Abstract: The present invention relates to modeling an external occulter including: providing at least one processor executing program code to implement a simulation system, the program code including: providing an external occulter having a plurality of petals, the occulter being coupled to a telescope; and propagating light from the occulter to a telescope aperture of the telescope by scalar Fresnel propagation, by: obtaining an incident field strength at a predetermined wavelength at an occulter surface; obtaining a field propagation from the occulter to the telescope aperture using a Fresnel integral; modeling a celestial object at differing field angles by shifting a location of a shadow cast by the occulter on the telescope aperture; calculating an intensity of the occulter shadow on the telescope aperture; and applying a telescope aperture mask to a field of the occulter shadow, and propagating the light to a focal plane of the telescope via FFT techniques.

Abstract: A lift apparatus includes a base frame having a pair of ground engaging caster assemblies and a pair of horizontally extending divergent legs each having an inner end attached to the base frame and an outer end with a roller attached thereto, the casters and the rollers permitting the lift apparatus to roll across the ground surface. A dual parallelogram linkage includes a pair of the posts attached to the base frame and is attached to vehicle support arms. An actuator is connected between the linkage and the base frame and is manually actuated to selectively raise and lower the vehicle support arms between a lowered position for engaging and disengaging from a vehicle and a fully raised position.

Abstract: A lift apparatus includes a base frame having a pair of ground engaging caster assemblies and a pair of horizontally extending divergent legs each having an inner end attached to the base frame and an outer end with a roller attached thereto, the casters and the rollers permitting the lift apparatus to roll across the ground surface. A dual parallelogram linkage includes a pair of the posts attached to the base frame and is attached to vehicle support arms. An actuator is connected between the linkage and the base frame and is manually actuated to selectively raise and lower the vehicle support arms between a lowered position for engaging and disengaging from a vehicle and a fully raised position.

Abstract: A lift apparatus includes a base frame having a pair of ground engaging caster assemblies and an upwardly extending center post, and a pair of folding legs each having an inner end pivotally connected to the base frame and an outer end with a roller attached thereto, the casters and the rollers permitting the lift apparatus to roll across the ground surface. A parallelogram linkage includes a portion of the center post and is attached to vehicle support arms. An actuator is connected between the linkage and the base frame. A pumping handle and a power unit are connected to the actuator for selectively activating the actuator to selectively raise and lower the vehicle support arms between a lowered position for engaging and disengaging from a vehicle and a fully raised position a predetermined distance above the ground on which the base frame rests. The legs and the support arms can be moved to a compact storage position when not in use.