NavList:

The Astra is a GLH130-40 (or a GLH130-20 in the case of the Astra Professional). The "CP Sailing" sextant sold by Cassens & Plath to cover the mid-tier market also is nothing other than a GLH130-40. I wouldn't expect any distinctive differences, apart from the sticker at the left end of the arc and slight changes over the years, because these are essentially the same instruments. The only feature that distinguishes Celestaire's Astras from the generic GLH130-40/20 is the replacement of the round index mirror with a square one, intended to facilitate easier observations of bodies at higher angles.

I have always wondered about Celestaire's warning about Chinese knockoffs. Sextants, in our time and age, don't strike me as items sold in a volume that would make cloning them profitable.Chances are that the Chinese produced these sextants for their merchant marine and navy well before Celestaire teamed up with them in a joint venture, that they still do (though in a lower volume), and that most offers popping up on alibaba & Co are genuine merchandise. While I wouldn't want to buy through alibaba & Co for a number of reasons, Celestaire would clearly have an incentive for discouraging people from buying their main product directly from China at half the price. By the way, given the many satisfied Astra users, I'd be equally sceptical of a French supplier's opposite claim (http://digipoche.free.fr/voirarticle.php3?NUMART=4) that even genuine Astra sextants are in "overall finish and level of quality far below Western standards," requiring extensive fine-tuning to rectify their "original defects," resulting in almost a doubling of their price (http://digipoche.free.fr/listearticle.php3?TYPEART=Sextants).

If you are satisfied with your sextant's precision, as you seem to be, I really don't see any need to give this any further thought. If you wanted to double check, you could take a few sights of angular distances between fixed stars to confirm accuracy, to give you extra peace of mind. And if you are a stickler for precision, you could send your instrument to Freiberger in Germany (www.fpm.de), probably the oldest-school of the old-school sextant makers still extant and the only one routinely measuring and certifying instrument error values, down to the second (to my knowledge, they certify and service sextants of other brands as well as their own). But I doubt that this would be of any practical consequence.