Four years of optical turbulence monitoring at the Cerro Tololo Inter-American Observatory (CTIO)

TL;DR

This study presents four years of optical turbulence data at Cerro Tololo, compares it with MASS-DIMM measurements, identifies dome-induced turbulence effects, and proposes corrections to improve turbulence characterization.

Contribution

It provides a long-term turbulence dataset, analyzes seasonal and nightly patterns, and addresses dome effects impacting DIMM measurements at Cerro Tololo.

Findings

Dome-induced turbulence affects DIMM measurements under northerly winds.

A correction method for dome effects was developed and applied.

Turbulence conditions show seasonal and nocturnal variations.

Abstract

The optical turbulence conditions as measured between 2004 until end of 2008 above Cerro Tololo, their seasonal as well as nocturnal behavior are presented. A comparison with the MASS-DIMM system of the Thirty Meter Telescope site testing was conducted and identifies an artificially increased seeing component in the data collected by the CTIO DIMM system under northerly winds. Evidence is shown that this increased turbulence is caused by the telescope dome. A correction for this effect is attempted and applied to the CTIO DIMM data. The MASS data of this comparison campaign allow to set constraints on the general assumption of uniform turbulent layers above a site.