Transcript Document
Welcome to Starry Monday at Otterbein Astronomy Lecture Series -every first Monday of the monthFebruary 7, 2005 Dr. Uwe Trittmann Today’s Topics • Famous Telescopes • Objects worthy to be observed • The Night Sky in February Feedback! • Please write down suggestions/your interests on the note pads provided • If you would like to hear from us, please leave your email / address • To learn more about astronomy and physics at Otterbein, please visit – http://www.otterbein.edu/dept/PHYS/weitkamp.asp (Obs.) – http://www.otterbein.edu/dept/PHYS/ (Physics Dept.) Telescopes • From Galileo to Hubble Telescopes • Light collectors • Two types: – Reflectors (Mirrors) – Refractors (Lenses) Famous Telescopes - Galileo • Galileo’s first telescope was 3x magnifying • his last one 32 x Famous Telescopes -Newton • First Reflector ever • Built around 1670 • After this: gargantuan Telescopes! Famous Telescopes - Hevelius Rooftop observatory of Johannes Hevelius (1670) Famous Telescopes - Hevelius 60 inch ^ 140 inch Famous Telescopes - Herschel Herschel detected Uranus (1781) Famous Telescopes – Lord Ross • 72 inch Reflector • built during potato famine in Ireland • Largest Telescope until Mt Wilson (1917) Famous Telescopes – Yerkes • Largest Refractor Telescope ever • 40 inch lens • Built 1897 Famous Telescopes – Mt Palomar • 5 Meter Telescope – Huge and heavy mirror • On Mt. Palomar in California Famous Telescopes – Hubble Space Telescope • In orbit around earth • No limitations due to earth’s atmosphere • Brilliant pictures Famous Telescopes – Arecibo Radio Telescope • Located in Puerto Rico • 300m diameter • Receives Radio waves • Built 1963 • SETI Famous People Hubble in prime focus of Mt Palomar. Einstein visits Mt Wilson Hubble detected the Expansion of the Universe Proof of Einstein’s General Relativity Theory Largest Earth-Based Telescopes • Keck I and II, Mauna Kea, Hawai’i – 36 1.8 m hexagonal mirrors; equivalent to 10 m – Above most of atmosphere (almost 14,000 ft ASL) – Operating since 1993 Visiting Mauna Kea Mauna Kea • Elevation: 14,000 ft. • Oxygen: 60% • Freezing on top, snorkeling at sea level • Road: strictly 4 wheels! Mauna Kea Maui • 325 observing days per year! • Darkest skies on the planet! The biggest Telescopes in the World Sunset on Mauna Kea 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 (…but already in Madison county) 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 Observing Stellar Evolution: Example 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”) Friday Night • 27 seconds exposure Friday Night • 87 seconds exposure 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” Friday Night: 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 February • The sun is still very low in the sky -> long nights! • Winter constellations (Orion, Gemini, Taurus,…) contain many bright stars and objects • Saturn was in Opposition last month (i.e. at its brightest) Moon Phases • Today (Waning crescent, 2%) • 2 / 8 (New Moon) • 2 / 15 (First Quarter Moon) • 2 / 28 (Full Moon) • 3 / 3 (Last Quarter Moon) Today at Noon Sun at meridian, i.e. exactly south 10 PM Typical observing hour, early January no Moon Saturn! Midnight Jupiter Zenith High in the sky: Perseus and Auriga with Plejades and the Double Cluster NorthEast Big Dipper points to the north pole Due South The Winter Constellations – – – – – Orion Taurus Canis Major Gemini Canis Minor East Spring Constellations - Cancer - Leo - Hydra Deep Sky Objects: - Beehive Cluster (M44) Mark your Calendars! • Next Starry Monday at Otterbein: March 7, 2005, 7 pm (this is a Monday • We’ll talk about Mars Missions and more… • Web pages: – http://www.otterbein.edu/dept/PHYS/weitkamp.asp (Obs.) – http://www.otterbein.edu/dept/PHYS/ (Physics Dept.) )