it’s nice to
review who did what first or longest space. The Russian pooch didn’t return, but
or highest. It’s a history review for us was part of the first experiment performed
space geeks. So here goes with a list of space in space.
On April 12-13, 1961 the Russians did it
records set by different countries. We’ll lead
again
when Yuri Gagarin, a Russian Soviet
off with a foursome of Russian firsts.
In 1957 on October 4 Russia spread panic pilot and cosmonaut, became the first human to journey into outer space. His Vostok
throughout the United States when it sucspacecraft completed one orbit of the Earth.
cessfully launched Sputnik 1, the world’s
A month later Alan Shepherd became the
first man-made satellite. It was a case of
one-ups-man-ship that made the u.s. more first American Astronaut to enter outer
space, but it was a second place finish in
than a tad uncomfortable. While not fightwhat had become “The Space Race.”
ing each other, the two countries were well
John Glenn became the first American to
defined political adversaries.
orbit the Earth on February 20, 1962. ThirtyOn November 3, 1957, the ussr onesix years later, on October 29 of 1998, Glenn
upped the Yanks again with the launch
became the oldest man in space at the age
of Sputnik-2 carrying a dog onboard. The
of 77. His visit to the iss marked a major
Space Age had barely started and just four
triumph for us seniors.
weeks later, the Soviets fired the 508.3-kilogram (1,120.8-pound) spacecraft carrying
E
See “Space Race” on page 13
The Reflector
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Photo Gallery
Total Lunar Eclipse
All week leading up to September 27th it was promising to be perfect weather conditions for the total
lunar eclipse of the largest (closest) Full Moon of the year. At a distance of 356,877 km from Earth, this
would be a true “Super Moon”. All Full Moons are big, but this one was just that much bigger and the
bonus to this Moon is that a couple hours after it appeared over the horizon it would start to slowly
slip into the Earth’s shadow from 9:07 p.m. until 10:11 p.m. when it would be totally “eclipsed”. This
was the plan anyway. Mother Nature had other ideas. It was cloudy most of the evening and it even
rained where I was south of Peterborough. The night was so mild, even the mosquitoes were out!
This was being touted as a “Blood Moon”, but don’t be fooled by all the hype. It was more of a coppery colour. The Moon was in total eclipse for about 72 minutes before reversing the process as it slid
out of the Earth’s shadow, starting at 11:23 p.m. The show was to have wrapped up by 12:47 a.m. on
the 28th. We never got to see all this from around here and I pulled the plug by midnight.
It was definitely worth witnessing this unfold in the night sky. This was one of the darkest lunar
eclipses I have ever seen, given the Moon did not go through the centre of the umbral shadow. If you
missed this event, you will have to wait until January 20th of 2019 to see another eclipse of this kind in
North America. Admittedly we have been spoiled over the last two years with three similar eclipses in
rapid succession between April of 2014 and now this one.
Why or how does the Moon change colour? It is the result of the refraction (bending) of the longer
wavelengths of light (reds and oranges) into the darkest part of the Earth’s shadow, called the “umbra”. Picture the light from all the sunsets and sunrises around the edge of the Earth being reflected
off the surface of the Moon and back to Earth, while you watched this eclipse. Nature at its best!
The beauty is also that you didn’t need big fancy equipment to see or appreciate this event. Just your
bare eyes did the trick.
Rick Stankiewicz
A Luna-tic
All images taken with a Canon 400D camera mounted parafocally on an 8” SCT with iOpteron Mini
Tower II mount. Settings were iso 400, ƒ/6.3 (field flattener) and 6 second exposures (average).
Vo l 1 4 • I s s u e n o. 8 • O c t o b e r 2 0 1 5 •
The Seven Sisters
Hi Everyone,
Everyone’s favorite cluster!!! M45, The Pleiades, a.k.a. “The Seven Sisters” open star cluster in Taurus. Easily
visible to the unaided eye, even from the city, this bright cluster is an amazing view in binoculars or a small wide
angle telescope. M45 is one of the nearest galactic open clusters, sitting about 444 light years away, and shining
at magnitude 1.6. I did also pick up a faint background edge on spiral galaxy, look to the upper left of Electra to
spot it!
M45 is an open star cluster containing middle-aged hot B-type stars located in the constellation of Taurus. It is
among the nearest star clusters to Earth and is the cluster most obvious to the naked eye in the night sky. The
celestial entity has several meanings in different cultures and traditions.
The cluster is dominated by hot blue and extremely luminous stars that have formed within the last 100 million
years. Dust that forms a faint blue reflection nebulosity around the brightest stars was thought at first to be left
over from the formation of the cluster (hence the alternative name Maia Nebula after the star Maia), but is now
known to be an unrelated dust cloud in the interstellar medium, through which the stars are currently passing.
New computer simulations have shown that the Pleiades was probably formed from a compact configuration
that resembled the Orion Nebula. Astronomers estimate that the cluster will survive for about another 250 million
years, after which it will disperse due to gravitational interactions with its galactic neighbourhood.
Greek mythology states that Mighty Atlas (son of a Titan) and his wife, Pleione, had seven incredibly beautiful
daughters. Atlas placed his Seven Daughters in the heavens to protect them from mortal men! And to this day
Orion the Hunter, who is in love with several of the Sisters, follows them around the sky.
[Taken with a] modified Canon Rebel Xsi DSLR and 5.5-inch diameter Vixen Newtonian reflector scope, iso 1600,
for a 76 minute exposure at my observatories in JBSPO in Yellow Springs, Ohio.
Best Regards,
John Chumak www.galacticimages.com
9
The Reflector
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Meet Astronomy’s
Ladies of the Night
Pleiades Star Cluser. Look east and a bit north. The Pleiades will be visible as a faint misty patch. Here we see
Comet Lovejoy zipping past the Seven Sisters. Image taken by Alan Dyer.
John Crossen
I
f there’s one night-sky target
that’ll get your attention this autumn
it’s the Seven Sisters. Also known as the
Pleiades (Play-a-dees/Ply-a-dees), the girls are
an easy naked-eye target. That means you’ll
need no special gear to spot them. You will,
however, need a relatively dark sky overhead. So that leaves downtown Peterborough and most surrounding small towns
out.
If you’re not blessed with a rural location,
get out of town and look eastward about
10:00 p.m. on a clear night. About 45 degrees above the horizon you’ll see our ladies
of the night as a misty patch about the size
of your thumb nail. If you’re in a good dark
sky rural location they’ll pop out quickly to
your dark-adapted eyes. By the way, dark
adapted eyes can see six times better in the
dark, so wait about 20 minutes for your
eyes to adapt to their dark surroundings.
What’s the story behind our celestial sisters? How did they reach their stellar home?
Here’s the mythological lowdown on what
went down.
It seems that the girls were Earth bound
long ago. Unfortunately for them Orion the
Hunter was on the trail of his next meal.
That’s when he spotted them in a forest clearing. Orion had an eye for beauty
and a lust for the ladies. Need I say more?
He instantly shifted gears and began his
romantic pursuit. The ladies didn’t share
his enthusiasm and took flight. As the chase
unfolded the mighty god Zeus looked down.
Seeing that the sisters were in danger, he
turned them into doves and they flew into
the sky where they turned into stars. If you
wait until midnight you’ll see the ConstellaSee “Seven Sisters” on page 13
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11
The Moon Rocks and Rolls
Paritially Eclipsed Moon. September’s Star attraction
isn’t a star. It’s our Moon as it slips into Earth’s shadow
on the night of September 27/28. Thanks to the fact
that it’ll also be a Super Moon, it should cause quite an
attraction in the media. No word from the dooms day
set on whether the Earth will end, too, Image by Fred
Espenak.
Protoplanet Theia Impacting Earth. Summer Stargazing Nightshot. The illustration above shows the Moon being created by an impacting protoplanet 3.5 billion years ago.
John Crossen
L
ogically you’d think that we can
see 50 percent of the Moon’s surface
and that’s it. But you can throw logic
out the window. There’s another littleknown factor that lets us see more than half
of dear old Luna. It’s called “Libration” (not
to be confused with “Libation”) and it’s the
reason we can ultimately see 59-percent of
the Moon’s surface. Libration is the term for
the Moon’s tendency to rock just a little to
the east and to the west and roll a bit north
and south. This rock and roll allows us to
get a peek around the Moons edges to see
just a little more of its surface. To do so, you
have to be an acute observer and follow the
Moon through its complete cycle from New
Moon back to New Moon.
The Moon’s orbit around Earth is elliptical. So sometimes it is closer to us than at
other times. The slight difference in distance changes the observer’s view of the
Moon slightly and shows us just a bit more
of its surface. The cumulative affect is that
we can see 59% of the Moon’s mug.
The Moon’s orbit around Earth is elliptical not a perfect circle. That means that at
times it is farther from us and at others it
is closer. At its farthest point from Earth
it is just a bit over 400,000 km away. At
its closest point it is a bit over 350,000 km
away. If the Moon’s closest approach to
Earth coincides with a full Moon phase we
have what the media have dubbed a “Super Moon” though it only appears about
10% larger. Were it not for the hype most
people wouldn’t notice any difference in the
Moon’s size.
See “Moon” on page 13
The Reflector
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ESA Pondering Moon’s Back Side
John Crossen
T
the European Space Agency
(esa) has a new President, JohanDietrich Wörner. At the 31st National Space Symposium, Wörner put forth
his vision of a lunar colony on the far side
of our celestial dance partner. Neither the
Moon colony nor having it on the far side of
the Moon is a new idea. But they do make
sense.
Building a radio telescope on the Moon’s
far side would help telescope reception
greatly because it would be free of the
interfering “chatter” it would pick up from
Earth-based sources were it on the Earthfacing side.
So we can score one for the fact that the
Moon doesn’t appear to rotate because it is
gravitationally locked in position by planet
Earth. On the other hand communications
with Earth would have to be beamed from
a satellite orbiting the Moon or an antenna
set up on the near side of dear old Luna.
Those who might think that the far-side
of the Moon is always in darkness are themselves in the dark. At New Moon phase the
far-side of the Moon faces the Sun and is
totally lit. Only when the Moon is in its full
phase — directly opposite the Sun — is the
far-side in total darkness. All of the phases
in between allow the far side different levels
of lighting just as they do the Earth-facing
lunar side.
Wörner sees the lunar colony as a stepping stone from the International Space
Station (iss). The Moon base would be a
learning phase for all the countries involved
before heading on to the colonization and
exploration of Mars.
Key points he mentioned were learning
how to better reuse supplies rather than
relying on shipping new supplies. It works
for the iss, but Mars would be a long haul
and a long wait. Also of importance would
be making use of available on-site materials. On the Moon that could mean building
Lunar Fars Sde. Welcome to the far side of the Moon.
You’ll notice that it is more crater-pocked than the side
facing us. Building a Moon colony here might involve
mining lunar regolith (a sand-like material) that covers
the Moon’s surface. It could be used to mould building
blocks for lunar structures.
structures based on the widely-available
regolith. Then, too, there is the problem of
financing such a monumental adventure.
Again with each nation contributing
from its capabilities such as electronics,
optics, computers etc, no one country has to
shoulder the load be it finances or research.
National Aeronautics and Space Administration (nasa) leader Charles Bolden was
also at the symposium and on the panel
with Wörner. He expressed interest in the
mission saying; “Although Mars is the ultimate destination for humanity, we mustn’t
forget that there are lots of other places in
the solar system. And there are places where
humans will go and must go.” He continued
saying; “A lot of our international partners
are interested in the Moon.”
Currently nasa is interested in establishing an infrastructure orbiting the Moon
that will assist other countries and commercial enterprises in landing on the lunar
surface. The time from 2020 to 2030 will
be spent on this program and he is inviting
other nations to participate.
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continued from previous page 10
Seven Sisters
tion Orion rising just behind them — still in
hot pursuit.
There are probably as many renditions
of the aforementioned story as there are
cultures on the globe. They are visible from
the North Pole to the tip of South Africa.
Once you have them in sight, you may wish
to switch to a pair of 10 × 50 binoculars. The
ladies are dazzling at just 10 power and
binoculars with a 50 mm front lens have
plenty of light gathering ability for doing
astronomy.
The Seven Sisters are only about 1 million years old. In cosmic terms that’s pretty
young. The star cluster is about 425 light
years from Earth. That makes our ladies the
closest star cluster to dear old terra firma.
By the way, a light year is the distance a
beam of light would travel in one year. That
works out to 10 trillion kilometres per light
year.
The Seven Sisters was first catalogued by
Charles Messier. It is the 45th item on his
list of deep sky objects and is often referred
to as Messier 45 or just M45. So get out and
look up. One of astronomy’s most beautiful
sights is waiting for you.
continued from previous page 11
Moon
The Moon also helps stabilize the Earth
as it rotates. Without the Moon’s gentle
gravitational pull on Earth, our home planet
would wobble like a top spinning down. As
a result we’d have dramatic weather swings.
Given that life needs millions of years to
take hold and adapt to a climate, those drastic swings would make it impossible for life
on Earth to begin.
Unfortunately, the Moon is slowly pulling
away from Earth. It’s not much, just 3.8 cm
per year. But it adds up with the time. Since
first taking laser measurements in 2007,
the Moon has drifted 30mm or 1.3 inches
further away every year. Over time that will
13
affect our tides and the gravitational stability of our planet. The difference between
high and low tides will be much less. So our
friends in the tourist business at the Bay
of Fundy had better make money while the
tides are still high and low.
Since the Moon was created by an impacting protoplanet now referred to as
Theia, over 3.5 billion years ago it has
slowly moved away from Earth. Early on
the Moon and Earth were separated by
just 200,000 km. Now we average about
375,000 km separation. What the future
brings as the Moon continues to expand its
orbit could mean a bad sol for Mars.
continued from previous page 7
Space Race
The first woman in space was Valentina Tereshkova. On February 16, 1962 her
Vostok 6 rocket left Earth and she successfully completed 48 orbits of the home
planet. Due to regulations Valentina was
made a honourary member of the Soviet
Air force before she could become a Cosmonaut. 1n 2013 she volunteered to join the
one-way Mars mission to establish a colony
on Mars. She was the first and only female
in the male-dominated Russian space programme.
Let’s jump ahead to July 20, 1969. That’s
when Apollo 11 set down on the Moon. The
u.s. had won the space race by landing the
first humans on the Moon. The late Neil
Armstrong was the first to set foot on dear
old Luna and Buzz Aldrin was right behind.
Astronaut Michael Collins remained aboard
the orbiting command module and would
eventually rendezvous with the moon-walkers for the return to Earth.
The first joint U.S.-Soviet space mission
came about in 1975. It was an open showing
of the new detent between the U.S. and Soviet Union. Dubbed the Apollo-Mir mission
it was the culmination of a team design for
the docking mechanisms that would allow
the last Apollo spacecraft to dock with the
Mir Space Station.
The Reflector
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p eterb o ro u gha s tro no my.co m
The Sky this Month
Mercury is well placed in the early
morning sky from the 7th to the 31st.
Greatest elongation west (18°) on the
16th. Inferior conjunction on the 30th.
Venus reaches greatest elongation
west (46°) on the 26th. In conjunction
with Jupiter on the 26th.
Mars is low in the eastern dawn sky in
Leo for the month. In conjunction with
Jupiter on the 17th.
Jupiter low in the morning sky in Leo.
In conjunction with Mars on the 17th
and Venus on the 26th.
Saturn is low in the southwest twilight evening sky. Moves from Libra to
Scorpius on the 16th.
Orionid Meteor Shower peaks at
7 PM on the 21st.
Zodiacal Light from the 11th for
the next two weeks in the east before
morning twilight.
Moon Phases
Last Quarter
New Moon
First Quarter
Full Moon
5:06 PM October 4
8:06 PM October 12
4:31 PM October 20
8:05 AM October 27
Vo l 1 4 • I s s u e n o. 8 • O c t o b e r 2 0 1 5 •
continued from page 3
Wishes on a Star
The paa was out in force with a couple
of new faces hovering over the eyepiece.
Bridget Gallagher got her new scope up and
running. It was her first outing with the
group and she soon had a long line of eager
stargazers at her scope.
I left before the event was over, but I’d
guess the turnout was at least 150, and
that’s just for the stargazing session which
concluded the evening’s entertainment. It
was a great outing with 10 paa scopes on
hand.
We would like to give special thanks to
the weather folks who arranged a warm,
clear night for us. If you have a scope and
haven’t been out with the observing group
you’re missing out on a lot of fun. You don’t
have to know a lot, just show up and we’ll
show you the wonders of the universe.
continued from page 6
Saturn
a thick layer of clouds, but dig inside and
that’s where the ice is. Its gas that’s so cold
it has frozen. And again both have rocky
cores.
Ever hear someone say you can tell the
difference between a star and a planet because stars twinkle. That’s not always true.
On a night when the Earth’s upper atmosphere is very active even planets appear
to twinkle. It’s the movement of our atmosphere that bounces the starlight around
and makes stars appear to twinkle. Ditto
goes for the planets. So make sure when
you wish upon a star it’s not a planet.
15
continued from page 4
Pluto
that any heat from decay should have dissipated into space millions of years ago.
Or could Pluto be some kind of anomaly?
It’s a riddle waiting to be solved and there’s
still evidence coming in from the New Horizons spacecraft.
Scientists were also expecting to find a
bland little ice ball with a uniform surface.
Instead they found a multi-coloured world
with huge flat plains, mountains of ice and
red dust-like particles that not only covered
large portions of Pluto’s surface, but those
of its largest moon, Charon.
Currently it is thought that the red
particles were formed by a chemical reaction between the methane and nitrogen in
Pluto’s atmosphere. When exposed to the
infrared light wave lengths of sunlight these
two chemicals react. The end result is a red
dust called folin. Speculation is that much
of Pluto’s surface is covered in a thin coating or folin. But the folin isn’t just on Pluto.
Pluto’s atmosphere has been escaping to
the polar region of Charon. Because the two
bodies share the same centre of gravity as
they orbit each other, the folin has drifted
from Pluto to Charon where it has condensed over million of years to form a thin
layer on Charon’s northern polar region.
An even bigger surprise was what scientists didn’t find — fields of crater upon crater overlapping each other. Instead much
of Pluto’s surface is smooth and crater-free.
This doesn’t mean that Pluto escaped being hit by meteors. Instead it suggests that
Pluto has been actively resurfacing itself.
How and why are still up for grabs.
The Reflector
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continued from page 1
Measure the Moon
ing a lunar eclipse, Earth’s shadow is about
3.5 times larger than the Moon, with some
slight variations dependent on the Moon’s
point in its orbit. Simply divide Earth’s radius by your measurement to figure out the
Moon’s radius!
Even with this primitive method, it’s
straightforward to get a measurement for
the moon’s radius that’s accurate to within
15% of the actual value: 1,738 km. Now that
you’ve determined its physical size and its
angular size, geometry alone enables you
to determine how far away it is from Earth.
A lunar eclipse is coming up on September
28th, and this supermoon eclipse will last
for hours. Use the partial phases to measure
the size of and distance to the Moon, and
see how close you can get!
Articles
Submissions for The Reflector must be received
by the date listed below. E-mail submissions
are preferred (Microsoft Word, OpenDoc, ASCII
and most common graphic formats are acceptable). If your article contains photso or graphics,
please provide a separate file for each. Typed or
hand-written submissions are acceptable provided they are legible (and not too long.) Copyrighted materials will not be published without
written permission from the copyright holder.
Submissions may be edited for grammar, brevity, or clarity. Submissions will be published at
the editor’s sole discretion. Depending on the
volume of submissions, some articles may be
published at a later date. Please submit any articles, thoughts, or ideas to:
[email protected]
Next submission deadline:
October 27 2015
Meetings
The Peterborough Astronomical Association meets every first
Friday of each month, except July and August, at the Peterborough Zoo Guest Services and Rotary Education Centre (inside the main entrance at the north end of
the Zoo) at 7 p.m. P.A.A. general annoucements will begin each
meeting with the guest speaker starting at 7:30 p.m.