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Location of Virgo

by Eric Chassande-Mottin last modified 2015-12-10 10:04

This page gives the location of Virgo

The detector Virgo is located in the countryside of Cascina about few km south of the city of Pisa, Tuscany.

Using GPS, we have determined the nominal position of the mechanical center of the towers where Virgo's mirrors are mounted. The exact position of the mirrors may differ with respect to these reference positions by few millimeters. Below, we give those coordinates i.e., latitude, longitude, height [m] expressed in the reference frame IGM95 (WGS84 Italian official datum)

Beam splitter
  43° 37' 53''.0880 N 
  10° 30' 16''.1885 E  
  53.238 m
North end Mirror  43° 39' 24''.9479 N 
  10° 31' 00''.8264 E 
  53.069 m
West end Mirror  43° 38' 25''.4694 N 
  10° 28' 09''.7319 E 
  51.749 m

The azimuth of the North arm with respect to the geographic North is

19.432768° = 19° 25' 57".9650 (clockwise) or equivalently

340.567232°= 340° 34' 2''.0350 (anticlockwise)

The azimuth of the West arm with respect to the geographic North is

289.433085° = 289° 25' 59".10 (clockwise) or equivalently

70.566915°= 70° 34' 0''.90 (anticlockwise)

Location of the Virgo optical elements referred to the new reference system VRS (2012-2015)

Andrea Paoli

During the construction of Advanced Virgo (2012-2015) a new 3D local Cartesian system named VRS (Virgo Reference System)1 has been defined. VRS has the origin close to the BS mirror center, the Z-axis along the direction of the local gravity in the origin, the Y-axis parallel to the North Arm and the X axis completing a set of 3 clockwise axes.

Here we report the positions of the relevant optical elements of VIRGO referred to the new system. The VRS coordinates of the Virgo vertexes are:

x [m]

y [m]

z [m]

Beam Splitter




North End




West End




The VRS coordinates of the Virgo vertexes have been transformed in the ETRS (European Terrestrial Reference System)2:

X [m]

Y [m]

Z [m]

Beam Splitter




North End




West End




The same coordinates correspond to the following geographic coordinates:



h [m]

Beam Splitter

43° 37' 53''.1061 N

10° 30' 16''.2095 E

53.089 m

North End

43° 39' 24''.9464 N

10° 31' 00''.8387 E

52.899 m

West End

43° 38' 25''.4873 N

10° 28' 09''.7533 E

51.575 m

The azimuth of the geodetic curve through the Beam Splitter and the North End mirror , with respect to the geographic North, is:

                                                                      19.43297959° = 19° 25’ 58”.7265

The azimuth of the geodetic curve through the Beam Splitter and the West End mirror, with respect to the geographic North, is:

                                                                   289.43293666° = 289° 25’ 58”.5720.

1 The VRS was determined in collaboration with the University of Roma “La Sapienza” –(DICEA) and the University of Bologna (DICAM). Surveying was conducted through an integration of total station and GNSS measurements.

2 The transformation is done by an analytical approach . The ETRS is the geocentric reference frame recommended for geodata for Europe. It is the only geodetic datum to be used for mapping and surveying purposes in Europe. It plays the same role for Europe as NAD83 for North America.


GPS coordinates of the Virgo vertexes, VIR-065A-08 01 August 2008

EGO-REP-INF-111 Issue 1 18/10/2005