Last year we looked at an RAF emergency heliograph here. That example measured 3” across, however there was also a smaller, half size heliograph that was also issued. Apart from the size difference this was identical to the other heliograph. It was issued in a small cotton pouch, secured with a tie string and with the word ‘heliograph’ stamped on the outside:

Undoing the tie allowed the pouch to be opened and there was a pocket for the mirror and another for the little sighting tab:

The two parts of the set are joined together by a short piece of cord. The mirror has a central hole in it for sighting purposes and has a half thickness etched cross on the mirrored surface:

A label with operating instructions is attached to the rear:

The sighting bar is painted white and is marked with both a /|\ mark and an RAF stores code:

It is very hard to get an idea of scale just from the photographs above, so to demonstrate the two different sizes, here is this smaller heliograph alongside the other, larger pattern:

The difference in size is quite marked and it is clear that the smaller pattern would be much easier to include in a survival tin, although its smaller surface area would make it harder to use effectively to signal an aircraft above.