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Inverting Scope
From: Bruce Stark
Date: 2004 Oct 9, 21:25 EDT
From: Bruce Stark
Date: 2004 Oct 9, 21:25 EDT
At 22:10 on the twenty-second of last month Fred wrote:
"Bruce recently acquired an inverting telescope; perhaps he'll jump in here if he's
back from his trip to compare it's virtues to those of the modern prism
monocular."
Although I wasn't back then, I am now, and am beginning to skim a month's worth of postings. My SNO-T, (or SNO-T) sextant is stamped 1974. Optics of both scopes are excellent. The inverting scope, interestingly, has at least as much light-gathering ability as a 7X35 Tamaya monocular. That in spite of having a smaller objective lens. Perhaps it's that the light passes through fewer glass surfaces.
The star scope is far better at gathering light than the other two, of course.
The wire reticule is fixed at the back of the objective tube, just as Alex describes it. The wires are nearly 2 degrees apart in the field. Two vertical, two horizontal. Why the horizontal ones, I don't know. But they do make it easy to measure the angular distance between wires.
If all you want to do is measure altitudes above the sea horizon, don't bother with an inverting scope. Same if you only measure short lunar distances. But if you want to accurately measure the longer lunar distances, or do accurate work with an artificial horizon, you'll find the inverting scope invaluable. Just don't let the thing drive you crazy at first. With experience you'll learn to like it a lot.
My guess is, a right-side-up scope with a reticule would be far more expensive. That is, one with comparable optics.
Bruce
"Bruce recently acquired an inverting telescope; perhaps he'll jump in here if he's
back from his trip to compare it's virtues to those of the modern prism
monocular."
Although I wasn't back then, I am now, and am beginning to skim a month's worth of postings. My SNO-T, (or SNO-T) sextant is stamped 1974. Optics of both scopes are excellent. The inverting scope, interestingly, has at least as much light-gathering ability as a 7X35 Tamaya monocular. That in spite of having a smaller objective lens. Perhaps it's that the light passes through fewer glass surfaces.
The star scope is far better at gathering light than the other two, of course.
The wire reticule is fixed at the back of the objective tube, just as Alex describes it. The wires are nearly 2 degrees apart in the field. Two vertical, two horizontal. Why the horizontal ones, I don't know. But they do make it easy to measure the angular distance between wires.
If all you want to do is measure altitudes above the sea horizon, don't bother with an inverting scope. Same if you only measure short lunar distances. But if you want to accurately measure the longer lunar distances, or do accurate work with an artificial horizon, you'll find the inverting scope invaluable. Just don't let the thing drive you crazy at first. With experience you'll learn to like it a lot.
My guess is, a right-side-up scope with a reticule would be far more expensive. That is, one with comparable optics.
Bruce
