Calibration and performance of the ISO Long-Wavelength Spectrometer (original) (raw)

The ISO Long-Wavelength Spectrometer

Astronomy and …, 1996

The Long-Wavelength Spectrometer (LWS) is one of two complementary spectrometers aboard the European Space Agency's Infrared Space Observatory 1 (ISO) . It operates over the wavelength range 43 196:9 m at either medium (about 150 to 200) or high (6800 to 9700) spectral resolving power. This Letter describes the instrument and its modes of operation; a companion paper describes its performance and calibration.

The photometric calibration of the ISO Short Wavelength Spectrometer

Astronomy & Astrophysics, 1996

We give an overview of the photometric calibration of the Short Wavelength Spectrometer (SWS) through the Performance Verification phase. The basic strategy for deriving absolute flux densities from detector output for the grating and Fabry-Perot sections of SWS is reviewed, and the results are demonstrated with 2.4 -45 m spectra of representative standards Dra, Lyr, and Cru. The effects of in-orbit changes in the relative spectral response function (RSRF) and ISO pointing are discussed. The systematic continuum flux level uncertainties (1 ) are within the pre-launch specification of 30%. Further improvements depend on characterization of the in-orbit RSRF, improved performance of ISO pointing, and new data processing techniques.

Observing with the ISO Short-Wavelength Spectrometer

Astronomy & Astrophysics, 1996

The Short-Wavelength Spectrometer (SWS) is one of the four instruments on-board ESA's Infrared Space Observatory (ISO), launched on November 17, 1995. The spectrometer covers the wavelength range of 2.38 to 45.2 m with a spectral resolution ranging from 1000 to 2000. By inserting Fabry-Perot filters the resolution can be enhanced by a factor 20 for the wavelength range from 11.4 to 44.5 m. An overview is given of the instrument, its in-orbit calibration, performance, observing modes and off-line processing software.

A long-wavelength spectrometer for the infrared space observatory (ISO)

Infrared Physics

A combination of Fabry P6rots and a grating monochromator working in a parallel beam has been designed as a possible long-wavelength spectrometer for the ISO. It is a very flexible instrument and is capable of working at a high sensitivity and a range of resolving powers in the FIR, up to 104. The principles of the instrument's design are discussed and a brief outline of its capabilities given.

UvA-DARE ( Digital Academic Repository ) Observing with the ISO short-wavelengthspectrometer

1996

The Short-Wavelength Spectrometer (SWS) is one of the four instruments on-board ESA’s Infrared Space Observatory (ISO), launched on November 17, 1995. The spectrometer covers the wavelength range of 2.38 to 45.2 m with a spectral resolution ranging from 1000 to 2000. By inserting Fabry-Perot filters the resolution can be enhanced by a factor 20 for the wavelength range from 11.4 to 44.5 m. An overview is given of the instrument, its in-orbit calibration, performance, observing modes and off-line processing software.

The INFRARED SPACE OBSERVATORY (ISO)

Advances in Space Research, 1993

The Infrared Space Observatory (ISO), a fully approved and funded project of ESA, will operate at wavelengths from 3-200 microns. The satellite essentially consists of a large cryostat containing about 2300 litres of superfluid helium to maintain the telescope (primary mirror diameter of 60 cm) and the scientific instruments at temperatures between 2K and 8K. A pointing accuracy of a few arc seconds is provided by a three-axis-stabilisation system. ISO's instrument complement consists of four instruments, namely: an imaging photo-polarimeter (3-200 microns), a camera (3-17 microns), a short wavelength spectrometer (3-45 microns) and a long wavelength spectrometer (45-180 microns). ISO's scheduled launch date is May 1993 and it will be operational for at least 18 months. In keeping with ISO's role as an observatory, two-thirds of its observing time will be made available to the general astronomical community via several CaUsfor Observing Proposals.

Calibration of the spectrometer aboard the INTEGRAL satellite

X-Ray and Gamma-Ray Telescopes and Instruments for Astronomy, 2003

SPI, the Spectrometer on board the ESA INTEGRAL satellite, to be launched in October 2002, will study the gammaray sky in the 20 keV to 8 MeV energy band with a spectral resolution of 2 keV for photons of 1 MeV, thanks to its 19 germanium detectors spanning an active area of 500 cm 2 . A coded mask imaging technique provides a 2° angular resolution. The 16° field of view is defined by an active BGO veto shield, furthermore used for background rejection. In April 2001 the flight model of SPI underwent a one-month calibration campaign at CEA in Bruyères le Châtel using low intensity radioactive sources and the CEA accelerator for homogeneity measurements and high intensity radioactive sources for imaging performance measurements. After integration of all scientific payloads (the spectrometer SPI, the imager IBIS and the monitors JEM-X and OMC) on the INTEGRAL satellite, a cross-calibration campaign has been performed at the ESA center in Noordwijk. A set of sources has been placed in the field of view of the different instruments in order to compare their performances and determine their mutual influence. Some of those sources had already been used in Bruyères during the SPI standalone test. For the lowest energy band calibration an X-ray generator has been used. We report on the scientific goals of this calibration activity, and present the measurements performed as well as some preliminary results.

Calibration of the AKARI Far-Infrared Imaging Fourier-Transform Spectrometer

Publications of the Astronomical Society of Japan, 2010

The Far-Infrared Surveyor (FIS) onboard the AKARI satellite has a spectroscopic capability provided by a Fourier transform spectrometer (FIS-FTS). FIS-FTS is the 1 first space-borne imaging FTS dedicated to far-infrared astronomical observations. We describe the calibration process of the FIS-FTS and discuss its accuracy and reliability. The calibration is based on the observational data of bright astronomical sources as well as two instrumental sources. We have compared the FIS-FTS spectra with the spectra obtained from the Long Wavelength Spectrometer (LWS) of the Infrared Space Observatory (ISO) having a similar spectral coverage. The present calibration method accurately reproduces the spectra of several solar system objects having a reliable spectral model. Under this condition the relative uncertainty of the calibration of the continuum is estimated to be ±15% for SW, ±10% for 70-85 cm −1 of LW, and ±20% for 60-70 cm −1 of LW; and the absolute uncertainty is estimated to be +35/ − 55% for SW, +35/ − 55% for 70-85 cm −1 of LW, and +40/ − 60% for 60-70 cm −1 of LW. These values are confirmed by comparison with theoretical models and previous observations by the ISO/LWS.

The contribution of IFSI (Istituto di Fisica dello Spazio Interplanetario) to the ISO Project

Il Nuovo Cimento C, 1990

We describe the participation of the <~Istituto di Fisica dello Spazio Interplanetario>> in the Infrared Space Observatory (IS()) Project. We contribute to the international consortium of Institutes to build the Long Wavelength Spectrometer (LWS): in particular we have responsability for the construction of the data processing unit, i.e. the on-board computer.