Abstract: Apparatus for and a method of displaying a laser beam are provided. The apparatus comprises an elongate chamber which has a viewing window and which is filled with a clear aqueous suspension of a water-dispersible polymer. The laser beam is displayed by projecting it into the suspension-filled chamber through one end of the chamber.

Abstract: Secured to the barrel of a reflecting telescope is a large mounting ring the axis of which is perpendicular to the barrel axis. The mounting ring extends from an intermediate location on one side of the barrel, around the mirror end of the telescope, and back to an intermediate location on the opposite side of the barrel. The combination of the ring and barrel has its center of gravity approximately at the location of the ring axis. The ring is supported in a cradle on frictional pads. Because the telescope is well-balanced, friction alone can be relied upon to hold the telescope in any desired elevational position. An undercut circumferential groove is provided in the periphery of the mounting ring, and rollers within the undercut groove urge the ring against the frictional pads. The force with which the ring is urged against the pads can be adjusted in order to vary the degree of friction, and also to lock the telescope at a desired elevation.

Abstract: In a reflecting telescope, a diagonal mirror is supported by a spider comprising four thin flexible metal vanes secured to a mirror carrier by axially slotted pins which are rotatable for adjusting vane tension. These vanes provide an extremely stable mirror support, which exhibits low obscuration and minimizes the effect of diffraction spikes.

Abstract: A stable tripod for an optical telescope comprises a head having an inwardly facing circular side wall, three legs, each having a shoe located at its upper end adapted to engage and push outwardly against the circular wall and having a lower end for engaging a surface upon which the support rests, means cooperating with said legs and providing a pivot whereby motion of the lower ends of said legs in an inward direction results in outward motion of the shoes against the wall, and means for urging the lower ends of the legs inwardly in order to urge the shoes tightly against the wall.