The Visitor Focus has been reserved to permit innovative observations by teams using stand-alone instruments. The Visitor Instrument teams should in particular be able to react quickly to new scientific and/or technical opportunities. Visitor Instruments are therefore free from a substantial fraction of the requirements imposed on VLT facility instruments.

The requirements of the VLT towards (facility) Scientific Instruments are collected in the "Common Requirements for VLT instruments". Most of the mentioned applicable documents are collected in this file. An updated version of the Common Interface Control Document between VLT Scientific Instrument and the VLT Observatory is being prepared.

An older version of this document was tailored to Visitor Instruments for the UT3 Nasmyth Focus in "Requirements for Visitor Instruments on the VLT UT3 Visitor Focus" (VLT-SPE-ESO-10000-3912 issue 1 dated 27.09.2007), with similar requirements  for other foci. This document must be updated. Hence, it is strongly recommended that a Visitor Instrument team double-check with ESO all necessary details before designing critical items.

We make available here as separate pdf files with higher resolution than in the document appendix the applicable interface drawings:

A data sheet for the portable LN2 storage tanks (type XRP 120) used on Paranal is available here.

A gallery of pictures showing the Nasmyth focus is also available.