ETC Request ID: STIS.im.1013928

Exposure time (seconds) = 0.1000

gives: SNR = 852.1445

gives: Time to Saturation (for a single exposure) = 0.07 seconds

gives: Optimum SNR = 954.5796

Exposure time calculation HAD WARNINGS.

WARNING MESSAGE: CCD Full Well limits: total counts per native pixel 177445 exceeds bright limit 120000 for selected gain

WARNING MESSAGE: "Electrons per pixel due to background (0.01) is less than the recommended threshold of 20 electrons to avoid poor charge transfer efficiency (CTE). We suggest you consider CTE mitigation strategies described in the STIS Instrument Handbook."


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Detailed Information Count rate Total counts Associated noise
(e-/s) (e-) (e-)
Counts (circle with radius 0.226 arcsec)
    Source 7,304,955.244 730,495.52 854.69
    Background 6.524 0.65 0.81
        Sky 5.354 0.54 0.73
        Dark Current 1.170 0.12 0.34
    Read Out 66.11
Total in selected region 7,304,961.767 730,496.18 857.24
Brightest Pixel (single exposure) 1,774,446.959 177,444.70
Global Count Rates
    Source only 9,131,194.055 913,119.405
    Background (sky+dark) 106,019.251 10,601.93
Background per unit area
    Sky Background (arcsec-2) 33.243 3.324
    Dark Current (arcsec-2) 7.200 0.720
Extraction region
circle with radius 0.226 arcsec
    Effective Sky Area (pixels) 64.42
    Fraction of flux 0.80
    Fraction of flux in brightest pixel 0.19
Effective Wavelength 7046.44 Å

Instrument name: STIS
Mode: imaging
Detector: CCD
Aperture: 50CCD
Gain: 4.0
# Frames: 1
Binning: 1
Dark: medium


Target: [point source]
Spectrum: Kurucz Models K7V 4060 4.5
Extinction E(B-V): None
Normalization: Renormalized to vegamag = 8.971 in filter Johnson/V
Redshift: None
Emission Lines: None


Selected background:
  Sky Background:
    Level:

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These results were computed using: ETC version 25.2