Surveyor's eye candy...
Tell us more - date? History of owners/area used?
On close inspection of the photos I now see it is Gurley.
That's an oldie I'd love to have.
Trying to imagine having to operate that precisely as you could get. wow.
Made by Gurley circa 1883 I believe. See the description in the Gurley catalogue page 28.
So perhaps 140 years ago in April.
@rj-schneider You definitely need good eyesight.
@rj-schneider You definitely need good eyesight.
I think it was standard practice to carry a small magnifying lens.
Trying to imagine having to operate that precisely as you could get. wow.
I seem to remember reading careful work under good conditions could get 5 minute repeatability.
The declination arm pivots right around on its axis, and has a pointer that indicates the hour on the hour angle arc. So you see it has two lenses and two silvered cross hatch targets, one below and one above. This is for use in either hemisphere of the world.
Thanks to Dale, Russ, and Dave Ingram for helping with info and procuring the compass and tripod.
Dale says that this instrument came from a collection in Northern California, and Dave says the declination arm rotates 360 to allow for either positive or negative declination of the sun as the seasons change.