A spectrograph is used to measure radial velocities. The spectral dispersion is 0.1 Å/pixel. The spectrum of a star is found to be blue-shifted, with a radial velocity of 45 km/s. What is the observed wavelength of an Fe line whose rest wavelength is 4925.6A? By how many pixels is this line shifted on the detector, relative to the position correspond ing to the rest wavelength?

A spectrograph is used to measure radial velocities. The spectral dispersion is 0.1 Å/pixel. The spectrum of a star is found to be blue-shifted, with a radial velocity of 45 km/s. What is the observed wavelength of an Fe line whose rest wavelength is 4925.6A? By how many pixels is this line shifted on the detector, relative to the position correspond ing to the rest wavelength?