Transcript June 2008 - Otterbein

Welcome to
Starry Monday at Otterbein
Astronomy Lecture Series
-every first Monday of the monthJune 2, 2008
Dr. Uwe Trittmann
Today’s Topics
• Amateur Astronomy – Inspiration by
Observation
• The Night Sky in June
On the Web
• To learn more about astronomy and physics at
Otterbein, please visit
– http://www.otterbein.edu/dept/PHYS/weitkamp.a
sp (Observatory)
– http://www.otterbein.edu/dept/PHYS/ (Physics
Dept.)
Amateur Astronomy - What’s in it
for me?
• That depends on you!
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Motivation
Interests
Patience
Equipment
Position
…
Personally …
• Observing the nightsky inspires me!
– The clearness &he purely colored, tiny spots of light
– Looking into infinity…
• Even more intriguing if you can make sense of all
that changing glitter
• Like traveling to a different country and wanting
to learn more about it
“Two things fill the mind with ever new and increasing
admiration and reverence, the more frequently and
enduringly the reasoning mind is occupied with them:
the star spangled sky over me and the moral law in
me.” (I. Kant)
What’s in the Night Sky?
• Constellations: groups of stars, named for apparent
vicinity “in” the sky (“on” the celestial sphere)
• Moon: watch the phases of the moon change and its
craters, highlands and “oceans”
• Planets:
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Saturn’s rings
Jupiter’s cloud bands and Galilean moons
Venus’ phases
Mars’s polar caps
• Deep Sky Objects: Galaxies, clusters, nebulae
Basic Observations in Astronomy
• Positions of objects (sun, moon, planets, stars …)
• Motion of objects
– with respect to you, the observer
- with respect to other objects in the sky
• Changes (day/night, seasons, etc.)
• Appearance of objects (phases of the moon, etc.)
• Special events (eclipses, transitions, etc.)
 All “in the sky”, i.e. on the Celestial
Sphere
What’s up in the night sky?
The Celestial Sphere
• An imaginary sphere
surrounding the earth,
on which we picture the
stars attached
• Axis through earth’s
north and south pole
goes through celestial
north and south pole
• Earth’s equator
Celestial equator
What’s up for you?
Observer
Coordinates
• Horizon – the
plane you stand on
• Zenith – the point
right above you
• Meridian – the
line from North to
Zenith to south
…depends where you are!
• Your local sky –
your view depends on your location on earth
Look
North in
Westerville
Look
North on
Hawai’i
Star
Maps
Celestial
North Pole –
everything
turns around
this point
Zenith – the
point right
above you &
the middle of
the map
40º
90º
That’s
what
you’d
actually
see!
Confusing?
Experts’
view
Learn to
identify crucial
constellations
Find your way
around the
night sky
At
Noon
Sun at
meridian,
i.e. exactly
south
Moon
setting in
the
Northwest!
Some
hours
later
At
Sunset
A good starting point
• A pair of binoculars and a star map will
keep you busy for a long time – anywhere!
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constellations
Planets
Moon
Orion nebula
Andromeda Galaxy
star clusters
Double stars
…
Low End – Naked Eye Astronomy
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Moon phases
Constellations
Identifying planets
Sun set/rise
Rotation of the Earth (daily/seasonal)
Observe changes as you are at your vacation
location
• Much more …
• Budget: ZERO!
High End – Amateurs contribute to
Scientific progress
• Discover
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Comets
Asteroids
Exoplanets
Supernovae
• Budget: order $10,000
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Telescope(s)
CCD camera
Location, location, location
Time!
Example: Amateur discovers Exoplanet
Brightness/ time
Otterbein Equipment
• Meade LX200, 10”
• Fully computerized, UHTC, electric focuser, etc.
• Celestron 14” telescope
• Celestron 8” telescopes (three)
• digital cameras: Sony DSC-F717, Canon 10D
• and more …
Celestron 14” in shed
Celestron 8” with solar filter
Some “real” astrophotos
• With a telescope and the simplest digital camera
you can shoot amazing astrophotos!
• You basically use the telescope as a telephoto
lens
• Digital cameras supply instant feedback, so the
learning curve is steep!
• Observatory Homepage: http://www.otterbein.edu/dept/PHYS/weitkamp.asp
• Photos at: http://www.otterbein.edu/home/fac/uwtrtt/Observatory/BestPhotos.html
Lunar South Pole Region
(Photo
with the 14”
Celestron
and
Sony DSC
F- 717
Digital
Camera)
Moon
(Photo
with the 8”
Celestron
and
Sony DSC
F- 717
Digital
Camera)
Saturn
(Photo
with the 10”
LX200 and
Sony DSC
F- 717
Digital
Camera)
Saturn and Moons
(Photo
with the 10”
LX200 and
Sony DSC
F- 717
Digital
Camera)
Jupiter with Red Spot
(with C-8
Barlow lens &
full zoom,
Exp. 1/5”,
A2.0, seeing
worsening
from cold
haze, just got
lucky )
Jupiter and Moons
(Photo
with the 8”
Celestron
and
Sony DSC
F- 717
Digital
Camera)
Orion Nebula (M42/M43)
(Photo
with the 10”
Meade LX200
and
Sony DSC
F- 717
Digital
Camera)
Irregular Galaxy (M82)
Dumbbell Nebula (M27)
(photographed with C8, Canon 10D SLR camera, 146 sec exposure, handguided)
M11
• Open Star
Cluster in
Scutum
(with Canon
10D)
Classifying Objects
• Sun and Moon
• Planets and their moons
• Stars and Constellations
– Variable stars
• The Milky Way
• Deep Sky Objects
– Star Clusters (Open and Globular)
– Bright and Dark Nebulae
– Galaxies (used to be called nebulae also)
When to observe which Objects
• The surface features on the Moon are best
seen when the Moon is not full (nor new )
• Observe Jupiter’s four Galilean moons with
binoculars whenever Jupiter’s up
• Small telescope will show Saturn’s rings
• Milky Way can be seen under dark skies
(… already in Madison county)
Ecliptic
The tilt of Earth’s
axis is responsible
for the tilt of the
Sun’s apparent
path with respect
to the
celestial equator
Motion of Sun, Moon and other Planets
•
•
All major bodies in the Solar System move around ecliptic
Slow drift (from W to E) against the background of stars
Motion of the Moon
• Moon shines not by its own light but by reflected
light of Sun
 Origin of the phases of the moon
• Moon revolves around the Earth
• period of revolution = 1
month
Phases of the
Moon (cont’d)
• Moon rotates around
earth in one month
• Moon rotates around
itself in the same time
•  always shows us the
same side!
•  “dark side of the moon”
(not dark at all!)
Motion of the Planets
• Along the
ecliptic as Sun
and Moon
• But: exhibit
weird,
“retrograde”
motion at
times
The heliocentric Explanation of
retrograde planetary motion
See also: SkyGazer
SkyGazer
• A computer program that simulates the
vision of the sky during day and night
Things to observe:
• Set your position on Earth: observe how view of
sky changes as you move E,W, N,S
• Note the distribution of sunlight on Earth!
• Rotation is around Polaris which is not in zenith
Inner and Outer
Planets
• Inner Planets: closer to sun than Earth
– Mercury & Venus
– Always close to sun in the sky
• Outer Planets: further from sun than Earth
– Mars, Jupiter, Saturn, Uranus, Neptune, Pluto
– Best viewing when opposite of sun in the sky
Inner Planets
superior conjunction
Inner planet
eastern
elongation
western
elongation
inferior conjunction
Earth
Outer Planets
quadrature
conjunction
Earth
quadrature
Outer planet
opposition
Close Outer Planet
Size of planet
varies a lot as
Earth moves
Earth
Outer planet
Far-Out Planet
Earth
Size of planet
varies little as
Earth moves
Outer planet
Deep Sky Objects
• Usually faint and/or small
• Best observed under dark skies/ moonless
nights
• Some are binocular objects, some require
sizeable telescopes
Deep Sky Objects: Open Clusters
•Classic example: Plejades (M45)
•Few hundred stars
•Young: “just born”
Still parts of matter
around the stars
Deep Sky Objects: Globular Clusters
• Classic example: Great Hercules Cluster (M13)
• Spherical clusters
• may contain
millions of stars
• Old stars
• Great tool to study
stellar life cycle
From the Rooftop
Plejades in Taurus,
Open Cluster
M92 in Hercules,
Globular Cluster 
Deep Sky Objects: Nebulae
Classic example: Orion Nebula (M 42)
• hot glowing gas
Temperatures ~ 8000K
• Made to glow by
ultraviolet radiation
emitted by young
O- or B-type (hot)
stars located inside
• Color predominantly
red, the color of a
particular hydrogen
emission line (“H”)
Dark Nebulae
• Classic Example: Horsehead Nebula in Orion
Trifid Nebula (M20)
Good example for
dark dust lanes in
front of an emission
nebula
Deep Sky Objects: Planetary Nebulae
• Classic Example: Ring nebula in Lyra (M57)
(Here: “Eye of God” Nebula)
• Dead, exploded stars
• We see gas expanding
in a sphere
• In the middle is the
dead star, a
“White Dwarf”
Eskimo Nebula
Eskimo Nebula: close up
Deep Sky Objects: Galaxies
• Classic example: Andromeda Galaxy (M31)
• “Island universes”
• Made out of billions
of stars and dust
• Very far away
(millions of ly’s)
• Different types:
– Spiral, elliptic, irr.
Deep Sky Catalogues
• Some of the best deep sky objects can be found in the
Messier Catalogue (e.g. M 31)
• Messier (around 1770) catalogued the objects not to
confuse them with comets
• There are 110 Messier Objects
• Other catalogues:
– NGC: new general catalogue (1880) lists 7800 objects
– Caldwell list: 109 best non-messier objects
– Herschel 400: from Herschel’s famous list, early 1800’s
The Night Sky in June
• Shortest Nights and EDT => late observing!
• Early summer constellations are up: Virgo,
Bootes, Hercules, Serpens Caput, Ophiuchus,
• Mars, Saturn still visible early evening, Jupiter late
at night.
Moon Phases
• 6 / 3 New Moon
• 6 / 10 (First quarter Moon)
• 6 / 18 (Full Moon)
• 6 / 26 (Last Quarter Moon)
Today
at
Noon
Sun at
meridian,
i.e.
exactly
south
10 PM
Typical
observing
hour,
early June
Mars
Saturn
Zenith
Big Dipper
points to the
north pole
West
• Saturn near
Praesepe
(M44), an
open star
cluster
• Oops, that
was last
year! Now
Saturn is
here!
East
• Canes
Venatici:
– M51
• ComaVirgo
Cluster
• Globular
Star
Clusters
– M3, M5
South
Virgo and
Coma
with the VirgoComa
galaxy
cluster
VirgoComa
Cluster
• Lots of
galaxies
within a
few
degrees
M87, M88
and M91
East
– Hercules
– Corona
Borealis
– Bootes
Globular Star
Clusters:
•M3
•M5
• M 13
• M 92
Low in
the South
– Virgo
– Corvus
– Libra
Globular Star
Cluster:
•M5
Centaurus
M13: Globular Cluster
These guys will know of our existance in 21,000 years!
Mark your Calendars!
• Next Starry Monday: October 6, 2008, 7 pm
(this is a Monday
• Observing at Prairie Oaks Metro Park:
– Friday, July 11, 2008, 9:15 pm
• Web pages:
– http://www.otterbein.edu/dept/PHYS/weitkamp.asp (Obs.)
– http://www.otterbein.edu/dept/PHYS/ (Physics Dept.)
)