ASTRO 1 Lecture 26: 26
Document Summary
Doppler shift of light: you can tell how fast something is moving from the shift of its spectral lines relative to the laboratory standard, when v << c, then. / = v / c. K = 6 nm (v/3000 km/s) ( / 600 nm: shift is generally too small to change the color of the light, doppler shift measures motion directly towards/away from us. Light rays from distant objects are parallel: refraction. Light from every point on an extended object passes through every point in the lens (telescope must take all those parts and put them on one focal point to create image) Curved lens bends lights to focal point. Distance from lens to focal point is focal length: re ection. A concave, parabolic mirror re ects to a focal point: after focal point, an objective lens is needed to make the rays parallel again. Shortcoming of lenses: blue light and red light have different focal points.
