I Don't Get It, A 6 " Theodolite Should Be Read To 2" Or 3"
T-16 I remember from the late 70s had a direct reading scale. It felt more and reminded me of an enclosed building transit.
The T-1A had a micrometer dialin scale that read to 5sec. It was typical upper and lower motions that was well built and was capable of tight closing traverse.
It looked much the same as the scales on a Sokkia SMDE3 except smaller.
The PC would only write down nearest 5sec no matter what I read out on the T-16.
The Sokkia SMDE3 is mine and myself and others have recorded angles down to 1sec with very good results.
I set my electronic guns to give readings to 1sec.
I Don't Get It, A 6 " Theodolite Should Be Read To 2" Or 3"
> T16 - 1 minute theodolite.
> T1 - 6" theodolite.
> T1A - 20" theodolite.
> T2 - 1 or 2?
The Wild T16 had a 79mm dia. horizontal circle, slightly smaller than the 85mm circle in the Zeiss Th43. In the case of the Zeiss, which I used extensively once upon a time, it wasn't a trick at all to read the scale by estimation to 6", with angles taken as the mean of two faces having a standard error of about 4". There were plenty of surveyors who read it as if it were just a 1-minute transit, but they were throwing the seconds fraction away.
I Don't Get It, A 6 " Theodolite Should Be Read To 2" Or 3"
Turns out I have one of the new style T1's from 1978. The micrometer is actually a sequence of minutes and every six seconds (as follows), but does not have any lines to match against the pointer.
25'06"
25'12"
25'18"
25'24"
25'30"
etc etc. from 00'00" to 60'00"
The micrometer actually as all the digits on it.
Looking at it I can see how you could try to split it into 3 second increments, but the bottom line is the T1 is a 6 second gun.
I Don't Get It, A 6 " Theodolite Should Be Read To 2" Or 3"
Per the T-1 specs.
"Fully numbered circles and micrometer read direct to 6", with estimation to 3"!"
As I said before.
Paul in PA