Heliometer
“Dollond’s divided object-glass heliometer of the third type. A is the end of the reflecting telescope, upon which the adapter B is fitted. B carries a wheel (not seen in the figure) formed of a ring racked at the outer edge, and fixed to the brass plate CC, so that the pinion moved by the handle D may turn it into any position. Two plates F, G, with the attached semi-lenses, move in slides fixed to the plate CC, —simultaneous motion, in contrary directions, being communicated to them by turning the handle E, which drives a concealed pinion that works in the two racks seen in the highest part of the figure.” —The Encyclopedia Britannica, 1903
Galleries
AstronomySource
The Encyclopedia Britannica, New Warner Edition (New York, NY: The Werner Company, 1893)
Downloads
1238×2400, 378.6 KiB
528×1024, 52.7 KiB
330×640, 28.3 KiB
165×320, 10.6 KiB