NavList:

   

Reply

frankreed@HistoricalAtlas.net wrote:
> I was surprised that nobody else has answered this question. I think your
> analysis here is correct. That little "dot" does indicate the zero, and the
> individual marks are tenths of a minute of arc. In theory, you could use the
> central mark as zero (which would require a different index correction), but
> then you would have to count the upper markings as negative tenths, which
> would become annoying. The top line is the proper zero.
>
>  -FER
Frank and Jim,
Thanks for reinforcing what I thought was the correct zero and scale but
I wasn't sure since it seemed more "natural" to use the middle mark.  I
must say the dot at the end of the top mark is rather small on my
instrument and hard to distinguish, at least at my age and with my
vision.  Negative tenths would be more than annoying to me and it seems
there would be more likelihood of an error creeping in if one were to
try to use it that way.
--Scott

--~--~---------~--~----~------------~-------~--~----~
To post to this group, send email to NavList@fer3.com
To , send email to NavList-@fer3.com
-~----------~----~----~----~------~----~------~--~---

   

Reply