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    In-flight Calibration
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 SOLar STellar Irradiance Comparison Experiment (SOLSTICE) header end
In-Flight Calibration

The in-flight calibration for the SOLSTICE instruments includes long-term multi-wavelength observations of bright, blue stars, and redundant channels. The wavelength calibration for the in-flight data uses the many well-known solar emission features to determine the wavelength scale. Retrieval of solar irradiance requires detailed knowledge of long term sensitivity changes in the SOLSTICE instruments. These changes, which result primarily from exposure to solar radiation, are measured by observing an ensemble of bright O-B stars. Table 2 lists the stars used to track changes in the UARS SOLSTICE instrument. The same stars will be used during the SORCE mission.

Table 2: UARS SOLSTICE Calibration Stars
Star Name RA (2000) Dec (2000) V Mag Spec Type Priority Calibration*
epsilon Per 3 57.8 40 0 2.90 B0.5 III 2 a,b,g
alpha Cma 6 45.1 -16 43 -1.46 A1 V 10 a,b,g
kappa Vel 9 22.1 -55 1 2.50 B2 IV-V 2 b
alpha Leo 10 8.4 11 58 1.35 B7 V 7 a,b,e
delta Cen 12 8.4 -50 43 2.60 B2 IVne 4 a,b
alpha Cru 12 26.6 -63 7 1.35 B0.5 IV + B1 V 9 b
alpha Vir 13 25.1 -11 10 0.97 B1 IV + B2 V 9 b,d,e,f
eta uma 13 47.5 49 15 1.86 B3 V 7 a - e,h
zeta Cen 13 55.5 -47 17 2.55 B2.5 IV 7 a,b
beta Cen 14 3.8 -60 22 0.61 B1 III 7 a,b
gamma Lup 15 35.1 -41 10 2.78 B2 IV 3 a,b
delta Sco 16 0.3 -22 37 2.32 B0.5 IV 2 a,b
tau Sco 16 35.9 -28 13 2.82 B0 V 4 a,b
alpha Lyr 18 36.9 38 47 0.03 A0 Va 2 a,b,c
sigma Sgr 18 55.3 -26 18 2.02 B2.5 V 3 a,b
alpha Pav 20 25.6 -56 44 1.94 B2.5 V 4 a,b
alpha Gru 22 8.2 -46 58 1.74 B7 IV 2 a,b,d
alpha PsA 22 57.7 -29 37 1.16 A3 V 2 a,b

 

Table 3: UARS SOLSTICE Calibration Dark Regions
Region RA (2000) DEC (2000) Priority Calibration
1 0h 0.0m 71° 0' 8 -
2 0 48.0 -80 0 6 -
3 3 44.0 28 0 10 -
4 4 28.1 -18 48 6 i
5 7 20.0 -84 0 10 -
6 8 16.0 32 0 10 -
7 9 56.1 -43 0 10 -
8 10 56.0 74 48 7 i
9 14 44.0 85 0 10 -
10 15 40.0 -57 0 10 -
11 15 48.0 -11 0 10 -
12 17 44.0 35 0 10 -
13 20 5.9 -20 0 10 b
14 21 44.0 33 0 10 -
* (a) td-1 [Jamar et al., 1976; Macau-Hercot et al., 1978]; (b) Voyager [Holberg et al., 1982]; (c) rocket [Bohlin et al., 1974]; (d) Apollo 17 [Henry et al., 1975]; (e) rocket [Bless et al., 1976]; (f) rocket [Brune et al., 1979]; (g) rocket [Woods et al., 1985]; (h) IuE [Bohlin et al., 1980]; (i) shuttle uVX [Tennyson et al., 1987].