Resolution performance of the extra ultraviolet telescopes

Abstract

The Extreme Ultraviolet Telescopes (EUT) Operates at wavelengths between 100-1000 Å. As an important parameter of the telescope system, before the launch, angular resolution is necessary to be calibrated for testing the imaging performance of EUT. However, the difficulty and expense of fabricating optical testing systems capable of imaging the characteristic EUV wavelengths, has precluded in working wavelength resolution testing. This article taken a Ritchey–Chrétien normal incidence optical system as sample and resolution tests were carried out at visible wavelength. Based on this measurement, the angular resolution error budget at visible wavelength was calculated. At working wavelength, we added the squares of the pointing jitter error, the resolution focusing error and the scattering error, to the theoretical Rayleigh diffraction limit at the wavelength of operation, and then take the square root of this sum, an upper limit estimate of telescope’s resolution was obtained about 0.4705 arcsec. This result proved that the EUT worked at diffraction-limited level and the resolution performance has met the demand of design.