What is it?

Gallery opened 10 Nov 2021

Updated 10 Dec 2021

Andreoli Spitlight image projector updated
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I have wondered for a long time what this thing is. Perhaps someone can tell me?

Left: Unknown item: 1951?

This picture comes from a book titled Curious Moments, pub Konneman 2006, in Germany. The cover says it is an 'archive of the century', and is a collection of photographs from STV-Bild/Das Photoarchiv. Googling for this organisation brings up STV- The Swiss Gymnastics Federation- which does not appear to be relevant.

What on earth is it? At the left it looks like some sort of telescope, with a lens at the end. However, if it is there seems no reason why the rest of the body to the right should be twice the diameter, and even larger at the rightmost end. In the middle there is an arrangement of four rollers that allows the instrument (?) to be moved back and forth a couple of feet in its tubular travelling-frame. At the right there is a big handwheel, of unknown purpose; such handwheels are not usually found on the side of telescopes.

At the top of the body to the right there are what appear to be four angled pipes for drainage, (??) which perhaps suggest chemical engineering.

The caption is as it appears in the book; it suggests 1951 as the date. Further mystery is added by the figure at lower left, wearing some sort of protective clothing. It looks rather like an early WW1 gas-mask, except they only covered the head and were not belted at the waist as shown here. There are no obvious arrangements for breathing, which could be a problem. Oddest of all, there appear to be two blunt antennae protruding just above the eye-pieces. If this is protective clothing, the wearer seems to have forgotten to cover his hands.

Can anyone say what this is? I did a reverse image search but found nothing.


Two correspondents have identified the gear worn by the man as protection for welders, with the 'antennae' above the eye-pieces a second set of dark lenses that can be swung down to deal with very strong lights. There is agreement that it is some sort of optical instrument, probably with a big arc lamp at the right end. That would explain the welding gear for eye protection, and why the hands are not covered.

At the right is some sort of sector-and-roller affair that looks as if it allows the tube to elevate; possibly controlled by the big handwheel. The hooded shape of the main tube suggests it's designed to keep weather off the smaller tube. But if it is an optical thing, why is the main tube so much bigger than the smaller tube with the lens?

My thoughts are hardening that it is some sort of special light-projector; something apart from an ordinary searchlight. Very possibly for projecting images on clouds.

Left: Needle-beam projector: 1935

This projector has some intriguing points of similarity with the mystery item:

  • There is a lamp housing which is about twice the diameter of the tube to the right.
  • There is a relatively long distance between the lamp housing and the end of the tube.
  • There is a handwheel on the side and a rod parallel to the tube which appears to be for focusing by moving the front of the tube in and out.

Source: Popular Science for July 1935.

There is some information on large-format slide-projectors in Wikipedia.

There is an obvious cultural reference; Batman appeared in 1939 and the Bat Signal was first used in 1941.


Left: Cloud image projector: USA 1893

This looks fairly conclusive. The lens is half the diameter, or less, of the arc housing. Note the handwheel for elevation, and what appears to be a smaller handwheel for focusing the lens at the far end of the instrument.

The La Nature article now appears to have been reporting on American work by Lewis Rogers; see below

Source: La Nature 1893

Left: Rogers cloud image projector: USA 1893

Cloud projection experiments in the USA were carried out between 1892 and 1894 by Lewis H. Rogers, of the The Brush Company. The projector was moved to the roof of the Grand Opera in Boston (after initial experiments on Mount Washington) and Rogers experimented with projection onto clouds.

In September 1893, during the Columbia Exhibition in Chicago, the projector, was installed on the roof of the Palace of Arts and Manufactures, at a height of 200 feet. The first demonstration of the cloud projector for VIPs and the Press took place on Sunday, September 24; there was some difficulty in adjusting the new main lens.

This looks very much like the French engraving above; it probably shows the Boston Grand Opera installation. The La Nature article was reporting on these American developments.

Source: The Electrical Engineer 17 January 1894

There is more info here. (in French)

Left: Rogers cloud image projector: USA 1893

According to histv.net, the projector consisted of a fixed focus arc lamp with a reflecting mirror two feet six inches in diameter. The reflector could be operated from below using a chain and a handwheel. (for focusing?) The design to be projected was cut out of cardboard and "placed between the two reflector lenses"; not entirely sure what that means, but it suggests there was a condenser lens in front of the arc lamp, with the other projector lens at the outer end of the device. This is a standard optical layout for slide projectors. The arc lamp was designed to use 150 amps, at 110 volts; that's a hefty 16.5 kiloWatts. The projector weighed nearly two tons.

The French engraving above was clearly taken from this photograph; note the wooden platform is the same.

Source: The Electrical Engineer 17 January 1894


Left: Cloud image projector: USA 1931

The same format; a big-ass arc lamp housing and a much smaller lens at the far end.

Unfortunately the article gives no clue as to who built this. The top line of text on the arc housing says "EXT PROJECTOR"; googling that won't get you anywhere. The other text is not legible.

Source: Popular Science Aug 1931

Thanks to Paul Dunlop for bringing this to my attention and providing the image.


Left: Grindell-Matthews cloud image projector: 1933

This projector was introduced by H Grindell-Matthews, in a rather desperate attempt to make some money. He projected onto clouds "Happy Christmas" and a working clock face. It was not a commercial success, and Grindell-Matthews went bankrupt the following year.

Once more the same format; a big arc lamp housing and a much smaller lens at the far end. However, this time the tube is off-centre with respect to the arc lamp housing, probably to make construction easier. This would have meant having the mirror behind the arc tilted or otherwise offset.

The duct running up the side of the tube is of unknown function; it might have housed a focusing mechanism to move the lens, or it might have ducted cooling air to said lens- there seems to be some sort of outlet near the end of the tube.

The light projector was only a small part of Grindell-Matthews' activities. He is best known for having claimed to have invented a death-ray in 1923, which he had not.

Source: Popular Science Apr 1933

Thanks to Paul Dunlop for bringing this to my attention and providing the image.

Left: Grindell-Matthews cloud image projector: 1933

The Grindell-Matthews projector in action, probably on Hampstead Heath, London.

Source: Popular Science Apr 1933

Left: Grindell-Matthews and clock: 1933

For once we know the exact date of a photograph; 26th January 1933. Mr Grindell-Matthews holds up a clock face, intended for projection onto clouds using his rather-less-than-original invention- a cloud projector he claimed capable of beaming advertisements fifteen miles into the sky. Regrettably, clouds are rarely more than seven miles high. The projector was claimed to have a 15 million candle-power lamp and be capable of enlarging the clock until its hands were a mile long.

Grindell-Matthews appears to be holding the clock by a small round thing which was presumably some sort of motor to make the hands move.

A smaller version of this image appears in the Popular Science article above.

Source: Popular Science Apr 1933


The Spitlight was created in 1955 by Gianni Andreoli of Ticino. The German version of Spitlight, Lichtspucker, literally means 'light-spitter'. Not perhaps the most euphonious of names. The Spitlight was demonstrated in Switzerland, Holland and Monaco, but it made its most impact at the 1956 Winter Olympics in Cortina di Ampezzo.

Left: The Andreoli Spitlight image projector: Switzerland 1955

You didn't point the whole Spitlight, like earlier projectors; there was a swivelling mirror in the front section, as demonstrated by this photograph. The light output was stated as 375,000 lumens. It could project an image 833 x 833 metres across at 6km onto clouds or mountainsides. Nowadays you can buy a hand-held torch that claims to put out 100,000 lumens, more than a quarter of the Spitlight output. Forget about laser pointers, don't look into this thing.

For further comparison, by a long way the brightest (non-laser) beam of light on earth is the Sky Beam at the top of the Luxor Hotel in Las Vegas. It is rated at 42.3 billion candelas, equivalent to 130,000 100-Watt incandescent light bulbs. The beam comes from 39 xenon lamps that are each rated at 7 kW.

A word on units; the lumen measures the total luminous flux in a light beam. The candela allows for the width of the beam, so 1 candela equals 1 lumen per steradian. When a 1 lumen beam illuminates a surface of 1 square meter, this is an illuminance of 1 lux.

There is a Wikipedia page on the Spitlight.

There is more information here.

The instrument was based on a Super Ventarc carbon arc lamp, made by the firm Edgar Gretener AG. This ultra-bright (for its day) source was developed from 1948 onwards, primarily for the Eidophor television projector.

Left: The Andreoli Spitlight image projector: Switzerland 1955

The Spitlight was mounted on a Bedford truck. It always towed a diesel generator (variously described as 120 or 170 HP) to provide the electricity.

There is more information here.

In some ways the Casaba-Howitzer might be considered the ultimate projector. It was powered by an atom bomb.

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