Ferris State's T4 was manufactured in 1956. Most of the T4 that were sent to the US were purchased by the Army. Our instrument was originally owned by the National Oceanic and Atmospheric Administration. The Ferris State surveying program acquired the T4 in 1976. WILD only produced 439 T4 theodolites. The model was in production from 1941 to 1981.
Josh Sanders and Taylor VanDyke - 2024
Direct circle readings:
0.1 arc second horizontally
0.2 arc second vertically
The T4 has a broken telescope which allows for comfortable astronomic observations when the telescope needs to point towards zenith. The telescope provides 65x magnification.
Jens Otto Rick explaining the T4 to students.
Last protocol of two circles tests provided by Jürg Dedual of the Virtual Archive of Wild Heerbrugg of an instrument with a serial number three after ours!
Horizontal circle and hanging vial from a T4 provided by Jürg Dedual of the Virtual Archive of Wild Heerbrugg.
Photo Credit: WILD Heerbrugg
Photo Credit: NOAA
Photo taken in 1970 of Coast Survey field party member using T4.
NOAA:
https://celebrating200years.noaa.gov/theodolites/wild.html
Virtual Archive of WILD Heerbrugg:
https://www.wild-heerbrugg.shop/index.php?cPath=1_3_5_25_63
T4 usage in Australia:
https://www.xnatmap.org/adnm/ops/manuals/T4/WILD_T4_AUST.htm
