INTRODUCTION

ISOCAM is the instrument on ISO designed to map selected areas of the sky in the spectral region from 2.5 to 17 m at various spatial and spectral resolutions. Polarization mapping is also possible.

With ISOCAM it will be possible to study spectral features at wavelengths inaccessible from ground; one example is imaging of water vapor emission in the circumstellar environment. The morphology of spatial structures at a scale of a few arcmin can be investigated in broad and narrow band filters or with spectral imaging, with a spatial resoluion of a few arcsec.

The spatial resolution is limited by the diffraction at longer wavelengths, and by the pointing of the satellite at shorter wavelengths. For a 60 cm diameter telescope the diameter, in arcsec, of the Airy disc /D = (micron)/3, or 2.4/D = 0.8(micron) for the first dark ring.

A wide range of astrophysical problems can be tackled with ISOCAM. Examples of current interest include:

• solar system studies: structure of zodiacal bands and cometary trails, spectral maps of comets,
• interstellar matter and star formation: nature of 12 m emission of large molecules or grains, grain formation or destruction, interaction between supernovae and the interstellar medium,
• stars and circumstellar material: observation of faint infrared young stellar objects, mapping of outer regions of planetary nebulae,
• galaxies: star forming regions, characteristics of the various galaxy types in the ISOCAM wavelength range,
• cosmology: deep surveys for studies of galaxy evolution and brown dwarfs, study of faint galactic nuclei and of clusters of galaxies.

This manual contains a description of the instrument such that observers understand its capabilities and the constraints, to be able to plan time efficient observations and to calculate observing times.