Paralleloscope Holder Cab 13

[Mark Towers]

Hi all,

In my 1943 Maintenance Manual for Canadian Military Pattern Vehicles, there is a picture of the layout for the Cab 13.

Above the drivers head, bolted to the cab roof is 2 x brackets for a Paralleloscope.

Can any one kindly explain what a Paralleloscope is ???

I have Googled it but to no avail

Your help is much appreciated.

Kind regards,

Mark Towers

[cletrac (RIP)]

From Wikipedia:
A prism paralleloscope is an item of kit used by artillery units as a gun aiming point when laying a gun for firing in the indirect fire mode. It is a long mirror aligned horizontally (to move in line with the guns dial sight) without parallax errors.

[Dave Mills]

A gun will have two parallelscopes in their stores, they are mounted to a tripod and are used as two of the aiming points for indirect fire. Can be often referred to as "Mirrors shaving 7 man" a night mare if they get caught in the cam net or bumped. To record a "P" scope as affectionatly referred to in the Arty is a very strict set of recording drills between the No3 Layer and the number 5 over seen by the Number 1. The angles are usual the first to be laid upon quickly followed by the No2 "P" scope and then the close and distant GAP (Gun aiming points).
Dave.

[motto]

I am not an artilleryman but as I understand the function of the paralleloscope or 7 man shaving mirror, it provides a reference that allows a true bearing to be maintained if the gun moves back under repeated firing as the spade digs in etc.
That's the 'parallel' part of the nomenclature, the tube can be kept parallel to the original bearing which cannot be done if simply referencing a fixed point. As Cletrac quotes, it is 'without parallax errors'.
Gun laying has always interested me and I would like to be corrected if I am wrong or fall short of a reasonable explanation.

David