Stargazing 101 Evaluation and “Probing the Depths and Comets, Meteors and Auroras” Chapters 6 & 10 April 20, 2010

Last Class Evaluations Blue sheet – for me White sheet – for the mini-course Office Office of Special Programs and Continuing Education Assignments 1.“Stargazing Log” 2.“Phases of the Moon” assignment 3.One-page typed reflection paper on what you learned at the Boonshoft Planetarium 4.One-page typed reflection paper on the most interesting, unusual, or surprising thing that you observed or learned during the course.

Chapter 6 Probing the Depths

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)

Deep-sky Objects Light-year = the distance that light travels in a year at a constant velocity 299,792 kilometers per second (186, miles per second) Ex. Betelgeuse (in Orion) is light years from Earth, which means the light we see tonight left Betelgeuse years ago. Ex. Sirius is 8.7 light years away

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

Double stars Double Double in constellation Lyra Binary double – all part of a single stellar system

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

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

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

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 ) NightWatch, pages 87-90

Open Star Clusters Messier Objects Charles Messier (“mess-yáy” or “me-sE-Á”) French astronomer ( ) Discovered and catalogued a number of objects – star clusters, nebulae and galaxies 110 objects, designated “M” plus a number (ex. M44) M7: M6:

Open Star Clusters New General Catalogue (NGC) Sir William Herschel German-born British astronomer ( ) 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 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 Major Night Sky Magazine, March/April 2005www.gillatt.org The entire constellation of which the Big Dipper is a part

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)

The Pleiades

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

The Hyades and the Pleiades Aldebaran The Pleiades

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

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

Nebulas Orion Nebula – in Orion’s sword Trapezium – four stars at center (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 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 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 Charts Excellent charts on pages 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 autumn Overhead in winter Chart 15

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

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

Chapter 10 Comets, Meteors and Auroras

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

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

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

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

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

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

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.

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

Meteor Showers (April 20, 2010 – “Lyrid Meteors”) NIghtWatch, p. 161

Auroras November 7, 2004

Auroras Midnight, November 7, 2004 Over downtown Dayton

Auroras John Chumack, November 7, 2004 With Big Dipper

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 &ei=O2PnSsqMI5TwlQfV1pEq&q=aurora+borealis& hl=en# &ei=O2PnSsqMI5TwlQfV1pEq&q=aurora+borealis& hl=en#

Looking ahead to the Spring and Summer Skies

Spring Skies 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 Guide Arc to Arcturus and spike to Spica Corvus Regulus, Leo, the Lion

Summer Skies 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 Skies 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 Triangle Vega – Lyra, the harp Deneb – Cygnus, the Swan Altair – Aquila the Eagle Note: Delphinus, the Dolphin

Northern Cross

Using Big Dipper as Guide Draco, the dragon

Arcturus to Vega 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

Information on Constellations Quick Constellation Guide The Stellar Guide Timeless Myths About.com: Space/Astronomy (constellation pictures) Pictures/ Pictures/

Good luck and good stargazing