Astronomy 100 Tuesday, Thursday 2:30 - 3:45 pm Tom Burbine [email protected] looks like everybody who wants to get in the class can get in the classCourse MaterialGrading1st HW assignmentOWL website is now runningTutorial (2nd HW assignment)What did we learn last time?Constellations What are they?ConstellationsWhat are the constellations named afterZodiacQuestion:Answer:Question:Answer:Motion of the Sun through the ZodiacQuestion:Answer:Now there are 13 constellations in the zodiac3rd HW assignmentFor example, Ophiuchus What to writeWhere to look for informationTerminology for looking at the skyFinding Celestial PolesCelestial PolesAngular sizeMore precise distancesStar positions change versus latitudeCircumpolar StarsAstronomy 100Tuesday, Thursday 2:30 - 3:45 pmTom [email protected] looks like everybody who wants to get in the class can get in the class• If you have given me your name and ID number, I have forwarded it to the Astronomy secretary• You then need to add yourself to the class in SPIRECourse Material• Course Website: www.xanga.com/astronomy100• Textbook: Stars, Galaxies, and Cosmology, The Cosmic Perspective, 3rd Edition by Bennett, Donahue, Schneider, and Voit•PRS:You need to have an InterWrite PRS transmitter.Grading• 4 in-class exams and a cumulative final• I will drop the lowest test score• The average of the 4 highest scores will be 80% of your grade• 10% of your grade will be your homework score• 10% of your grade will be from PRS1stHW assignment• You need to find an article on astronomy (web, newspaper, magazine)• Print it, copy it, or cut it out• Read it• Write one paragraph on why it is important or why you found it interesting• Staple them together• Write your name and ID number on front page• Write the first three letters of your last name in big letters on front page• Hand it in during next class• You will then get 1 Homework credit!!OWL website is now running• http://owl.oit.umass.edu• Go to Astronomy• LOGIN: ID number• Password: Last Name• To register PRS: Go to Clicker registraion• If you were not originally registered for the course, you will have to go to follow instructions on the site to be able to log onTutorial (2ndHW assignment)• Tutorial to learn how to do HW in OWL• Needs to be done by 11:59 pm on Feb. 3 • You need to get perfect score to get 1 HW credit!• No partial creditWhat did we learn last time?• Universe is big• We will use the metric system• We will use scientific notation• We are moving through spaceConstellationsWhat are they?Constellations• People refer to constellations as a pattern of stars• Astronomers refer to constellations as specific regions of the sky• In 1928, the IAU (International Astronomical Union) decided there were 88 constellations• But many of the constellation names go back thousands of yearsWhat is thisconstellation?OrionBigger the star, the brighter it isOrion was the son of the god of the sea, Poseidon and a great hunter.One story is that he made an enemy of Hera who sent a scorpion to sting him.Orion was restored to health by Ophiuchus, the first doctor of medicine. Another story is that Artemis was tricked by by Apollo to shoot an arrow at Orion. When he died, Poseidon asked Zeus to put him among the stars.What are the constellations named after• 14 men and women• 9 birds •2 insects• 19 land animals• 10 water creatures• 2 centaurs• one head of hair•a serpent• a dragon• a flying horse• a river• 29 inanimate objectsCelestial SphereZodiac•The zodiac is an imaginary belt in the heavens extending approximately 8 degrees on either side of the Sun's apparent path (the ecliptic), that includes the apparent paths of the Moon and the planets Mercury, Venus, Mars, Jupiter, Saturn, Uranus, and Neptune.Question:• Why do all the planets seem to follow the same path?Answer:• The planets, the Earth, and the Sun all tend to fall in the same plane called the eclipticQuestion:• Why is the path of the constellations on the zodiac not on the celestial equator?Answer:• The rotation axis of the Earth is inclined with respect to the eclipticMotion of the Sun throughthe ZodiacShow movieQuestion:• How can do know that the sun is travelling along the zodiac since you can’t see stars during the day?Answer:• One can however figure out where the sun is on the zodiac by noting which is the last constellation of the zodiac to rise ahead of the Sun or the first to set after it.Now there are 13 constellations in the zodiac• Why?• Originally the zodiac was divided into 12 equally spaced “signs”• However, some constellations are big, some are small• When the astronomers redid the boundaries, a 13thconstellation was added to the zodiac3rd HW assignment• I want you to find information on the constellation that represents your zodiacal sign• I want you to hand in a picture of the constellation (can be hand drawn) labeled with three star names and a short paragraph on what the constellation is named after• Write your name and ID number on front page• Write the first three letters of your last name in big letters on front page• Hand it in during next class• You will then get 1 Homework credit!!For example, Ophiuchus• Major stars:• RASALHAGUE (Alpha Oph) • Cebalrai (Beta Oph) • Yed Prior (Delta Oph) • Yed Posterior (Epsilon Oph) • Sabik (Eta Oph) • Marfic (Lambda Oph)RASALHAGUE (Alpha Oph)Sabik (Eta Oph) Yed Prior (Delta Oph)What to write• In Greek myth, Ophiuchus represents the god of medicine, Asclepius. Asclepius was the son of Apollo and was taught by Chiron, the Centaur. He learned how to bring people back from the dead, which worried Hades. The god of the underworld asked his brother Zeus to kill the medicine god. Zeus did strike him dead, but then put the figure of Asclepius in the sky to honor him.Where to look for information• Encyclopedia• Google.com• Wikipedia.com• Astronomy book at the libraryTerminology for looking at the skyFinding Celestial PolesShow MovieCelestial Poles• The altitude of the celestial pole is equal to your latitude• If the altitude of the celestial pole is 50 degrees, you latititude is 50 degreesAngular size• We measure distances in the sky using angles• 180o in the observable skyMore precise distances• 1 degree = 60 arcminutes (symbol ´)• 1 arcminute = 60 arcseconds (symbol ´´)• So something that is 2 degrees, 10