ULTRASPEC on the 2.4m TNT
During 2011-2012, we converted ULTRASPEC into a brand new
imaging instrument. We kept the original EMCCD in its
cryostat, but added an opto-mechanical chassis housing custom-made
re-imaging optics and an updated data acquisition system based on the
latest version of the ULTRACAM system. The new ULTRASPEC saw first
light at the 2.4m TNT on 2013 November 5, and is now permanently
mounted on this telescope for at least the next 2 years. Just to
re-emphasize, ULTRASPEC is now a high-speed imager - essentially a
one-armed ULTRACAM - and hence does not currently have any
spectroscopic capability, although it would be trivial to convert it
back for spectroscopic use on EFOCS2 on the NTT if we wanted
to.
ULTRASPEC on the TNT provides imaging photometry over a field of view
of 7.7'x7.7' with a pixel scale of 0.45 "/pixel. A selection of 14
different broad-band and narrow-band filters can be accommodated in
its 6-position filter wheel, covering the wavelength range 300-1000
nm. Zero readout noise is available via the avalanche output, or 2.5
e- readout noise via the normal output. The detector is
liquid-nitrogen-cooled to 160 K, providing dark current of less than
10 e-/pixel/hr. The maximum frame rate using small, binned
windows in drift mode is approximately 200 Hz.
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