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Stargazing 101Stargazing 101Evaluation andEvaluation and
““Probing the Depths and Probing the Depths and
Comets, Meteors and Auroras”Comets, Meteors and Auroras”Chapters 6 & 10Chapters 6 & 10
April 20, 2010April 20, 2010
Last ClassLast Class
• Evaluations• Blue sheet – for me• White sheet – for the mini-course Office
• Office of Special Programs and Continuing Education
• Assignments1. “Stargazing Log”2. “Phases of the Moon” assignment3. One-page typed reflection paper on what you learned
at the Boonshoft Planetarium4. One-page typed reflection paper on the most
interesting, unusual, or surprising thing that you observed or learned during the course.
Chapter 6Chapter 6
Probing the DepthsProbing the Depths
Deep-sky ObjectsDeep-sky Objects • Deep-sky objects – objects beyond
our solar system • Most objects you can see with your naked
eye are within our Milky Way Galaxy• “What is the one naked-eye exception?”
• Stars will always be nothing more than a point of light, “no matter how large the instrument or what magnification is used to observe a star.” (NightWatch, p. 84)
Deep-sky ObjectsDeep-sky Objects
• Light-year = the distance that light travels in a year at a constant velocity• 299,792 kilometers per second
(186,282.397 miles per second) • Ex. Betelgeuse (in Orion) is
427.47 light years from Earth, which means the light we see tonight left Betelgeuse 427.47 years ago.
• Ex. Sirius is 8.7 light years away
http://antwrp.gsfc.nasa.gov/
Double StarsDouble Stars• Hundreds of double stars can be observed
with naked-eyes and binoculars• Thousands with telescopes
• Binary systems – a pair of gravitationally associated stars
• Optical doubles – a chance alignment of stars • One is usually much closer to us than the other• NightWatch, pages 84-85
Double starsDouble stars
• Double Double in constellation Lyra• Binary double – all part of a single stellar system
www.weasner.com
Double StarsDouble Stars• Albireo – Double stars (optical) in the constellation
Cygnus, the Swan (summer and autumn)• The larger star is orange and smaller star is blue
http://zimmer.csufresno.eduwww.jb.man.ac.uk
Double StarsDouble Stars• Mizar and Alcor – are double stars in the handle
of the Big Dipper (optical)• Second stars from the end of the handle• With naked eye or binoculars
www.astropix.com
Double StarsDouble Stars
• Mizar and Alcor • Mizar itself is a double
star (binary)• Alcor• Mizar
• The Meade telescope at the UFO can separate the two stars of Mizar
www.perezmedia.net
Open Star ClustersOpen Star Clusters• Groups of a few dozen to thousands of
stars “kept in huddle together by their mutual gravity.” (p. 87)
• “At least 20 open star clusters are easy targets for binoculars…” (p. 87-88)
• NightWatch, pages 87-90
Open Star ClustersOpen Star Clusters• Messier Objects
• Charles Messier (“mess-yáy” or “me-sE-Á”)
• French astronomer (1730-1817)• Discovered and catalogued a
number of objects – star clusters, nebulae and galaxies
• 110 objects, designated “M” plus a number (ex. M44)
M7: http://apod.nasa.com
M6: http://apod.nasa.com
Open Star ClustersOpen Star Clusters
• New General Catalogue (NGC)• Sir William Herschel• German-born British astronomer (1738-1822) • Catalogued many galaxies and other space
objects, including Messier Objects• Many galaxies, star clusters, etc. now have
more than one name/designation• Herschel also discovered Uranus
Open Star ClustersOpen Star Clusters
• The Big Dipper Cluster• All but two of the stars
are part of a star cluster• Alkaid and Dubhe
• The other five stars are all related
• “Believed to be born in the same region of space about 200 million years ago.” (NightWatch, p.88)
Night Sky Magazine, March/April 2005
Ursa MajorUrsa Major
Night Sky Magazine, March/April 2005 www.gillatt.org
The entire constellation of which the Big Dipper is a part
Open Star ClustersOpen Star Clusters• The Pleiades (M45)
• Just under 400 light-years away• Often mistaken for the Little Dipper • Sometimes called the Seven Sisters• Some people can see 6-11 stars with naked eye• Beautiful in binoculars
• With a telescope, a hundred + stars can be seen
• “The approximately 400 stars in this cluster were all born about 20 million years ago.” (NightWatch, p. 88)
The PleiadesThe Pleiades
www.apod.nasa.gov
Open Star ClustersOpen Star Clusters• The Hyades
• In the constellation Taurus, the Bull• Just to the right of Aldebaran
The Hyades and the PleiadesThe Hyades and the Pleiades
Aldebaran
The Pleiades
www.starryskies.com
NebulasNebulas• Vast clouds of gas and dust around the
galaxies• A galaxy’s maternity ward
• Where new stars are born
• Bright stars sometimes light up the gases and dust for spectacular views with telescopes• NightWatch, pages 90-92
NebulasNebulas• Orion Nebula – in
Orion’s sword• Visible to the naked
eye – looks like an out-of-focus star
• Telescopes – reveal individual stars
• The best-known and brightest nebula• Nearest bright nebula• About 1,400 light
years away
www.oobleck.ifa.hawaii.edu
NebulasNebulas• Orion Nebula – in Orion’s
sword• Trapezium – four stars at center
• http://stardate.org (January 19, 2004)
• Top photo – what you might see in a telescope – looks black and white
• Bottom photo – long exposure astrophotography, reveals colors that our eyes are not sensitive to in night vision.
NightWatch, p. 95, 85
Averted VisionAverted Vision• Used when observing any low-light object• “The concept of averted vision is to concentrate
on the celestial object without looking directly at it. With the object of interest centered in the eyepiece field, direct your gaze toward the field’s edge.• It works because the eye’s visual receptors away from
the central axis of vision are more sensitive to dim light.” (NightWatch, p. 92)
• Central receptors (cones) are mostly color vision• Remember cones and rods in the retina of your eye
Globular Star ClustersGlobular Star Clusters• Look like fuzzy stars with
naked eye and binoculars• In telescopes they appear as
concentrated balls of light gradually fading off at the edge
• Cluster in Hercules (M13) • Cluster in Sagittarius (M22)
• Both are easy targets with binoculars
• Both have up to two million stars
The Cluster in Hercules
as seen using an 8-inch
telescope
The Cluster in Hercules
as seen using an 15-inch telescope
NightWatch, p. 92
Using Deep-Sky Using Deep-Sky ChartsCharts
• Excellent charts on pages 97-119 in text• Winter (#15-19) and Spring charts (#1-5)
• BlackBlack = Names: stars and constellations; deep sky objects
• BlueBlue = Observing information: type or class of object; magnitude; double- and multiple-star data; general appearance; instrumentation needed
• RedRed = Descriptive astrophysical information: distance; actual size; luminosity; classification
All year; best late winter
through summer NightWatch, p. 100
Overhead in winter
In the east in autumnOverhead in winter
Chart 15
Northeast in springOverhead in summerNorthwest in autumn NightWatch, p. 109
CenterOf theMilkyWay
Seen near southern horizon mid- to late-summer
NightWatch, p. 107
Chapter 10Chapter 10
Comets, Meteors Comets, Meteors
and Aurorasand Auroras
John Chumack: Comet Bradfield, May 2004, Yellow Springs, OH Galacticimages.com
CometsComets
CometsComets
• “Comets are essentially flying mountains of ice left over from the formation of the giant planets Uranus and Neptune.” (NightWatch, p. 156)• In orbits beyond the orbits of
Neptune and Pluto• They orbit the Sun in large
elliptical orbits that sometimes take centuries or millennium to make one loop.
NightWatch, p. 159
CometsComets
• “As they near the Sun, the cometary ice begins to be vaporized by sunlight. In the vacuum of space, the vapors create a huge cloud of gas and dust that is many times the size of Earth.” (NightWatch, p. 156)
NightWatch, p. 157
CometsComets• The most recent
easily visible comet was Hale-Bopp, which came closest to the Earth in late March and early April 1997
• Comets are named after the first two persons who discovered them and report them.
NightWatch, p. 157
MeteorsMeteors• We call them shooting stars or
falling stars but, “meteors have nothing to do with stars. They are tiny bits of space debris so small that thousands could fit in your hand.” (NightWatch, p. 160)
• They burn up as they enter the Earth’s atmosphere at very high speeds
NightWatch p. 161
MeteorsMeteors
• Meteor = the bright streak of light seen when a small bit of space debris burns up in the Earth’s atmosphere.
• Meteoroid = a small chunk of matter in space that could become a meteor.
• Meteorite = a piece of debris that survives the descent through the Earth’s atmosphere and reaches the surface. • NightWatch, p. 160
MeteorsMeteors• On the average night you can see 3-4 meteors an
hour.• Best time to see the most meteors is between 1:00 am
and dawn• When the Earth is rotated “face first” into the shower
• The meteors are like bugs hitting the windshield of a car
• Bugs don’t splatter on the side and rear windows
• Author suggests using padded, reclining lawn chairs and blankets• Binoculars and telescopes are useless – you want to
see as much of the sky as you can.
Meteor ShowersMeteor Showers
• Annual meteor showers occur when left over debris from comets intersect our orbit around the Sun.
NightWatch, p. 160
Meteor ShowersMeteor Showers
• http://www.stardate.org (April 20, 2010 – “Lyrid Meteors”)
NIghtWatch, p. 161
AurorasAuroras November 7, 2004
AurorasAuroras Midnight, November 7, 2004Over downtown Dayton
AurorasAuroras John Chumack, November 7, 2004With Big Dipper
AurorasAuroras
• Aurora Borealis or northern lights. • Auroras are caused by energetic particles blasted in
the Earth’s direction by eruptions on the Sun. • The particles are deflected by the Earth’s magnetic fields and
enter the Earth’s atmosphere over the magnetic poles• The particles stimulate gases in the upper atmosphere.
• When stimulated:• Oxygen emits a greenish white light or red hue • Nitrogen produces a bluish tint.
• http://video.google.com/videoplay?docid=2631078790090750578&ei=O2PnSsqMI5TwlQfV1pEq&q=aurora+borealis&hl=en#
Looking ahead to the Looking ahead to the Spring and Summer Spring and Summer
SkiesSkies
Spring Spring SkiesSkies
• Big Dipper• Polaris in the Little
Dipper• Arcturus in Boötes,
the Herdsman• Spica in Virgo, the
Virgin• Corvus, the Crow• Regulus in Leo, the
Lion
Using Big Dipper as GuideUsing Big Dipper as Guide
Arc to Arcturus and spike to Spicahttp://my.execpc.com
Corvus
Regulus, Leo, the Lion
Summer Summer SkiesSkies
• Summer Triangle• Vega in Lyra, the Lyre• Deneb in Cygnus, the
Swan • Altair in Aquila, the
Eagle
• Northern Cross• Cygnus, the Swan
• Delphinus, the Dolphin
• Draco, the Dragon
NightWatch, p. 51
Summer Summer SkiesSkies
• Arcturus to Vega,• Corona Borealis,
the Northern Crown
• Hercules, the Strongman
• Saggitarius, the Archer
• Antares, in Scorpius, the Scopion
• Libra, the Scales NightWatch, p. 51
Summer TriangleSummer Triangle
• Vega – Lyra, the harp
• Deneb – Cygnus, the Swan
• Altair – Aquila the Eagle
• Note: Delphinus, the Dolphin
http://vortex.accuweather.com
Northern CrossNorthern Cross
http://cdn-write.demandstudios.com
Using Big Dipper as GuideUsing Big Dipper as Guide
Draco, the dragonhttp://my.execpc.com
Arcturus to Arcturus to VegaVega
• 1/3 of the way points to Corona Borealis• The Northern Crown
• 1/3 more, points to the keystone of Hercules• M13 is the Hercules
Star Cluster• Visible with binoculars
• 1/3 more, points to Vega
http://media.skyandtelescope.com
Information on Information on ConstellationsConstellations
• Quick Constellation Guide• http://astronomyspace.suite101.com/article.cfm/quick_constellation_guide
• The Stellar Guide• http://www.botproductions.com/stellar/index.html
• Timeless Myths• http://www.timelessmyths.com/classical/stars.html
• About.com: Space/Astronomy (constellation pictures)• http://space.about.com/od/starsplanetsgalaxies/ig/Constellations-Pictures/
Good luck
and good stargazing