PPT-Measuring Parallax

Parallax is the apparent displacement of an object against the background when seen from two different perspectives Definition of Parallax To measure the distance to a star astronomers measure the parallax shift of the star using 2 points of view that are as far apart as possibleat opposite sides of Earths orbit. Copyright Microlensing. Planetary Systems.. Scott Gaudi. Matthew Penny. (OSU). WFIRST . Microlensing. Survey.. Microlensing. Survey Dataset. . Properties.. . ~. 3. sq. deg.. ~432 days.. ~80% of the area will have 2 million seconds of integration time.. This triangle should be 4,500 times longer!. d . (distance to star) . is in parsec units . 1 parsec = 206,265 . x. 1 A.U.. ab. . (distance Earth to Sun) . has to be in Astronomical Units (A.U.). p. Key Ideas. Distance is the most important & most difficult quantity to measure in Astronomy. Method of Trigonometric Parallaxes. Direct geometric method of finding distances. Units of Cosmic Distance:. Introduction. Trigonometric Parallax . Spectroscopic Parallax . Cepheid Variables . Type Ia Supernovae. Tully-Fisher Relationship. Hubble’s ‘Law’ . Trigonometric Parallax. While fundamental, this method is very limited in terms of how far away one can use it. For large numbers of star, ground-based measurements of parallax do not get beyond about 20 pc, although on individual objects this can be extended to about 100 pc (with much effort). . Copyright Copyright . Microlens. Detection of a Massive Remnant in a Well-separated Binary . . Yossi . Shvartzvald. . Jet Propulsion Laboratory, . California Institute of Technology. Explain what parallax is. Give an example how parallax occurs. Locate an image in a plane mirror. Optics - Parallax. Parallax is a difference in the apparent position of an object due to the motion of an observer.. - warnings and caveats -. X. . Luri. (U. Bastian). Scientist’s dream. Error-free data. No random errors. No . biases. No correlations. Complete sample. No censorships. Direct measurements. No transformations. - warnings and caveats -. X. . Luri. (U. Bastian). Scientist’s dream. Error-free data. No random errors. No . biases. No correlations. Complete sample. No censorships. Direct measurements. No transformations. Distances:. The Principle. . ‘. Real Life. ’. Distance . Determinations . We . use various . ways; . y. ou can think . of . several! For instance, you notice that a car down the road ‘looks small’,. OGLE . microlenses. with . astrometric. . microlensing. Noé. Kains . (. STScI. ). with . Kailash. . Sahu. , . Jay Anderson, . Andrzej. . Udalski. , . Annalisa . Calamida. , . Stefano . Casertano. - warnings and caveats -. X. . Luri. (U. Bastian). Scientist’s dream. Error-free data. No random errors. No . biases. No correlations. Complete sample. No censorships. Direct measurements. No transformations.