CRIRES and VISIR, ESO's latest tools for infrared studies of PNe beyond the Milky Way

H.U. Käufl
European Southern Observatory, Karl-Schwarzschild-Str. 2, D-85748 Garching, Germany


CRIRES and VISIR are the last instruments of the first generation of VLT instrumentation. CRIRES is a cryogenic pre-dispersed long-slit (~40'') spectrograph with a nominal resolution λ/Δλ~105 (i.e. ~3 km/s). It covers the 1-5.5μm wavelength regime. In combination with adaptive optics CRIRES has a spatial resolution and a respective slit size of 0.2 arcsec. However in the absence of guide stars, or if the maximum spectral resolution is not mandatory, the slit can be opened and adjusted, either to the seeing or to the astrophysical requirements. The CRIRES focal plane is equipped with a mosaic of four 10242 pix InSb arrays. This will allow for a quasi-instantaneous access to 2% of the spectrum in one exposure while Nyquist sampling.

VISIR is a multi-mode instrument for imaging and spectroscopy between 8 and 24μm. The camera has a field of view of typically 30×30 acsec2. It is fully difraction limited, i.e. at λ~10 μm the spatial resolution is ~300 mas. In spectrosocpy mode VISIR offers three ranges of spectral resolution up to a typical resolution λ/Δλ~ 3×104 (i.e. ~10 km/s). Both arms are equipped with one 2562 pix As:Si BIB array each.

VISIR is presently being commissioned on VLT-UT3 while CRIRES shall arrive on Paranal in mid 2005.

Both instruments, in combination with the VLT 8m UTs will allow for infrared studies of Planetary Nebulae way beyond the Magellanic Clouds.