Das, H.K.Kohok, AbhayTandon, S. N.2012-03-072012-03-072011-07-06http://hdl.handle.net/11007/881Based on the transfer pupil technique we develop a method to measure the lower order aberration coe±cients for optical telescopes; the method makes use of a Hartmann mask in a spectrograph for sampling the wavefront at di®erent locations.enSpectrographOptical telescopeArticle