If, like me you wondered how the bubble sextant was checked and calibrated then this book will help you to understand how the instruments were checked at Station level. Calibration was another matter altogether and the booklet makes clear that out of cal. instruments were to be returned to a M.U. for adjustment. This booklet gives a clear drawing of the optical setup and there are a couple of photos showing how the sextant was set up on the Portable Collimator and the procedure to be adopted when checking one. I found it very interesting, sufficient to nudge me into trying to make one for my own use.  A5, 8 pages black and white
See https://g4osj.co.uk/Text/Catalogue.html for more info.

Postage (UK) £2.00

Please note that unless specifically stated otherwise in my listing all printed material is a copy. NOT original material.

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Some feedback for this item:-

Arrivato tutto ok. Grazie.  Will help me to service my type ix sextant.Thanks. As described. Arrived promptly.