The Westerbork radio telescope (WSRT) is currently being transformed into an efficient 21cm L-band survey facility by replacing the front-ends in 12 telescopes by Phased Array Feeds (PAFs). The new APERTIF system significantly increases the field of view and thereby the survey speed of the WSRT. This upgrade is expected to be completed by the end of 2016.

geographic longitude:	06° 36′ 15″
geographic latitude:	52° 55′ 01″
altitude above sea level:	16 m
diameter telescope:	14 telescopes of 25 m diameter on 3 km baseline (in tight array mode: single dish diameter equivalent = 96 meter)
minimum elevation:	0°

Available observing mode: single dish, local interferometry, Very Long Baseline Interferometry (VLBI).

Frequencies used currently:

Frequency band	Observing mode
250 – 460 MHz	single dish, local interferometry
310 – 390 MHz	single dish, local interferometry, VLBI
560 – 610 MHz	single dish, local interferometry, VLBI
700 – 1200 MHz	single dish, local interferometry
1150 – 1750 MHz	single dish, local interferometry, VLBI
2215 – 2375 MHz	single dish, local interferometry, VLBI
4770 – 5020 MHz	single dish, local interferometry, VLBI
8150 – 8650 MHz	single dish, local interferometry, VLBI

Research programs: galactic radio astronomy (spectral line and continuum), extra-galactic radio astronomy (spectral line and continuum), VLBI, geodetic VLBI, pulsars.