prismatic astrolabe attachment
Date: circa 1963
Inventory Number: 2003-1-0137
Classification: Theodolite
Dimensions:object: 11.3 × 8.8 × 10 cm (4 7/16 × 3 7/16 × 3 15/16 in.)
case: 13.6 × 17 × 14.4 cm (5 3/8 × 6 11/16 × 5 11/16 in.)
Accessories: carrying case; dust cap; eyepiece
Description:
Instrument made to fit on a 70 mm telescope. Artificial horizon (most likely mercury) and very accurate beam splitting prism for astronomical delineations of time or position. It has a circular bubble level attached on the side of the artificial horizon. The prism is mounted on three leveling spring screws. It is stored in a carrying case when not in use.
The mercury pool is an extremely shallow concave copper surface which provides a "beach" for damping vibration.