download report - Sapienza

Scientific Report 2007-2009
Laboratories and Facilities of the Department of Physics
L25. Solar Radiometry Observatory
The research activities of the Meteorology group (GMET) intend to assess the influence of the decrease of ozone and its
effect on UV radiation variability. The GMET equipment consists in a Brewer spectrophotometer MKIV n.067, installed
in 1992 on the roof of the building of the Department of Physics in the University Campus. Direct sun measurements at 5
wavelengths in the UVB and VIS regions are carried out to retrieve total O 3 and NO 2 amounts, respectively.
Measurements of solar UV spectral irradiances in the
spectral range from 290 to 325 nm, with a stepwidth
of 0.5 nm, have been carried out since 1992. This long
UV time series is necessary to assess the influence on
ecosystems and on human health. In addition, erythemal
dose rates have been obtained by the broadband UV
radiometer (model YES UVB-1) in operation since
2000. The YES radiometer has a spectral response
similar to that of skin erythema and values of erythemal
dose rates are obtained using a calibration matrix
as a function of solar zenith angle and total ozone
amounts from Brewer spectrophotometer. Ambient UV
radiation is also used in the quantification of human
UV exposure by means of polysulphone dosimetry,
this another research activity. Ancillary meteorological
measurements of air temperature, relative humidity,
and wind, are also available to characterize the UV Figure 1: Solar Radiometry Observatory (University Campus).
field.
http://www.phys.uniroma1.it/gr/gmet/index.html
Related research activities: G2.
L26. The Vallinfreda astronomical Station
The SCAE group has an observing facility near Vallinfreda, (a small town 50 km ENE of Rome), located at 850 m above
the sea level with a rather low sky brightness (V=20.5 mag/arcsec2). Geographical coordinates are Long. 12o 58’ 52” East,
Lat. +42o 06’ 01”. Routine observations at Vallinfreda started by the end of Summer 1995.
The telescope is a Newtonian 50 cm f/4.5, built by GAMBATO, powered by an FS2 system, housed in a sliding-roof
building (see fig. 1). A standard 12m-long container, provided by the italian Protezione Civile, gives logistical support.
The focal plane instrument is an Apogee ALTA
AP47 CCD camera and a TrueTech filter wheel
with standard BVRI Johnson-Cousins filters, provided
by Astrodon-Schuler. Electric focuser is by
MicroFocuser. Guiding is made with a 15 cm f/12
refractor telescope manifactured by ZEN and a
StarLight Xpress MX916 camera.
All telescope operations (telescope pointing, filter
wheel movements, image acquisition and guiding)
are controlled by a PC with Windows XP operating
system. The limiting magnitude, with a
S/N ratio about 0.1 is 17.5 in the R band.
The telescope is mainly dedicated to monitoring
of BL Lacertae objects, a subclass of Quasars with
strong Radio and Gamma Rays emission, with special
care for simultaneous observations with spaceborn
instruments (Beppo-SAX, SWIFT, INTEGRAL, AGILE, FermiGST).
Figure 2: The Vallinfreda telescope in its sliding-roof building.
About 25 papers on refereed international journals have been made using (also) data obtained with the Vallinfreda
telescope.
http://astrowww.phys.uniroma1.it/nesci/vallin.html
Related research activities: A9.
Sapienza Università di Roma 194 Dipartimento di Fisica