Transcript Astronomy Merit Badge God is infinite, so His universe must be too.

Astronomy Merit Badge
God is infinite, so His universe must be too. Thus is the
excellence of God magnified and the greatness of His
kingdom made manifest; He is glorified not in one, but in
countless suns; not in a single earth, a single world, but in
a thousand thousand, I say in an infinity of worlds.
- Giordana Bruno, 1584, "On the Infinite Universe and
Worlds"
The word Astronomy means
“naming the heavens”
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Why should we care
about Astronomy?
Why should we care about
Astronomy?
Objects in the sky seem remote but there are
many reasons we should pay attention to them
Why should we care about astronomy ?
Timekeeping
In the past:
•Before watches and written calendars people could tell the time of day
and the date from the sky. This was particularly important for farmers in
determining when to plant their crops, to know when the spring rains
were coming or when winter would soon be setting in.
•Stonehenge, pyramids, etc. all have architectural elements that were
used for timekeeping
•There were pocket sundials made in 1600s which would allow you to
tell the time, even at night, using the stars, within 15 minutes of
accuracy.
Modern day:
If you know your constellations and you know the time of year, you can
determine the approximate time by looking at the night sky.
Why should we care about astronomy ?
Navigation
In the past: Before compasses and GPS, travelers
used the stars to tell direction, especially sailors
(using a sextant).
Modern day: Compasses break, GPS batteries lose
power, GPS units can’t find satellites, or are simply
inaccurate. Stars are always there and with stars
and a map you can find your way even in the dark
Why should we care about astronomy ?
Predicting the future
In the past:
The earliest astronomers (Sumerians, Egyptians, Chinese) watched
the skies for scientific reasons but also to try and predict events on
earth (birth and death of kings, outcomes of battles, etc.). The only
known record of this actually working was the Star of Bethlehem. The
three wise men were amateur astronomers.
Astrology is bunk. The only effect the heavens have on our daily lives
is providing light and heat and the occasional news story about a
close brush with a space object.
Modern day:
Modern astronomers survey the sky for local threats to the Earth such
as asteroids and comets with orbits close to us (NEOs – Near Earth
Objects), dangerous solar activity (flares), and local supernovae (a
star blowing up close to us (within 100 light years) could cause us a
lot of trouble)
Why should we care about astronomy ?
Scientific advancement
In the past: Studying the stars helped people learn to
practice agriculture, predict seasonal floods, understand
the shape of the Earth.
Modern day:
Understanding the chemical and physical processes in
the stars and other celestial objects can help us
understand how things work on Earth.
Mapping the universe can help us understand what it
looks like and appreciate God’s engineering skill.
Why should we care about astronomy ?
There are extremely cool things out there to look at and study
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Manmade: Satellites, ISS
Meteorites and fireballs (these last 4-5 seconds)
Aurorae (if conditions are right)
Details of lunar craters
Other planets
Moons of other planets
Asteroids and comets
Asteroids with moons (Eris, etc. – get from Celestia presentation)
Differently colored stars (you can actually see the colors)
Double stars
Nebulae (Ring nebula, Orion nebula)
Globular clusters
Galaxies by themselves and galaxies that are in the process of colliding with
each other
Exploding stars (supernovae – 1987A)
Black holes, white holes, wormholes
Extrasolar planets (with professional equipment)
Views of galactic clusters taken by Hubble telescope in areas of space thought to
be blank!
See back in time to the beginnings of the universe (speed of light)
Maybe alien life forms????
And lots more!!
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Observing Safety
Observing Safety – Weather Safety
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Weather Safety – exercise the same weather precautions as on a campout or hike.
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When observing, you will be outdoors for long periods of time without moving very much.
You can get frostbite just as easily in your backyard as you can on the Arctic tundra. You can
get heat exhaustion even at night if it’s hot enough outside. Dress appropriately and take the
appropriate precautions for cold or hot weather.
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Heat Exhaustion
– Signs – elevated body temp, skin pale and clammy, heavy sweating, nausea, dizziness, fainting,
pronounced weakness and tiredness, headache, muscle cramps.
– Treatment – have victim lie down in a cool spot with feet raised. Apply cool damp cloths to skin. Give
them water
Heatstroke
– Signs – red, hot dry skin, no sweating, extremely rapid pulse, confusion or disorientation, fainting or
unconsciousness, convulsions
– Treatment – place victim in a cool spot with head and shoulders raised, remove outer clothing, sponge
bare skin with cool water, apply cold packs, use fan or place victim in tub of cool water. Obtain medical
help immediately.
Hypothermia – when body’s core temperature drops so low it can no longer keep warm.. Can occur even in mild
weather. Cool and windy conditions are particularly dangerous.
– Prevention – keep warm and stay dry. Eat plenty of energy foods (nuts, dried fruit, peanut butter)
– Signs – Victim may begin shivering, then stop as they get colder. Irritability, sleepiness, incoherence,
disorientation, inability to think clearly.
– Treatment – move victim to warm shelter, remove damp clothing, warm person with blankets, cover
head with warm hat or covering, offer hot drinks. Severe hypothermia requires immediate medical
attention.
Dehydration –Can happen even in cold weather. Stay hydrated
If you or someone observing with you begins to have trouble with the weather, remember
your first aid and use the same treatments you would use for hypothermia, heat exhaustion,
etc. as you would on a scout campout.
Prepare for bugs (both the biting, stinging kind and the kind that will crawl up your leg
and imbed themselves in you) with bug spray, long pants and shirts. Mosquitoes are
just as active at night as during the day.
Observing Safety - Location
• Most of us can’t see in the dark and when we’re
observing, we don’t want to ruin our night vision.
This can lead to problems if there are hazards in
the area where we’ll be observing
• Check the observing area during the daytime for
holes, dropoffs, pipes sticking out of the ground,
etc. Make note of them so that you won’t find
them accidentally in the dark.
Observing Safety – Don’ts
• Observing the sun - You don’t look at the sun through a
telescope for two primary reasons
– Blindness - It will permanently blind you by burning your retina.
The lenses in a telescope are specifically designed to focus light
to a small point. The rays of the sun are very powerful and when
focused to a point, can create tremendous heat in a small
amount of time. Anyone who has lit paper on fire with a
magnifying glass knows how this works.
– Telescope Damage - The inside of the telescope is sealed and
cannot vent heat. If the inside gets too hot, the lenses can be
damaged. The adhesive that secures the lens pieces together
can melt and ruin the view. There are special filters that can be
used with a telescope for solar viewing, but it is not advisable for
an amateur to attempt to do this. Plus, they’re really expensive.
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Astronomy Definitions
Astronomy Definitions
Star – a hot glowing ball of gas that produces energy by nuclear
reactions in its core.
Planet – large, non-luminescent, sperical body that orbits a star
Rotate – spin around an axis.
Revolve – go around another object (orbit)
Meteor terminology
Meteoroid - small rock that orbits the sun. It’s a meteoroid while
it’s in space
Meteor – rock from space that hits the earth’s atmosphere and
flashes (shooting start, meteor shower)
Meteorite - rock from space that hits the ground and remains
intact.
Moon – small body that orbits a planet.
Asteroid – Large rocky body in space that orbits the sun. In our
solar system, we have a large number of these in the Asteroid belt
Comet – Icy object from outer solar system. When it comes close to
the sun it grows a tail of steamed off ice.
Solar System – Collection of planets, moons, comets, asteroids, etc.
that orbit a star
Astronomy Definitions
Constellation - a pattern of stars in the sky. Early astronomers
(Ancient Greeks, Sumerians, Egyptians, etc.) drew imaginary
lines between stars to form images of mythological characters
or familiar creatures. There are 88 recognized constellations.
Asterism – a portion of a constellation
Star Cluster – small group of stars within a galaxy
Galaxy – A system of millions or billions of stars, together with
gas and dust, held together by gravitational attraction
Milky Way – Not just a chocolate bar - Our own galaxy
Red Giant – Old star that has bloated up several thousand times
its original size
White Dwarf – The remnant of a relatively small star that isn’t big
enough to go supernova. Very dense
Neutron Star- The highly dense core of a star left over after a
supernova, but not dense enough to form a black hole.
Black Hole – Very massive star that has gone supernova and
then collapsed back in on itself and become so dense that
even light can’t escape.
Universe – Everything that exists
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All about the Moon
Where did the moon come from?
• It is believed that our moon resulted from a collision
with another body (about ½- ¾ the size of Earth) that
combined the two large bodies and kicked off a bunch
of molten rock that formed the moon. So the impetus
for the moon’s current orbit came from that original
collision.
• The orbit of the moon around our planet is elliptical
(not a perfect circle) so the distance between Earth
and moon can vary.
• Apogee – when the moon is farthest away from Earth
• Perigee – when the moon is at its closest to the earth
The Moon – Orbit
How does the Moon stay in orbit?
What is an Orbit?
An orbit is falling without hitting the ground
• Place a cannon on a mountain
• When the cannon fires, the cannonball
will follow its “ballistic trajectory” and hit
the ground
• Use more gunpowder and the cannonball will fly
further before it hits the ground
• If you use enough gunpowder, the cannonball will fly
so far that it NEVER hits the ground. The earth curves
away at the same rate that the cannonball drops.
The cannonball is in orbit!
•The moon orbits the Earth because it’s going fast
enough that it falls continuously without hitting the ground.
The Moon – Lunar Features
Close Up of Lunar Features with Labels
Naked-eye View
(What you see in the
sky)
The Moon – Phases
• Phases of moon:
– New moon (moon is between Earth and the sun)
– Crescent (waxing when growing, waning when
getting smaller)
– First quarter – half of the moon is illuminated.
It’s called first quarter rather than half moon
because the moon is ¼ through it’s entire cycle
at this point.
– Full Moon (Earth is between moon and the sun)
– Gibbous – greater than quarter moon (more
than half illuminated) (waxing and waning)
Lunar Phases
• Moon takes 28 days to orbit the
Earth and 28 days to rotate once on
its axis so the same side always
faces the earth. The Far Side of the
moon was never seen until space
probes took photos in the 1960s
• Moon moves slowly eastward
over successive nights. As it does
so, it becomes increasingly
illuminated by the sun until it is
completely illuminated at the full
moon.
• At full moon, it is completely
opposite the sun in the night sky.
• Note that the moon also moves
higher and lower in the sky through
each cycle. This is why it’s possible
for the moon to eclipse the sun (or
the Earth to eclipse the moon) on
occasion, but it doesn’t happen
every month.
Lunar Phases – more detail
The outer ring
of moon
images shows
how the moon
is seen from
Earth. The
inner ring of
moon images
shows the
moon’s
orientation to
Earth and sun
The Moon – Total Solar Eclipse
Total solar eclipse – when the moon gets between the
sun and the earth and completely blocks the light. This
only happens in a small path along the earth’s surface,
not the whole planet. The moon is too small and too far
away to completely block all light to the earth.
The Moon – Total Solar Eclipse
• The last total solar eclipse visible from the
continental U.S.A. occurred on Feb. 26,
1979 (your merit badge counselor
remembers this one).
• The next two total solar eclipses visible
from the U.S.A. occur on Aug. 21,
2017 and Apr. 8, 2024.
The Moon – Partial solar eclipse
Partial solar eclipse – (also called an “annular” eclipse) occurs
when the moon is farther from the earth (lunar apogee) and closer
to the sun. The moon’s shadow does not completely cover the
sun (see picture below for annular eclipse).
The Moon –
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The Planets
The Planets
• What are the 5 most visible planets?
– Mercury
– Venus
– Mars
– Jupiter
– Saturn
The Planets
• The other planets (Neptune, Uranus,
Pluto) are so far away that they are not
visible to the naked eye. They weren’t
even discovered until the last couple of
centuries (Uranus 1780, Neptune 1846,
Pluto 1930).
The Planets
Inferior vs. Superior planets
What is an inferior planet?
• Any planet between us and the sun
What is a superior planet?
• Any planet beyond Earth’s orbit
Name the inferior planets:
• Mercury
• Venus
Name the superior planets:
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Mars
Jupiter
Saturn
Uranus
Neptune
Pluto (unofficially)
The Planets
Inferior vs. Superior planets
Other than their position relative to Earth, what is the
difference between Inferior and Superior planets?
Because Inferior planets are closer to the sun than we
are, they can get between us and the sun and we can
see their “darkside”. This means that the Inferior
planets can have phases, much like our moon.
Since Superior planets are farther away from the sun
than we are, we can never see their darksides
(because the dark side is always facing away from
us). As a result, we never see phases on Superior
planets.
The Planets
Phases of Venus
This is a photo collage of the planet Venus as it
travels from our side of the sun to the far side. Note
that the planet shows phases similar to our moon.
The crescents at top are very large because Venus was
closer to us at that point. The full disks at bottom are
smaller as Venus gets farther away but more
sun can shine on them so we see a disk.
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The Sun
Layers of the sun
Core – center – where
reactions take place
Radiative zone – where
energy leaves the core
Convective zone –
where energy is carried
by rising and falling
currents of hot gas
called convective cells.
Photosphere – outer
surface
Chromosphere – in
violent motion, reddish
rim during solar
eclipses.
Corona (crown) –
extends outward from
the sun in the form of
the solar wind.
The Sun
Corona
Chromosphere
Photosphere
Convective Zone
Radiative Zone
Core
What are Sunspots?
• Sunspots are temporary phenomena on the
photosphere of the Sun that appear as dark
spots. These spots are cooler than the
surrounding area, but only by comparison
(4500K vs. 5800K).
• They are caused by intense magnetic activity,
which prevents the hotter gases from welling
up from underneath.
• Some sunspots are so large they can be
viewed from Earth without a telescope (e.g.
using a pinhole camera). The Chinese were
studying them thousands of years ago, long
before telescopes were invented.
Sunspot Cycles
• Sunspot appearances fluctuate over a regular 11 year
cycle. Sunspot activity can vary over long periods of
time (i.e. there were more sunspots on avg from
1900-1960 and fewer from 1960-present).
• Sunspots were rarely observed during the Maunder
Minimum (1645-1715) which coincided with a cooling
period called the Little Ice Age. This may suggest that
sunspots actually indicate an increase in solar output
and can directly affect our weather.
• Sunspots (called starspots) have even been observed
on other stars
Sunspots-Effects on Earth
• Studies of rock strata (layers) have
suggested that the solar cycles have been
active for hundreds of millions of years, if
not longer; precambrian sedimentary rock
has revealed changes in layer thickness,
with a pattern approximately repeating every
eleven layers.
• Analysis of tree rings has revealed a
detailed picture of past solar sunspot cycles
for the last 11,400 years
• Sunspot activity affects weather and plant
growth
Why do sunspots last so long?
• Recent observations from the Solar and
Heliospheric Observatory (SOHO) using sound
waves traveling below the Sun's photosphere
have been used to study the internal structure
of sunspots. This analysis shows that sunspots
behave like terrestrial hurricanes. This
explains why they don’t just appear and
disappear, but instead, last for weeks at a time.
Solar Flares – What are they?
• A solar flare is a brief eruption of intense highenergy radiation from the sun's surface. This
explosion is accompanied by a burst of
charged particles.
• Flares occur in active regions around sunspots
• Flares are powered by the sudden release of
magnetic energy stored in the corona.
• The background picture shows a solar flare (on
left) and the resulting prominence (on right)
Solar Flares
• The first solar flare observed by humans was
seen in September of 1859 by astronomers
who were observing sunspots. It was so big
that it was visible to the naked eye and is
considered one of the most powerful on record.
• The flare interrupted electrical telegraph
service and caused visible aurorae as far south
as Havana, Cuba.
• The background picture shows a massive flare
eruption (on right) in filtered light.
Solar Flares
• In June of 2011, scientists witnessed the most
powerful solar eruption ever seen. A very large
amount of material lofted up, expanded, and fell
back down over half the surface area of the sun
(as seen in the background picture on this slide).
• When flares occur, they simultaneously launch a
large quantity of particles through the solar corona
and into space. This is called a coronal mass
ejection (CME). It takes 1-2 days for this to reach
Earth.
• If one of these powerful flares—and its coronal
mass ejection—were to face Earth, the particles
would pound satellite components with charged
particles, short some out, and potentially cripple
them. The particles can also effect telephone and
electrical lines.
Earth’s Axial Tilt
• Because of the axial tilt of the Earth, the
amount of sunlight reaching any given point on
the surface varies over the course of the year.
This results in seasonal change in climate.
• Ironically, in the summertime in the Northern
hemisphere, the sun is farthest away from us..
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Stars and
Constellations
The Zodiac Constellations
• What’s special about Zodiac constellations?
They are centered on the plane of the ecliptic which is
the path that the sun, moon, and planets appear to
follow in the sky. This is basically the plane of the solar
system. These constellations have been misused by
astrologers to foretell the future and classify people’s
personalities based on their birth date. It doesn’t work.
Astrology is bunk.
• Trivial note: If you know your Zodiac sign, that is
the constellation that the sun is in during your
birth month. At least, that was the case about
2500 years ago. Since then, things have shifted
around a bit and the sun is now about 1
constellation off from that. Further proof that
astrology is bunk because your Zodiac sign is
actually one off from what you think it is.
The Zodiac Constellations
Zodiac Constellations and the
Plane of the Ecliptic
Diagram of the Sun’s path through the plane of the ecliptic
Zodiac Constellations
• Spring: Gemini, Cancer, Leo, Virgo, Libra
• Summer: Libra (scales), Scorpius, Sagittarius,
Capricornus, Aquarius
• Fall: Capricornus, Aquarius, Pisces, Taurus,
Gemini, Aries
• Winter: Gemini, Taurus, Pisces, Aquarius
Let’s take a closeup look at a some of these Zodiac
constellations. On the next few slides, you’ll see the
outline of a constellation. Click on that and you’ll
see a picture that shows you what the ancient
astronomers saw in that constellation.
Leo the Lion (Spring)
Libra:
The Scales
(Summer)
Scorpius:
The Scorpion
(Summer)
Taurus (the Bull)
(Fall/Winter)
Gemini:
The Twins
(Winter)
Non-Zodiac Constellations
• Spring: Big Dipper, Little Dipper, Cassiopeia,
Cepheus, Draco, Corona Borealis, Bootes,
Hercules, Auriga, Perseus, Coma Berenices
• Summer: Big Dipper, Little Dipper, Cassiopeia,
Bootes, Lyra, Cygnus, Aquila, Hercules
• Fall: Big Dipper, Little Dipper, Cassiopeia,
Pegasus, Andromeda, Perseus, Pleiades
• Winter: Orion
Corona Borealis – Northern Crown
(Spring)
Cepheus - the King
(Spring Constellation)
Cassiopeia’s Husband
Looks like a house
Bootes – the Shepherd
(Summer Constellation)
Chases the Big Bear around
the North Star
Looks like a broken kite
Cygnus – the Swan
(Summer Constellation)
Also known as the Northern Cross
Pegasus-the flying horse
(Fall Constellation)
Orion the Hunter
(Winter)
Non-Zodiac Constellations
Year Round Constellations
While most constellations are only visible to us
for part of the year, the following constellations
are visible all year because they are positioned
close to the polar axis (around Polaris):
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Ursa Major (Big Dipper)
Ursa Minor (Little Dipper)
Cassiopeia (The Queen)
Draco (The Dragon)
Year Round Non-Zodiac Constellations
Big Dipper/Ursa Major/Big Bear
Year Round Non-Zodiac Constellations
Little Dipper/Ursa Minor/Little Bear
Year Round Non-Zodiac Constellations
Cassiopeia – The Queen
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Finding the North Star
Finding the North Star
• Find Right pan of dipper
Finding the North Star
• Draw line to closest bright star
Finding the North Star
• Find open W of Cassiopeia
Draw line to brightest star
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Spring and Summer
Triangles
Knowing how to identify the Spring and
Summer Triangles can help you find your
way around in the night sky
Spring Triangle
Composed of the
brightest stars in 3
constellations:
• Arcturus (Bootes)
• Denebola (Leo)
• Spica (Virgo)
Summer Triangle
Composed of the brightest stars in 3
constellations:
• Deneb (Cygnus)
• Vega (Lyra)
• Altair (Aquila)
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All About Stars
Star Brightness
– A stars apparent magnitude (how bright it looks
to us on Earth) does not necessarily indicate it’s
actual brightness. A fairly dim star may seem
very bright to us if it’s very close to us
(dependent on proximity). Sirius looks very
bright to us, but it’s only 9 ly away. Rigel is
much brighter, but it’s 800 ly away.
– Big stars are not necessarily brighter than
smaller stars. Hot stars are not necessarily
brighter than cooler stars.
Stars and heat
Stars in order of heat:
• Blue – hottest (Rigel in Orion)
• White – Canis Major
• Yellow – our own sun (Sol)
• Orange - Arcturus
• Red – coolest – Betelgeuse in
Sagittarius
Magnitude
• Star Magnitude is the measure of how
luminous (bright) a star is.
• There are two different kinds of magnitude:
– Apparent Magnitude
– Absolute Magnitude
• Apparent Magnitude="The brightness of a star
or other celestial body as viewed by the unaided
eye.“
• Absolute Magnitude= " The magnitude of a star
as it would appear to a hypothetical observer at
a distance of 32.6 light years."
Magnitude – Brightness Scale
Negative numbers indicate greater brightness
1st Magnitude Stars
These stars are visible in constellations you know:
• Arcuturus (Bootes – base of kite)
• Spica (Virgo)
• Vega (Lyra – star that joins parallelogram and
triangle)
• Altair (Aquila)
• Antares (Scorpius)
• Capella (Auriga)
• Betelgeuse (Orion)
• Rigel (Orion)
• Sirius (Canis Major)
• Aldebaraan (Taurus)
Stars Dimmer than 1st Magnitude
• Deneb (Cygnus – tail of the swan)
• Polaris (North star in Little Dipper)
• Castor and Pollux (Gemini – Pollux is
brighter twin, stars make up their heads)
• Mizar and Alcor (visual binary in handle of
Dipper – 2nd star from the end of the
handle)
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What reduces the
magnitude of Stars?
Light Pollution
• What is it?
– Too much artificial light which dims the night sky.
• How to combat it
– Cover your head down to your shoulders with a dark cloth so that
stray light doesn’t interfere with your vision
– Observe later at night as businesses close down and people go to
sleep
– Look for bright objects – Sirius, Vega, Spica, Aldebaraan, Arcturus,
etc.
– Head away from the cities. Even just a few miles into the country
can make a huge difference.
• Turbulent air can also affect viewing.
(Think of shimmery hot air over a road or sidewalk in summer)
– Look for:
• No wind
• Cooler nights
• Lower humidity
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Galaxies
Galaxies
Galaxy – Very large groups of stars with great
distances between them.
Milky Way - Milky river of dust that can be seen
under very dark skies in the summer. It runs
directly overhead in July. It is made up of stars
and lots, and lots of stardust. So much stardust
that we can’t see the center of our galaxy.
Which might be a good thing for us if the center
of the galaxy really is a super black hole like
scientists believe. Radiation from that black hole
would be deadly, even at this distance.
Our Galaxy – The Milky Way
Our galaxy is
considered a barred
spiral. Each arm of
the galaxy is named
after the
constellation in
which it can be seen
in our sky. The arm
in which our sun is
located is marked on
the diagram.
Our Galaxy – Overhead View
Andromeda Galaxy (M31) - spiral
Our closest
galactic neighbor
The Andromeda
Galaxy is the
closest galaxy to
us in the universe.
It’s so close, that it
is the only galaxy
that is actually
visible with the
naked eye (if you
know where to
look).
Andromeda is a
very large galaxy,
possibly 1.5-2
times as big as
our own Milky
Way.
Andromeda is a
spiral galaxy.
Sombrero Galaxy (M104) – lenticular: A
galaxy having a central bulge surrounded by a
flattened disk with no pattern of spiral arms.
Whirlpool Galaxy (M51) - spiral
Here’s a view
of a spiral
galaxy from
above. This
galaxy has a
companion
(bright object
at far right).
Feeling Small
6
5
4
3
1
2
The Nearest
Superclusters
Beyond the local
supercluster is a large
collection of other
superclusters stretching
all across the visible
univers. This graphic is a
map of the universe
within 500 million light
years. It shows most of
the major galaxy
superclusters that
surround the Virgo
supercluster. These
superclusters are not
isolated in space but
together with many other
smaller concentrations of
galaxies they form parts
of extensive walls of
galaxies surrounding
large voids. Three of the
biggest walls near us are
marked on the map as
well as several of the
largest voids. There are
several hundred
thousand large galaxies
within 500 million light
years, so even on this
scale our galaxy is a very
insignificant object.
Hubble Deep Field
In December 1995, the Hubble Space Telescope was
pointed at a blank area of the sky in Ursa Major for ten days.
It produced one of the most famous astronomy pictures of
modern times. Almost every object in this image is a galaxy
typically lying 5 to 10 billion light years away.
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Tools of the Trade
Why are telescopes and other
astronomical tools important?
• Because they significantly increase the amount of light that our
eyes can gather and more light means that more detail is visible
to us (use example of standing far away from a TV set and how
the picture gets clearer the closer you get (or the bigger it is)).
• This even holds true for instruments that detect radiation in
non-visible wavelengths such as infrared, ultraviolet (show
rainbow to explain this), radio waves, gamma rays, x-rays, etc.
We can’t see any of these things with our naked eyes, but
these instruments can see them and allow us to see them.
• This is important because all of these sources of
electromagnetic radiation provide us a ton of information about
the astrophysical objects out in space. We’re trapped in a very
small area in the universe (at least on a cosmological scale –
even our farthest probe hasn’t left our solar system yet), yet
because we have these tools, we know a lot of information
about objects and phenomena that are very far away and
existed a very long time ago.
Binoculars
• Allow “binocular vision” which provides depth of
field. This is particularly important for comet
hunting, lunar observing, Milky Way, star
clusters.
• Light travels through the
large objective lens
then through the
porro prism lenses
and then through
the eyepiece
lenses.
Big Binoculars
• These are 25x100
binoculars (25x
magnification at eyepieces,
100mm objective lenses at
the ends of the barrels).
These are much bigger
than the 7x35s and 10x50s
that you usually buy in the
store.
Bigger Binoculars
Some binoculars can be very large, basically
two refractors next to each other on a tripod
or mount.
How to Care for Binoculars
Lens Care
• Always replace the lens caps on both the objective
and eyepiece lenses when finished. This will keep
dust and scratches off of the lenses.
• Always store binoculars in their case in a cool, dry
location. Attics are not a good place to store any
optical device. Heat can destroy lenses.
• Only clean binocular eyepieces and objectives
when absolutely necessary and only with microfiber
cloths (e.g. eyeglass cleaning cloth).
Types of Telescopes
Three main types of visible light scopes:
• Refracting (lenses)
• Reflecting (mirrors)
• Catadioptric (multiple mirrors)
Telescopes - Refractors
Refractor
• Uses lenses to gather
and focus light
• Same type as original
Galileo telescope
Telescopes - Refractors
Telescopes-Early Use
What Galileo saw with his refractor:
Saturn has been known since prehistoric times because it is easily visible to the
naked eye. Not until the invention of the telescope, however, did people observe
Saturn's magnificent rings.
Galileo Galilei was the first to observe Saturn with a telescope in 1610. Because of
the crudeness of his telescope, he couldn't determine what the rings were. He
incorrectly guessed that there were two large moons on either side of Saturn. Two
years later when he viewed Saturn again, the "moons" had disappeared. We know
now this is because Galileo was viewing the rings edge-on so that they were
invisible. After another two years, Galileo viewed Saturn again and found that the
"moons" had returned. He concluded that the rings were "arms" of some sort.
What Galileo saw
What Galileo drew
Galileo
Telescopes - Reflectors
Reflector
• Uses a mirror to gather
and focus light
• Also called Newtonian
after inventor Isaac Newton
• Modern Newtonians work
much like Isaac’s original
(replica at right)
Telescopes - Reflectors
Reflector
• Parabolic primary mirror gathers and reflects light to
secondary mirror
(diagonal)
Secondary
mirror
reflects
light into
focuser and
through
eyepiece
into eye
Telescopes - Catadioptric
Catadioptric (or compound)
• Uses mirrors and lenses
to gather and focus light
• Lots of power in a compact
form factor
• You pay a lot for that power.
Much more expensive than
refractors and reflectors
• Most common types are:
– Schmidt-Cassegrain
– Maksutov-Cassegrain
Telescopes - Catadioptric
Catadioptric (or compound)
• Parabolic primary mirror gathers and reflects light to
large secondary
mirror
Secondary
mirror
reflects
light into
focuser and
through
eyepiece
into eye
How to Care for Optical Telescopes
• Always replace the lens caps on both the
objective and eyepiece lenses when finished.
This will keep dust and scratches off of the
lenses.
• Always store telescopes in a cool, dry location.
Attics are not a good place to store any optical
device. Heat can destroy lenses.
• Only clean telescope eyepieces and objectives
when absolutely necessary and only with
microfiber cloths (e.g. eyeglass cleaning cloth).
How to Care for Optical Telescopes
• Cover the telescope when not in use.
• Store extra eyepieces and lenses in sealed
plastic bags or food containers to protect from
dust
• Avoid touching the lens or mirrors with your
fingers at all times. The dirt and oils from your
skin can damage them.
Telescopes - Radio
• Radio Telescopes
– Pick up radio waves emitted by objects in
space (planets, stars, galaxies, etc.)
– Reveal temp and composition of objects in
space
Telescopes - Radio
• Radio telescopes can be very large
The Arecibo telescope (shown on this page)
is built into a crater and is 1000 feet wide
• See the inset picture in the lower left of this
slide for an aerial view of the telescope.
Telescopes – X-Ray
X-Ray Telescopes
• Good for finding hot spots in galaxies
• Cosmic x-rays (emitted from very hot objects) can be
used to study dying stars, colliding galaxies, and
quasars (extremely bright starlike objects that give
off enormous amounts of energy)
• Captures X-rays from the edge of the observable
universe
• Orbital X-ray scopes capture rays that are normally
absorbed by Earth’s atmosphere (Chandra?)
Space Probes
• Helios- Sun-scope that tracks solar
flares, sunspots, radiation from near
the sun
• Mercury Probe
• Mars Probes
• Cassini
(Saturn)
Special tools
• Spectroscope – shows spectrum of starlight – what it’s
burning (chemical composition)
– Frauhofer lines, etc.
• Filar micrometer – used for gauging distance between
double-stars.
• Photometer – measures magnitude of stars
• CCD – much like consumer digital devices. First digital
cameras were used for astrophotography back in the 80’s
and earlier. More sensitive than standard consumer
models.
– Astrophotography – basic example – set digital camera for timed
photo (longest time), set light sensitivity to highest level, set photo
mode to B/W, set on tripod facing North star and get a photo of
star tracks (show example).
• Night vision instruments – can capture 2-3 times more
light than your scope alone.
Astronomy Merit Badge
Careers in Astronomy
Careers in Astronomy
What astronomers do
• Design and carry out observing
programs with a telescope or
spacecraft
• Don’t spend all of their time looking
through telescopes. They spend a lot
more time analyzing data from
telescopes and spacecraft
Careers in Astronomy
• To be an astronomer you must be:
– Observant
– Logical
– Imaginative
– Intutive
– Curious
Careers in Astronomy
Astronomers:
• Are typically good at math and science, skilled with
computers
• Need to take calculus, physics, chemistry in school.
• Reading, writing and speaking skills are important
• Are usually found teaching at colleges and
universities
• Usually do research in a particular area of
astronomy
– Planetary science
– Solar astronomy
– Stars and galaxies
• Some have careers in government, others in
aerospace industry
Careers in Astronomy
• Other careers
–
–
–
–
–
–
Science teacher
Science writer
Planetarium or science museum directors and staff
Observing techs or assistants
Telescope operators
Optical engineers
• Related careers
– Computing
– Image processing
– Instrument design and building (for telescopes or
spacecraft)
Amateur Astronomy
What can Amateur Astronomers do?
• Astronomy is one of the few scientific disciplines
where amateurs can make a big contribution. An
amateur with a $150 telescope and a star map can
find a sky object that nobody else has ever seen.
– NEO finding and tracking (most of this is done by amateurs)
– Comet hunting (mostly done by amateurs)
– Spending time looking at things that professionals can’t
spend time on.
• Amateur was able to photograph energy jets radiating from a
black hole and helped solve a mystery about the effect of those
jets on the surrounding nebula
– Galaxy Zoo – classifying galaxies that have been found by
the Hubble deep sky project. Too many for scientists to
classify. You can help classify them with your smartphone
or computer.
– Map storms on Mars and Jupiter
– Get to look at actual stars (Most professionals don’t)
– Still contribute to the field while pursuing other professions
Astronomy Merit Badge
Observation
Requirements
Observation Requirements
In order to really understand astronomy (and complete this badge),
you’ll have to do some of the same things that professional
astronomers do - You’ll watch the sky and record what you see.
1) In order to do that, you’ll have to know when the things you want
to look at in the sky are visible, so you’ll make a planet chart for
2012.
2)Then you’ll track a planet over the course of several weeks,
sketching it’s position so you can see how it moves through the
sky.
3)You’ll sketch the position of the Big Dipper over the course of
several hours so you can observe the visible rotation of the earth.
4)And you’ll sketch the moon’s phases and note some of its
landmarks. You won’t believe how much you can see once you
know what you’re looking at.
You don’t have to be a great artist to do these things, just sketch
what you see to the best of your ability, with special attention to
location and position of objects in the sky.
Observation Requirements
4c) Make two sketches of the Big Dipper.
In one sketch, show the Big Dipper’s
orientation in the early evening sky. In
another sketch, show its position
several hours later. In both sketches,
show the North Star and the horizon.
Record the date and time each sketch
was made.
Observation Requirements
5b) Find out when each of the five most
visible planets that you identified in
requirement 5a will be observable in
the evening sky during the next 12
months, then compile this information
in the form of a chart or table. Update
your chart monthly to show whether
each planet will be visible during the
early morning or in the evening sky.
Planet Chart-2012
Use the planet chart at right
to find the times when
planets are visible in the
night sky for 2012. You can
determine this by looking for
the straight lines that refer to
planets transiting (e.g. “Mars
transits”, “Neptune transits”,
etc.). These lines indicate
when a planet is most visible
in the night sky for the
Northern Hemisphere.
Create a table that lists the
planets and what months
they will be visible in the
night sky. Or . . .
Planet Chart - 2012
You can also visit the following website to
find when planets are visible throughout
2012 and make your chart from this
information:
http://www.telescope.com/Articles/CurrentArticles/Astronomy/Notable-2012-CelestialEvents/pc/9/c/192/sc/199/p/101857.uts?utm_sour
ce=120103&utm_medium=email&utm_campaign
=CelestialEvents
Observation Requirements
6) At approximately weekly intervals, sketch
the position of Venus, Mars or Jupiter in
relation to the stars. Do this for at least four
weeks and at the same time of night. On
your sketch, record the date and time next to
the planet’s position. Use your sketch to
explain how planets move.
See the sample sketches on the next slide for
an example.
Sketch a Planet’s movement
Week #1
Week #2
Week #3
Week #4
Observation Requirements
7) Do the following:
a) Sketch the face of the moon and indicate at least
five seas and five craters. Label these landmarks.
Note: Review the moon information in this presentation
as it lists the most visible craters and seas.
b) Sketch the phase and the daily position of the Moon
at the same hour and place, for a week. Include
landmarks on the horizon such as hills, trees, and
buildings. Explain the changes you observe.