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Hello, Marc!

I am attaching SNO-T manual in English (pdf file). But take into account that earlier SNO-T instruments had higher accuracy standards than the late ones (therefore technical values in different manuals may vary). For example, earlier models had instrument accuracy within 6 arcseconds, max backlash also 6 arcseconds; correction max value 30 arcseconds. Contrary my SNO-T from 1988 has these values accordingly 12" , 20" and 66" (see attached photoes of my SNO-T original manual).

 If you are interested more deeply in construction of this sextant model, I recomend ebook by Bill Morris “THE SNO-T SEXTANT (with notes on the Freiberger Drum sextant) Construction, repair and maintenance. “ This is a great book which helped me to fully disassemble and then reassemble my SNO-T.

I don’t agree only with one thing, he mentions in his book (and also in his sextantbook.com), namely

“In most examples of the SNO-T, the horizon shades are incorrectly assembled. See https://sextantbook.com/2013/10/ for details.)”

Mr. Morris reccomends to flip shades thus improving their performance with Galilean scope . I experemented with this. But I did not like this design, because the shades in their working position can’t be simply rotated fully to end position (they must always be slightly adjusted before end position). In original design shades are designed to be used only with astronomical telescope, not with Galilean scope (night scope).  But anyway his book is brilliant.

Modris Fersters  

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