Welcome to Starry Monday at Otterbein Astronomy Lecture
Welcome to Starry Monday at Otterbein Astronomy Lecture Series -every first Monday of the month. June 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! – 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: – – 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! – constellations – Planets – Moon – Orion nebula – Andromeda Galaxy – star clusters – Double stars –…
Low End – Naked Eye Astronomy • • • 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 – – Comets Asteroids Exoplanets Supernovae • Budget: order $10, 000 – – Telescope(s) CCD camera Location, location Time!
Example: Amateur discovers Exoplanet Brightness/ time
Otterbein Equipment • Meade LX 200, 10” • Fully computerized, UHTC, electric focuser, etc. • Celestron 14” telescope • Celestron 8” telescopes (three) • digital cameras: Sony DSC-F 717, Canon 10 D • 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/Best. Photos. 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” LX 200 and Sony DSC F- 717 Digital Camera)
Saturn and Moons (Photo with the 10” LX 200 and Sony DSC F- 717 Digital Camera)
Jupiter with Red Spot (with C-8 Barlow lens & full zoom, Exp. 1/5”, A 2. 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 (M 42/M 43) (Photo with the 10” Meade LX 200 and Sony DSC F- 717 Digital Camera)
Irregular Galaxy (M 82)
Dumbbell Nebula (M 27) (photographed with C 8, Canon 10 D SLR camera, 146 sec exposure, handguided)
M 11 • Open Star Cluster in Scutum (with Canon 10 D)
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: Sky. Gazer
Sky. Gazer • 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 (M 45) • Few hundred stars • Young: “just born” Still parts of matter around the stars
Deep Sky Objects: Globular Clusters • Classic example: Great Hercules Cluster (M 13) • Spherical clusters • may contain millions of stars • Old stars • Great tool to study stellar life cycle
From the Rooftop Plejades in Taurus, Open Cluster M 92 in Hercules, Globular Cluster
Deep Sky Objects: Nebulae Classic example: Orion Nebula (M 42) • hot glowing gas Temperatures ~ 8000 K • 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 (M 20) Good example for dark dust lanes in front of an emission nebula
Deep Sky Objects: Planetary Nebulae • Classic Example: Ring nebula in Lyra (M 57) (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 (M 31) • “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 (M 44), an open star cluster • Oops, that was last year! Now Saturn is here!
East • Canes Venatici: – M 51 • Coma. Virgo Cluster • Globular Star Clusters – M 3, M 5
South Virgo and Coma with the Virgo. Coma galaxy cluster
Virgo. Coma Cluster • Lots of galaxies within a few degrees
M 87, M 88 and M 91
East – Hercules – Corona Borealis – Bootes Globular Star Clusters: • M 3 • M 5 • M 13 • M 92
Low in the South – Virgo – Corvus – Libra Globular Star Cluster: • M 5 Centaurus
M 13: 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. ) )
- Slides: 75