80
2 Observations of Radio and X-ray Pulsars
Table 2.3 Performance indicators of RXTE’s payload
Indicator term
PCA
HEXTE
ASK
Energy range (keV)
2−60
15−250
2−12
Energy resolution
18%@6keV
15%@6keV
−
Time resolution
1μs
8 m s
80% of the sky
every 90 minutes
Spatial resolution
1°×1° FWHM
1°×1° (FWHM)
3′×15′
Sensitivity
(×10
-3
Crab)
0.1
1000
30
Collecting area (cm
2
)
6500
2×800
90
Detector
5 proportional
counters
2 clusters of 4
NaI/CsI scintillation
counters
Xenon proportional
counter,
position-sensitive
coronae; to infer the size of the smallest known black hole. Until January 3, 2012,
the RXTE became invalid and ceased scientific observations.
2.8.5 Chandra X-ray Observatory
The Chandra X-ray Observatory (CXO) was named after an Indian-American astrophysicist Subrahmanyan Chandrasekhar (1910–1995), and previously known as the
Advanced X-ray Astrophysics Facility (AXAF). On July 23, 1999, the CXO carried
on Space Shuttle Columbia was successfully launched by the NASA into a highly
elliptical orbit with the eccentricity of 0.744, the perigee of 14,308 km, the apogee
of 134,528 km and the inclination of 76.7°. The CXO applied to detecting the soft
X-rays from the universe is one of the four Great Observatories operated by the
NASA. Other Great Observatories are, respectively, the Hubble Space Telescope
(HST) applied to observing in the visible light and ultraviolet, the Compton Gamma
Ray Observatory (CGRO) applied to observing the hard X-rays and gamma rays
and the Spitzer Space Telescope (SST) applied to observing the infrared. Currently,
except for the CGRO becoming invalid, others are ongoing to work normally in the
orbits.
The CXO used a Wolter-type telescope with four pairs of nested mirrors, together
with their support structure, called the high-resolution mirror assembly; the mirror
substrate is 2-cm-thick glass, with the reflecting surface of a 33 nm iridium coating,
and the diameters are, respectively, 65 cm, 87 cm, 99 cm and 123 cm. The thick
substrate and particularly careful polishing allowed a very precise optical surface,
which is responsible for CXO’s unmatched resolution: between 80% and 95% of the
2 Observations of Radio and X-ray Pulsars
Table 2.3 Performance indicators of RXTE’s payload
Indicator term
PCA
HEXTE
ASK
Energy range (keV)
2−60
15−250
2−12
Energy resolution
18%@6keV
15%@6keV
−
Time resolution
1μs
8 m s
80% of the sky
every 90 minutes
Spatial resolution
1°×1° FWHM
1°×1° (FWHM)
3′×15′
Sensitivity
(×10
-3
Crab)
0.1
1000
30
Collecting area (cm
2
)
6500
2×800
90
Detector
5 proportional
counters
2 clusters of 4
NaI/CsI scintillation
counters
Xenon proportional
counter,
position-sensitive
coronae; to infer the size of the smallest known black hole. Until January 3, 2012,
the RXTE became invalid and ceased scientific observations.
2.8.5 Chandra X-ray Observatory
The Chandra X-ray Observatory (CXO) was named after an Indian-American astrophysicist Subrahmanyan Chandrasekhar (1910–1995), and previously known as the
Advanced X-ray Astrophysics Facility (AXAF). On July 23, 1999, the CXO carried
on Space Shuttle Columbia was successfully launched by the NASA into a highly
elliptical orbit with the eccentricity of 0.744, the perigee of 14,308 km, the apogee
of 134,528 km and the inclination of 76.7°. The CXO applied to detecting the soft
X-rays from the universe is one of the four Great Observatories operated by the
NASA. Other Great Observatories are, respectively, the Hubble Space Telescope
(HST) applied to observing in the visible light and ultraviolet, the Compton Gamma
Ray Observatory (CGRO) applied to observing the hard X-rays and gamma rays
and the Spitzer Space Telescope (SST) applied to observing the infrared. Currently,
except for the CGRO becoming invalid, others are ongoing to work normally in the
orbits.
The CXO used a Wolter-type telescope with four pairs of nested mirrors, together
with their support structure, called the high-resolution mirror assembly; the mirror
substrate is 2-cm-thick glass, with the reflecting surface of a 33 nm iridium coating,
and the diameters are, respectively, 65 cm, 87 cm, 99 cm and 123 cm. The thick
substrate and particularly careful polishing allowed a very precise optical surface,
which is responsible for CXO’s unmatched resolution: between 80% and 95% of the