hm. the only picture of a 6A i could find is this - http://www.gothard.hu/gttak/archive-...images/016.jpg (main page is http://www.gothard.hu/gttak/archive-.../astrocams.php - listed is some scarce info and the year 1918)
unfortunately the picture is of very bad quality so the engraving can not be seen well. otherwise the lens looks exactly like yours and interestingly - it was also used for astro photography ! so your friend is not the only one who used a 6A for that purpose. i presume it was popular among astro photogs because of the big FL and fast speed.
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