The Cherenkov Telescope Array (CTA) is a new observatory for very high-energy (VHE) gamma rays. CTA has ambitions science goals, for which it is necessary to achieve full-sky coverage, to improve the sensitivity by about an order of magnitude, to span about four decades of energy, from a few tens of GeV to above 100 TeV with enhanced angular and energy resolutions over existing VHE gamma-ray observatories. An international collaboration has formed with more than 1000 members from 27 countries in Europe, Asia, Africa and North and South America. In 2010 the CTA Consortium completed a Design Study and started a three-year Preparatory Phase which leads to production readiness of CTA in 2014. In this paper we introduce the science goals and the concept of CTA, and provide an overview of the project. ?? 2013 Elsevier B.V. All rights reserved

No abstract

No abstract

Herschel is an ESA spaceborne far infrared observatory, to be launched late 2008. It's key science objectives emphasize specifically the formation of stars and Galaxies. The focal plane of the 3.5m diameter telescope is shared by three instruments located in the cryostat: PACS (imaging photometer and integral field line spectrometer, operating from 35µm to 205µm wavelength); SPIRE (imaging photometer and Mach-Zender interferometer, operating from 194µm to 572µm wavelength); and HIFI (heterodyne detector, from 157 to 625µm wavelength). Infrared straylight rejection is one of the key performances of the Herschel observatory. In this paper, we present the straylight requirements, some specific design issues, the estimated performances and test results.

No abstract