Mirzoyan, R.; Garczarczyk, M.; Hose, J.; Paneque, D.
Referencia bibliográfica
Astroparticle Physics, Volume 27, Issue 6, p. 509-511.
Fecha de publicación:
7
2007
Revista
Número de citas
5
Número de citas referidas
5
Descripción
We have developed a method to measure the mirror reflectivity of
telescopes. While it is relatively easy to measure the local
reflectivity of the mirror material, it is not so straightforward to
measure the amount of light that it focuses in a spot of a given
diameter. Our method is based on the use of a CCD camera that is fixed
on the mirror dish structure and observes simultaneously part of the
telescope’s focal plane and the sky region around its optical
axis. A white diffuse reflecting disk of known reflectivity is fixed in
the telescopes focal plane. During a typical reflectivity measurement
the telescope is directed to a selected star. The CCD camera can see two
images of the selected star, one directly and another one as a spot
focused by the mirror on the white disk. The ratio of the reflected
starlight integrated by the CCD from the white disk to the directly
measured one provides a precise result of the product of (mirror area
× mirror reflectivity).