ASTR 1P01 Lecture Notes - Angular Diameter

77 views1 pages

coffeemammoth127

13 Oct 2012

School

Department

Course

Professor

For unlimited access to Class Notes, a Class+ subscription is required.

coralcrow477 and 10 others unlocked

ASTR 1P01 Full Course Notes

Verified Note

29 documents

Document Summary

Proposed a theory that the earth is rotation on its axis and revolving around the sun. Which was based on observations: he concluded that the sun must be a much greater distance than the moon. He argued that if those distances were comparable one would observe the following: When one observes the first quarter moon the angle of the earth and the moon is at 90 degrees. But these intervals are nearly the same. By measuring time between the quarter phases he determined angle a to be. 87 degrees (the actual value is 89 degrees and 57 minute of arc) A/c = distance to the moon/distance to the sun = 1/20 (the actual value is. 1/400 = 384,000km/150,000,000 km) then he concluded that the diameter of the sun must be 20 times the diameter of the moon because they both have the same angular size. Diameter of the moon/ diameter of the sun = d moon/d sun = 1/20.

Related Questions

Astronomy Parallax Lab

SCENARIO: Your lab group is planning an expedition to measure the distance to Mars by carefully measuring its position in the sky from two locations simultaneously when it is next at “opposition” (that is, when it is exactly opposite from the sun in the sky) on October 13, 2020. For the best, and most straightforward distance determination with the parallax method, Mars should be high in the sky (as near to your zenith as possible). This can be done by observing Mars: (a) from locations whose LATITUDES are similar to the DECLINATION of Mars at the date of measurement and (b) at the time of night when Mars is highest in the sky.

1a). Determine the Sky Coordinates of Mars on the date of opposition. The relevant coordinate is the Declination (RA/DE J2000 coordinates should be used) – this is the sky coordinate analogous to Latitude on the Earth’s surface. (Note, it is ok to determine these coordinates for Mars from anywhere on Earth for this initial measurement)

Mars DECLINATION on October 13, 2020: ___________________________

Your lab team needs to send observers to two cities that:

(a) have latitudes that are similar to the declination of Mars on that date (within 20 degrees); and

(b) have nearly the same longitude (that is, are nearly due North-South from each other (hint, you will need to go close to the equator!).

1b). Choose two of the cities below and use google maps, google earth or another online resource to record their names and Latitudes.

Melbourne, Australia	Kampala, Uganda	Tokyo, Japan
Omaha, NE, USA	Mumbai, Italy	Khartoum, Soudan

1c). At what time should you measure the sky coordinates (right ascension and declination) to get the most accurate possible parallax distance?

plumantelope954

ASTR 1P01 Lecture Notes - Angular Diameter

ASTR 1P01 Full Course Notes

Document Summary

Get access

Related Documents

ASTR 1P01 Lecture Notes - Angular Diameter

ASTR 1P01 Chapter Notes - Chapter 2: Gravitational Constant, Centripetal Force, Net Force

ASTR 1P01 Lecture Notes - Heel Stone, Angular Diameter, Mural Instrument

Related Questions