7 SETI Program at the Medicina INAF Radioastronomy …
67
Table 7.1 September 20,
2018, SETI observation
schedule and report of
completed operations
Exoplanet
Number of observations Observations length
Gliese 163 c 2
30 and 50
K2-18 b
1
2 h 10
Kepler-174 d None
Luyten b
None
Ross 128 b
1
35
Trappist-1 d None
Wolf 1061 c 1
50
reduction of others (see Table 7.1). Observations were carried out with a radio
bandwidth centered at 1.42 GHz frequency (21 cm wavelength) named Hydrogen
line.
Another problem related to these observations was the maintenance works to
the Medicina RT-32 receivers room that was carried out in that month and reduced
out work bandwidth to 20 MHz. So, based on all the problems faced, we decided
to reduce the bandwidth to 10 MHz and to use both the first and the second pilot
project spectrometers connecting them to the same signal with the secondary goal
of comparing their results in the postprocessing phase [38, 39].
The spectrometer data processing was set to the standard Serendip IV processing
(see Fig. 7.13). It is composed by a sequence of operations: FFT (a), normalization
(d) composed by boxcar computation, and subtraction (b) to remove the filter shape
followed by moving average (c) to compute the threshold, as spectrum local mean
value multiplicated by a programmable factor), and final selection of the spectrum
rows with amplitude over the threshold. The first pilot project spectrometer was set
up at 12.5 MHz bandwidth with a 100 Hz resolution obtaining a spectra rate of about
10 spectra per second. The second pilot project spectrometer was set up at 10 MHz
bandwidth with a 1 Hz resolution obtaining a spectrum every 5 min.
Observation results were saved as in two file format:
• SIV—the standard output file format of Sentinel IV spectrometer suitable for the
use of the old Sentinel IV post-processing software,
• RAW—the standard new spectrometers line file format for general SETI observations (a more straightforward and improved version of SIV) (see Fig. 7.14).
The comparison of the observation results, produced by both spectrometers, proved
a precise agreement between them (net of the technical parameters of the two
spectrometers such as spectra resolution and rate).
Post-processing of observations results showed no results in ETI signal detection
[40].
67
Table 7.1 September 20,
2018, SETI observation
schedule and report of
completed operations
Exoplanet
Number of observations Observations length
Gliese 163 c 2
30 and 50
K2-18 b
1
2 h 10
Kepler-174 d None
Luyten b
None
Ross 128 b
1
35
Trappist-1 d None
Wolf 1061 c 1
50
reduction of others (see Table 7.1). Observations were carried out with a radio
bandwidth centered at 1.42 GHz frequency (21 cm wavelength) named Hydrogen
line.
Another problem related to these observations was the maintenance works to
the Medicina RT-32 receivers room that was carried out in that month and reduced
out work bandwidth to 20 MHz. So, based on all the problems faced, we decided
to reduce the bandwidth to 10 MHz and to use both the first and the second pilot
project spectrometers connecting them to the same signal with the secondary goal
of comparing their results in the postprocessing phase [38, 39].
The spectrometer data processing was set to the standard Serendip IV processing
(see Fig. 7.13). It is composed by a sequence of operations: FFT (a), normalization
(d) composed by boxcar computation, and subtraction (b) to remove the filter shape
followed by moving average (c) to compute the threshold, as spectrum local mean
value multiplicated by a programmable factor), and final selection of the spectrum
rows with amplitude over the threshold. The first pilot project spectrometer was set
up at 12.5 MHz bandwidth with a 100 Hz resolution obtaining a spectra rate of about
10 spectra per second. The second pilot project spectrometer was set up at 10 MHz
bandwidth with a 1 Hz resolution obtaining a spectrum every 5 min.
Observation results were saved as in two file format:
• SIV—the standard output file format of Sentinel IV spectrometer suitable for the
use of the old Sentinel IV post-processing software,
• RAW—the standard new spectrometers line file format for general SETI observations (a more straightforward and improved version of SIV) (see Fig. 7.14).
The comparison of the observation results, produced by both spectrometers, proved
a precise agreement between them (net of the technical parameters of the two
spectrometers such as spectra resolution and rate).
Post-processing of observations results showed no results in ETI signal detection
[40].