Greetings, fellow dialists,
Tom Kreyche wrote:
"With my Wild Heerbrugg T3000 Digital Theodolite equiped with a
Roelofs Solar Prism I can achieve a few seconds accuracy for solar
observations by taking a great deal of care with the sophisticated
leveling system, assuming the base is stable, the temperature doesn't
change, there is no wind and you don't touch the instrument. No doubt an
experienced surveyor with astronomical observation experience can do
better, or perhaps an experienced navigator with a good sextant."
In fact any run-of-the-mill astro-navigator with a merely passable
sextant could at least manage an accuracy of a minute of arc, or four
seconds of time. Accuracy down to a tenth of a minute is quite possible.
Would that be partly because sextant observations use the edge (limb) of
the sun and not the less precise whole disc? Of course, the sea horizon,
with a small correction, gives you a perfect level, too.
For a really accurate dial could the east or west limb of the sun be
projected and utilised?
Frank 55N 1W
---------------------------------------------------
https://lists.uni-koeln.de/mailman/listinfo/sundial
