prismatic astrolabe attachment
Date: circa 1960
Inventory Number: 2003-1-0138
Classification: Theodolite
Dimensions:attachment: 14.3 × 9.6 × 12.4 cm (5 5/8 × 3 3/4 × 4 7/8 in.)
case: 18.5 × 20 × 15.5 cm (7 5/16 × 7 7/8 × 6 1/8 in.)
Accessories: dust cover; carrying case
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.