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Northern
Hemisphere
'Standard' Calculator (front) |
Northern
Hemisphere
'Standard' Calculator (back). The indistinct text at the bottom
reads:
Times given are local solar time which may not be official time
and must be converted. For example, in England, 3pm
= 3pm Greenwich Mean Time (GMT) = 4pm British Summer Time (BST)
= 5pm Double Summer Time (DST) |
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Southern
Hemsiphere
'Standard' Calculator (front) - (RH) |
Southern
Hemisphere
'Standard' Calculator
(back - note "Latitude S" on LHS)
Also, there is no guidance about GMT, BST or DST. - (RH) |
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Artificial Light Calculator |
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'Artificial Light'
Calculator (front) |
'Artificial Light'
Calculator (back) |
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The calculators, when
purchased individually, were supplied in small paper envelopes,
such as the one shown above, 7.5cm square.
The 3/- (3shillings, 3s, = 15p) price is clearly marked.
The instructions are shown below.
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A rather more colourful
version of the artificial light calculator was available by the
late 1950s.
But the price had risen to 4/6d = 22.5p
The 1958 instructions (see below) were more detailed.
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BJPA
Review of the Artificial Light Calculator, July 1949, p305 |
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Artificial
Light Calculator ~ French version; courtesy of Daniel Clement |
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Standard
DayLight Calculator ~ French version; Calculateur de Pose Johnson;
courtesy of David Bayliss |
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