(from Datasheet, 1969)
These new Mark II versions of the original pressure die-cast spotlights all have four built-in beam shaping shutters so that the characteristics of the Profile optical system can be used to the full. Each of the four externally operated shutters can be angled through more than 90° around the optical axis so that the evenly distributed beam can be accurately contained within any four or three-sided area even when projected from an acute angle.

NEW: DOWNLOAD Data sheet - Patt 23 II - 1969 (PDF)

1) 7-in. diameter faceted ellipsoidal reflector
2) Medium prefocus lampholder
3) 7-in. diameter annular reflector
4) Gate runners for beam-shaping mask or optional addition of an iris or purpose-made mask
5) Fixed aperture diaphragm to intercept stray light; also position for second 3½ x 5-in. lens for Patt 23W
6) 3½ x 5'in. lens for Patt 23, or 3½ x 4'in. Fresnel lens for Patt 23F, in sliding lens tube provided with safety chain
7) Double colour frame runners
8) Hinged rear door for interior access

Pattern 23 Baby Mirror Spot 250 or 500 Watts
(Also Narrow Beam Patt.23N and Wide Angle Patt.23W)
This small, compact lantern which gives a clear-cut beam of any required shape free of stray or ghost light, has been tooled for mass production die-casting and consequently represents exceptional value.
Light Distribution
The standard lantern with a single lens gives beam angles up to 22 degrees. The shape and size of beam are varied by using one of the four standard diaphragms, a special mask, an adjustable type mask, or iris diaphragm.
The beam angle may be increased to 37 degrees (but the intensity halved and the useful life of the colour medium noticeably reduced) by fitting an extra lens in the rear of the lens tube.
The beam angle may be decreased to 11 degrees max., and intensity increased over three times the standard, by fitting a front with a 6-in. lens, instead of the standard tube. The lantern is then suitable for long throws.