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 Scientific Instruments are collected in the "Requirements for Scientific Instruments on the VLT Unit Telescopes" (VLT-SPE-ESO-10000-2723 issue 1 dated 18.03.2005). Although 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), no corresponding document exists for the UT2 Cassegrain focus yet: 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.