A sensor system comprising: a first optical sub-system including a first plurality of optical elements; a second optical sub-system configured to rotate about a first gimbal axis relative to the first optical sub-system, the second optical sub-system including: an afocal foreoptics configured to receive electromagnetic radiation and to direct a collimated beam of the electromagnetic radiation to the first optical sub-system; characterized by a first coelostat mirror configured to rotate about a second gimbal axis substantially perpendicular to the first gimbal axis and to receive and reflect the electromagnetic radiation; and a second coelostat mirror configured to rotate about a third gimbal axis substantially perpendicular to both the first gimbal axis and the second gimbal axis , and to receive the electromagnetic radiation reflected by the first coelostat mirror and to direct the electromagnetic radiation to the afocal foreoptics , wherein the first coelostat mirror is further configured to rotate around a fourth gimbal axis substantially perpendicular to the second gimbal axis and in a plane of the first coelostat mirror , wherein a rotation of the first coelostat mirror around the fourth gimbal axis prevents a gimbal singularity in which a line of sight direction substantially coincides with the first gimbal axis . a first optical sub-system including a first plurality of optical elements; a second optical sub-system configured to rotate about a first gimbal axis relative to the first optical sub-system, the second optical sub-system including: an afocal foreoptics configured to receive electromagnetic radiation and to direct a collimated beam of the electromagnetic radiation to the first optical sub-system; characterized by a first coelostat mirror configured to rotate about a second gimbal axis substantially perpendicular to the first gimbal axis and to receive and reflect the electromagnetic radiation; and a second coelostat mirror configured to rotate about a third gimbal axis substantially perpendicular to both the first gimbal axis and the second gimbal axis , and to receive the electromagnetic radiation reflected by the first coelostat mirror and to direct the electromagnetic radiation to the afocal foreoptics , wherein the first coelostat mirror is further configured to rotate around a fourth gimbal axis substantially perpendicular to the second gimbal axis and in a plane of the first coelostat mirror , wherein a rotation of the first coelostat mirror around the fourth gimbal axis prevents a gimbal singularity in which a line of sight direction substantially coincides with the first gimbal axis . an afocal foreoptics configured to receive electromagnetic radiation and to direct a collimated beam of the electromagnetic radiation to the first optical sub-system; characterized by a first coelostat mirror configured to rotate about a second gimbal axis substantially perpendicular to the first gimbal axis and to receive and reflect the electromagnetic radiation; and a second coelostat mirror configured to rotate about a third gimbal axis substantially perpendicular to both the first gimbal axis and the second gimbal axis , and to receive the electromagnetic radiation reflected by the first coelostat mirror and to direct the electromagnetic radiation to the afocal foreoptics , wherein the first coelostat mirror is further configured to rotate around a fourth gimbal axis substantially perpendicular to the second gimbal axis and in a plane of the first coelostat mirror , wherein a rotation of the first coelostat mirror around the fourth gimbal axis prevents a gimbal singularity in which a line of sight direction substantially coincides with the first gimbal axis . <EOS>