An optical sensor system having an extended elevation field of view and in which the optics are configured around an all-reflective four-mirror reimaging anastigmat used for afocal foreoptics and an all-reflective five-mirror reimaging anastigmat used for imaging optics. One example of an optical sensor system includes afocal foreoptics configured to receive and collimate electromagnetic radiation, the afocal foreoptics including an all-reflective, reimaging four-mirror anastigmat, an imaging detector, focal imaging optics positioned between the afocal foreoptics and the imaging detector and configured to receive the collimated beam of electromagnetic radiation from the afocal foreoptics and to focus the beam of electromagnetic radiation onto the imaging detector, the focal imaging optics including a reimaging five-mirror anastigmat, wherein a field of view of the system is determined at least in part by a combination of the afocal foreoptics and the focal imaging optics and covers at least 5 degrees in elevation.