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Stargazing 101

Stargazing 101. “Probing the Depths and Comets, Meteors and Auroras” Chapters 6 & 10 October 27, 2009. What did you see this past week ?. What did we see at the farm? Put in your log book. Homework: Phases of the Moon.

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Stargazing 101

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  1. Stargazing 101 “Probing the Depths and Comets, Meteors and Auroras” Chapters 6 & 10 October 27, 2009

  2. What did you see this past week ? • What did we see at the farm? • Put in your log book

  3. Homework: Phases of the Moon • We are in the middle of your second opportunity to see the Moon’s phases • October 19 – November 2 • Not due until the last class, next week, November 3, 2009.

  4. Homework: Phases of the Moon

  5. Homework: Phases of the Moon

  6. Chapter 6 Probing the Depths

  7. Deep-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)

  8. Deep-sky Objects • Light-year = the distance that light travels in a year at a constant velocity • 186,282,397 miles per second • Ex. Vega (Lyra) is 25 light years from Earth • Which means the light we see tonight left Vega 25 years ago • Ex. Deneb (Cygnus) is 1,600 light years away • Ex. Altair (Aquila) is 16.8 light years away http://2.bp.blogspot.com

  9. Double 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

  10. Double stars • Double Double in constellation Lyra • Binary double – all part of a single stellar system www.weasner.com

  11. Double Stars • Albireo – Double stars (optical) in the constellation Cygnus, the Swan (summer and autumn) • The larger star is orange and smaller star is blue www.jb.man.ac.uk http://zimmer.csufresno.edu

  12. Double 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

  13. Double 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

  14. Open 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

  15. Open 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

  16. Open 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

  17. Open Star Clusters • The Big Dipper Cluster • All but two of the stars are part of a star cluster • Alkaid and Dubhe – and the two ends • 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

  18. Ursa Major The entire constellation of which the Big Dipper is a part Night Sky Magazine, March/April 2005 www.gillatt.org

  19. Open 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)

  20. The Pleiades www.apod.nasa.gov

  21. Open Star Clusters • The Hyades • In the constellation Taurus, the Bull • Just to the right of Aldebaran

  22. The Hyades and the Pleiades Aldebaran The Pleiades www.starryskies.com

  23. Nebulas • 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

  24. Nebulas • 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

  25. Nebulas • 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

  26. Averted 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

  27. Globular Star Clusters The Cluster in Hercules as seen using an 8-inch telescope • 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 15-inch telescope NightWatch, p. 92

  28. Using Deep-Sky Charts • Excellent charts on pages 97-119 in text • Winter (#15-19) and Spring charts (#1-5) • Black = Names: stars and constellations; deep sky objects • Blue= Observing information: type or class of object; magnitude; double- and multiple-star data; general appearance; instrumentation needed • Red = Descriptive astrophysical information: distance; actual size; luminosity; classification

  29. All year; best late winter through summer NightWatch, p. 100

  30. Autumn, Winter and Spring

  31. Northeast in spring Overhead in summer Northwest in autumn NightWatch, p. 109

  32. In the east in autumn Overhead in winter Chart 15

  33. Overhead in winter

  34. Mid-winter to early spring

  35. Center Of the Milky Way Seen near southern horizon mid- to late-summer NightWatch, p. 107

  36. Chapter 10 Comets, Meteors and Auroras

  37. Comets John Chumack: Comet Bradfield, May 2004, Yellow Springs, OH Galacticimages.com

  38. Comets • “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

  39. Comets • “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

  40. Comets • 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

  41. Meteors • 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

  42. Meteors • 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

  43. Meteors • 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.

  44. Meteor Showers • Annual meteor showers occur when left over debris from comets intersect our orbit around the Sun. NightWatch, p. 160

  45. Meteor Showers • http://www.stardate.org(November 16, 2004) NIghtWatch, p. 161

  46. Auroras November 7, 2004

  47. Midnight, November 7, 2004 Over downtown Dayton Auroras

  48. John Chumack, November 7, 2004 With Big Dipper Auroras

  49. Auroras • 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#

  50. Looking ahead to the Winter Skies

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