NavList:

Hi Jim

I have zilch knowledge of marine navigation but as this was the origin of the aeronautical very keen to have experience in all aspects.

I have no experience of marine sextant and live 100 km inland Australia, 3000 ft up where a natural sea level horizon is missing – somewhat. My wife bought me a marine sextant for Xmas after I decided I needed to regain celestial navigation skill.

It is a Davis Mk 25 plastic – probably not as robust as a ship’s brass ‘real one’ – but one of those was just a bit too expensive.

I then visited the coast – East coast after midday – to practice with ‘The Sun’ – my 1^st mistake and only needed a little thought – the sun was now West and obviously no natural horizon that way.  So I just practiced and got use to the marine sextant horizon  – and have since purchased a Davis false horizon – which works well but is messy and in the hot sun steams up or shimmers if you leave a glass cover off to prevent steaming up.

So I decided to get an aeronautical sextant to enable day/night shots – I did see Kollsman’s for sale but none in pristine  condition – remembering they are sensitive instruments and dirty worn old lens and gadget prone to corrosion would render them useless.

Then Bob S contacted me as I saw he was selling the B & L A-8A & A-12A aeronautical – these are fully reconditioned and aligned – I was going to buy the A-12A (historically the type used by “Dutch” Van Kirk on the Enola Gay) – though typically this was more of a training sextant and the general use one was the A-8A.

My first sextant was an astrodome RAF Mk IX or X – a robust and good sextant – however none were available – so I decided to get an A-8A bubble sextant after talking with Bob S.

It duly arrived in pristine condition – no bubble – but a phone call from Bob S quickly had that working and the sextant is wonderful and a joy.

And a plus plus with it I was not aware of when I bought it – and hence why I am now recommending you buy this model (notwithstanding Bob is a fully qualified instrument maker) – but the A-8A is one of only a few aeronautical sextants that can be BOTH a Bubble sextant or a real horizon sextant  - yep it is BOTH!!!

Unlike the Mk IX, X RAF and the Kollsman the average is manual – but it averages 8 shots – a bit more mechanical than the true wind up average but perfectly workable.

I just haven’t had time to get up to speed but it sits lovingly on my desk.

Regards Howard

From: NavList@fer3.com <NavList@fer3.com> On Behalf Of Jim Rives
Sent: Saturday, 2 April 2022 13:15
To: Howard George <HHG@raptorbusinessservices.com.au>
Subject: [NavList] Re: Kollsman Periscopic Sextant for sale