AURORA on MEGSAT 1: a photon counting observatory for the Earth UV night-sky background and Aurora emission

A low-mass, low-cost photon-counting scientific payload has been developed and launched on a commercial microsatellite in order to study the near-UV night-sky background emission with a telescope nicknamed “Notte” and the Aurora emission with “Alba”. AURORA, this is the name of the experiment, will determine, with the “Notte” channel, the overall night-side photon background in the 300–400 nm spectral range, together with a particular 2+N2 line (λc=337 nm). The “Alba” channel, on the other hand, will study the Aurora emissions in four different spectral bands (FWHM=8.4–9.6 nm) centered on: 367 nm (continuum evaluation), 391 nm (1−N+2), 535 nm (continuum evaluation), 560 nm (OI). The instrument has been launched on the 26 September, 2000 from the Baikonur cosmodrome on a modified SS18 Dnepr-1 “Satan” rocket. The satellite orbit is nearly circular (hapogee=648 km, e=0.0022), and the inclination of the orbital plane is 64.56°. An overview of the techniques adopted is given in this paper.