June 24, 2021

Solar and Space Physics UNIToV

Gruppo di Fisica Solare e Spaziale Università di Roma Tor Vergata

Solar and UV Station

Immag0119

The Solar and UV station of Physics Department was built in 1991. It works as educational tool for graduate students in astrophysical courses and it is used to test acquisition systems for professional solar telescopes.

Solar Station

The Solar Station has been working both for full-disk observations and for testing and prototyping new instrumentation. The CCD cameras for IPM (THEMIS telescope) and IBIS (DST-NSO telescope) were calibrated at this station.

An heliostat mounted on the roof of the Physics Department and the main mirror, makes the solar beam available on two horizontal optical benches. On the first bench, a beam-splitter divides the solar beam on two channels: blue and red. On the blue channel, a CaII K Lyot filter and a CMOS camera provide a full disk image of the Sun.

 

On the red channel, there is a custom telescope that provides full-disk H-alpha images. Other filter systems are available to obtain full-disk images of the Sun: the LUTIN Fabry-Pérot prototype and a K Magneto Optic Filter. The achievable spatial resolution of the images  is ~2 arcsec. A quadrant-photodiode allows the heliostat to track the Sun continuously and maintain the solar image steady on the scientific channels. The second optical bench has been added in 2013 and is equipped with an AO system demonstrator, a monochromator and various spectral lamp for spectral analysis.

Kimage1
Ca-K image of the Sun acquired at the solar station.

UV Station

Everyone is exposed to UV radiation from the sun. Emissions from the sun include light, heat and UV radiation. The UV region covers the wavelength range 100–400 nm and is divided into three bands:

UVA (315–400 nm)
UVB (280–315 nm)
UVC (100–280 nm)

As sunlight passes through the atmosphere, nearly all UVC and approximately 90% of UVB radiation are absorbed by ozone, water vapour, oxygen and carbon dioxide. UVA  radiation is less affected by the atmosphere.
We investigate UV radiation using the telescope reported in the picture. We analize radiation in two bands: the full UV band (200-400 nm) and the UVC band (220-280 nm). We also measure radiation in a wide band (300-1010 nm) that overlaps the visible region.

uv