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Laboratory for Atmospheric and Space Physics

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*
ε Per 3 57.8 40 0 2.90 B0.5 III 2 a,b,g
α Cma 6 45.1 -16 43 -1.46 A1 V 10 a,b,g
κ Vel 9 22.1 -55 1 2.50 B2 IV-V 2 b
α Leo 10 8.4 11 58 1.35 B7 V 7 a,b,e
δ Cen 12 8.4 -50 43 2.60 B2 IVne 4 a,b
α Cru 12 26.6 -63 7 1.35 B0.5 IV + B1 V 9 b
α Vir 13 25.1 -11 10 0.97 B1 IV + B2 V 9 b,d,e,f
η uma 13 47.5 49 15 1.86 B3 V 7 a – e,h
ζ Cen 13 55.5 -47 17 2.55 B2.5 IV 7 a,b
β Cen 14 3.8 -60 22 0.61 B1 III 7 a,b
γ Lup 15 35.1 -41 10 2.78 B2 IV 3 a,b
δ Sco 16 0.3 -22 37 2.32 B0.5 IV 2 a,b
τ Sco 16 35.9 -28 13 2.82 B0 V 4 a,b
α Lyr 18 36.9 38 47 0.03 A0 Va 2 a,b,
σ Sgr 18 55.3 -26 18 2.02 B2.5 V 3 a,b
α Pav 20 25.6 -56 44 1.94 B2.5 V 4 a,b
α Gru 22 8.2 -46 58 1.74 B7 IV 2 a,b,d
α 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].