Tamaya and Cassens & Plath are indeed still making excellent sextants (I have a Tamaya Jupiter) and the Chinese-made Astra 3B is a fine instrument at a very reasonable price although the optics in the telesope don't match those of the German or Japanese units. Mechanically you can't fault them.
The other German manufacturer was C. Plath of Hamburg, a separate company to Cassens & Plath. For a number of years I owned and used a C. Plath Navistar Classic, one of their top models. A brief history of the C. Plath company follows (taken verbatim from the Nautical Antiques website operated by master mariner Joel Jacobs, from whom I bought my Tamaya Jupiter.)
quote:-
"C. PLATH COMPANY HISTORY: In brief, Carl Plath started manufacturing sextants, in addition to other nautical products, in Hamburg Germany in 1862 though the purchase of the David Filby instrument company though the company's origin dates back to 1837.
As a result WW II, C.Plath was dismantled completely by the occupation forces. Around 1950, various prohibitions were lifted, and C. Plath was allowed to begin production again of sextants and other nautical instruments. Also in 1949,C.Plath was offered a gyrocompass patent and in 1951 the first gyrocompass designed to this patent was presented to the public. C.Plath progressed from the role of instrument maker to that of a modern marine navigation equipment manufacturer. In the following years the product range was expanded by many more modern designs such as autopilots, speed logs, radio direction finders, etc.
In 1962 C.Plath was acquired by Litton Industries, a large American concern.The C.Plath North American Division was set up in 1978 in College Park near Washington. 1996 saw the introduction of the world's first fiber-optic solid-state gyrocompass by C.Plath. The first ever gyrocompass with no moving parts.
Sperry Marine was formed in 1997 with the combination of C.Plath, Decca Marine and Sperry Marine with more organizational changes yet to come. After 163 years, C.Plath changes its name to Sperry Marine in May 2000. In 2001 Sperry Marine becomes part of the Northrop Grumman Corporation.
In the 1990's Plath came out with a series of new sextant designs with overlapping designs and confusing names. They seemed to have lost their way. Shortly thereafter, C. Plath quit producing sextants. The parent company has completely liquidated everything including machinery, equipment and spare parts."
Unquote.