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Space Telescope Imaging Spectrograph Instrument Handbook for Cycle 25 > Chapter 6: Exposure Time Calculations > 6.6 Tabular Sky Backgrounds

 6.6 Tabular Sky Backgrounds
We provide a table of the high sky background numbers as plotted in Figure 6.1, for easy reference. See the text and the caption in Figure 6.1 for more details. The high sky values are defined as the earthshine at 38° from the limb and by the high zodiacal light of mV = 22.1 arcsec-2. The contributions of the geocoronal emission lines are tabulated separately in Table 6.5.
 WavelengthÅ High Earthshineerg/s/cm2/ Å/arcsec2 High Zodiacal Lighterg/s/cm2/ Å/arcsec2 Total Backgrounderg/s/cm2/Å/arcsec2 1000 2.41e-23 9.69e-29 2.41e-23 1100 4.38e-22 1.04e-26 4.38e-22 1200 4.01e-23 1.08e-25 4.03e-23 1300 7.41e-25 6.59e-25 1.40e-24 1400 4.29e-25 2.55e-24 2.98e-24 1500 4.16e-25 9.73e-24 1.01e-23 1600 2.55e-25 2.35e-22 2.35e-22 1700 7.89e-25 7.21e-21 7.21e-21 1800 9.33e-23 1.53e-20 1.54e-20 1900 4.39e-22 2.25e-20 2.29e-20 2000 1.01e-21 3.58e-20 3.68e-20 2100 1.60e-21 1.23e-19 1.25e-19 2200 7.49e-22 2.21e-19 2.22e-19 2300 3.32e-22 1.81e-19 1.81e-19 2400 2.50e-22 1.83e-19 1.83e-19 2500 2.39e-22 2.53e-19 2.53e-19 2600 5.62e-22 3.06e-19 3.06e-19 2700 6.77e-21 1.01e-18 1.02e-18 2800 2.03e-21 2.88e-19 2.90e-19 2900 4.32e-20 2.08e-18 2.12e-18 3000 9.34e-20 1.25e-18 1.35e-18 3100 2.07e-19 1.50e-18 1.70e-18 3200 3.60e-19 2.30e-18 2.66e-18 3300 4.27e-19 2.95e-18 3.38e-18 3400 6.40e-19 2.86e-18 3.50e-18 3500 8.20e-19 2.79e-18 3.61e-18 3600 1.06e-18 2.74e-18 3.80e-18 3700 1.22e-18 3.32e-18 4.54e-18 3800 1.23e-18 3.12e-18 4.35e-18 3900 1.52e-18 3.34e-18 4.86e-18 4000 2.38e-18 4.64e-18 7.01e-18 4250 2.38e-18 4.65e-18 7.03e-18 4500 2.86e-18 5.58e-18 8.44e-18 4750 2.79e-18 5.46e-18 8.25e-18 5000 2.63e-18 5.15e-18 7.77e-18 5250 2.67e-18 5.37e-18 8.04e-18 5500 2.58e-18 5.34e-18 7.92e-18 5750 2.54e-18 5.40e-18 7.94e-18 6000 2.42e-18 5.25e-18 7.67e-18 6250 2.26e-18 5.02e-18 7.28e-18 6500 2.17e-18 4.92e-18 7.09e-18 6750 2.07e-18 4.79e-18 6.87e-18 7000 1.93e-18 4.55e-18 6.48e-18 7250 1.85e-18 4.43e-18 6.29e-18 7500 1.74e-18 4.23e-18 5.97e-18 7750 1.63e-18 4.04e-18 5.67e-18 8000 1.56e-18 3.92e-18 5.49e-18 8250 1.48e-18 3.76e-18 5.23e-18 8500 1.35e-18 3.50e-18 4.85e-18 8750 1.31e-18 3.43e-18 4.74e-18 9000 1.22e-18 3.23e-18 4.44e-18 9250 1.15e-18 3.07e-18 4.21e-18 9500 1.10e-18 2.98e-18 4.08e-18 9750 1.04e-18 2.86e-18 3.91e-18 10,000 1.00e-18 2.78e-18 3.78e-18 10,250 9.54e-19 2.67e-18 3.63e-18 10,500 9.04e-19 2.56e-18 3.46e-18 10,750 8.41e-19 2.41e-18 3.25e-18 11,000 8.03e-19 2.31e-18 3.11e-18
Table 6.5: Geocoronal (Airglow) Emission Lines
 Wavelength(Å) ID Line Width (Å) Intensity High Average Low kilo-Rayleighs erg/s/cm2/ kilo-Rayleighs erg/s/cm2/ kilo-Rayleighs erg s/cm2/ 1216 Lyα 0.04 ~20 6.1e-13 ~10 3.05e-13 2 6.1e-14 13021 O I 0.013 ~2 5.7e-14 ~1 2.85e-14 0.013 3.8e-16 1356 O I] 0.013 ~0.2 5e-15 ~0.1 2.50e-15 ~ 0.001 3e-17 2471 [O II] 0.023 < 0.2 3e-15 <0.1 1.50e-15 < 0.001 1.5e-17
Blend of 1302.2, 1304.9, and 1306.0 with intensity ratio 3:2:1.

Space Telescope Imaging Spectrograph Instrument Handbook for Cycle 25 > Chapter 6: Exposure Time Calculations > 6.6 Tabular Sky Backgrounds