16 Sep 2020

In recent months, despite the impact of the pandemic crisis, major progress has been made in integrating WEAVE with the William Herschel Telescope (WHT).

On June 23, the new 6-lens, two-degree prime-focus corrector (PFC) arrived at the WHT. Photos of the transport of the PFC to the mountain, and of its installation at the WHT, can be seen here.

A small acquisition camera and a Shack-Hartmann camera have been mounted behind the PFC to assess the quality of the images it delivers on-sky. On September 11, ING celebrated WEAVE PFC first light, after images of Vega were obtained with the acquisition camera.

On August 31, the WEAVE spectrograph arrived at the WHT and was installed in the GHRIL Nasmyth enclosure, after a 4000 km journey by truck and boat from the NOVA premises in Dwingeloo, the Netherlands. Its arrival on La Palma and installation are documented in this photo sequence.

The new spectrograph is dual arm: a 5900-Å dichroic splits the light between the blue and red arms. Dispersion is effected by inserting one of three VPH gratings in the blue arm, and one of two in the red arm, giving three spectroscopic modes, one for low resolution and two for high resolution, for observing up to 960 celestial targets at a time.

Looking to the future, the fibre positioner with its full-fibre complement will soon complete tests in Oxford, for transport to La Palma in October. Delivery of WEAVE hardware to La Palma will be completed with the arrival of the detectors soon thereafter.

The lenses of the two-degree corrector were polished at KiwiStar in New Zealand, and co-mounted at SENER AEROESPACIAL (Spain). The spectrograph was built by NOVA (the Netherlands), and its lenses were polished by INAOE (Mexico), NOVA, and TNO (the Netherlands). The VPH gratings were made by KOSI (USA), and the spectrograph control system was built by INAF-OAPD (Italy) and the IAC (Spain).

[Image]

(A) The new WHT instrument rotator and optical corrector successfully installed at the prime focus of the WHT.

(B) Staff in front of the WEAVE spectrograph, after its arrival at the WHT.

(C) The 3-tonne WEAVE spectrograph being lifted to its new home in the clean-room environment of the WHT's GHRIL Nasmyth enclosure.

(D) Blue light reflecting off the red camera of the WEAVE spectrograph, after installation in the GHRIL enclosure at the WHT Nasmyth platform.