alsopb@vance.net wrote:
> Jonathan,
>
> Question:
>
> Just for curiousity, how well do you think you can plumb a transit
> before using it to plumb a tower?
>
> I ask because of some background in celestial navigation. Even with the
> sextant and bubble "horizon" combo in a vice, one was luckly to be
> within 0.5 degrees of vertical. A little trig yields up to 6" of error
> at the top of the 100' tower for the transit being off level by 3
> degrees.
>
> Of course we were trying to get the elevation of a star or the sun
> within 1 minute accuracy or better so what you might call level for a
> transit would be unsatisfactory for a sextant.
>
> 73 de Brian/K3KO
> Vance Net Inc
> End Of Message
Hi Brian,
My transit is an old Leitz, with plenty of wear marks. Although it came
without instructions, I found a copy of the calibration instructions. I have
not yet done a full calibration on it (it looks like about a half hour of
thoughtful work) but by comparing both sides of the arc, and by checking
both sides of the tower against each other from points 180 degrees apart, it
appears to be accurate to about a quarter inch (1/10 of a tower leg) over
100'.
I'm not sure how that corresponds to arc.
Aloha,
Jonathan KH6X
kalepa@maui.net
--
FAQ on WWW: http://www.contesting.com/towertalkfaq.html
Submissions: towertalk@contesting.com
Administrative requests: towertalk-REQUEST@contesting.com
Problems: owner-towertalk@contesting.com
Search: http://www.contesting.com/km9p/search.htm
|