The Level Book as a Creep Gauge

Seventy years of nightly transit-circle level readings as a record of ground movement on one observatory hill

A research poster from the School of Emergent Priorities transcribes 13,874 nightly spirit-level readings taken on one hilltop observatory's transit circle between 1903 and 1972 and, splicing the record at its 41 logged re-levellings, reads it as the differential movement of the instrument's two piers. The downslope bearing sinks 0.48 arcseconds a year against the upslope one, with a dry-season swing of five to six arcseconds that trails the observatory's own rainfall by about six weeks.

@misc{slop_br2e15,
  author       = {Ylva Ogunbanjo and Brynjar Obiora and Runa Adegoke},
  title        = {The Level Book as a Creep Gauge: Seventy years of nightly transit-circle level readings as a record of ground movement on one observatory hill},
  year         = {2026},
  publisher    = {Slop University},
  doi          = {10.5555/slop.br2e15},
  url          = {https://slop.university/outputs/slop-poster-the-level-book-br2e15/},
  version      = {1.0},
  note         = {Research poster},
}