ETC Request ID: STIS.im.1035934

Requested Signal/Noise Ratio = 100.000

gives: Time = 0.0270 seconds

gives: Time to Saturation (for a single exposure) = 0.73 seconds

gives: Optimum SNR = 125.0030

Exposure time calculation HAD WARNINGS.

WARNING MESSAGE: Result of the calculation 0.013476 is less than the minimum exposure time for this detector (0.1)

WARNING MESSAGE: This observation has a significant filter leak where 9.91 percent of the signal comes from outside the prescribed filter bandpass limits.

WARNING MESSAGE: "Electrons per pixel due to background (0.00024) 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 0.207 arcsec)
    Source 552,101.997 14,880.26 121.98
    Background 0.979 0.03 0.16
        Sky 0.007 1.75e-04 0.01
        Dark Current 0.972 0.03 0.16
    Read Out 85.22
Total in selected region 552,102.976 14,880.28 148.80
Brightest Pixel (single exposure) 164,027.956 2,210.44

Global Count Rates
    Source only 690,127.496 18,600.320
    Background (sky+dark) 18,944.019 510.58

Background per unit area
    Sky Background (arcsec-2) 0.049 0.001
    Dark Current (arcsec-2) 7.200 0.194

Extraction region
circle with radius 0.207 arcsec
    Effective Sky Area (pixels) 53.61
    Fraction of flux 0.80
    Fraction of flux in brightest pixel 0.24
Effective Wavelength 5593.57 Å


Instrument name: STIS
Mode: imaging
Detector: CCD
Aperture: F28X50OIII
Gain: 4.0
# Frames: 2
Binning: 1
Dark: medium


Target: [point source]
Spectrum: Bruzual Synthetic Stellar Spectra O9 III
Extinction E(B-V): Milky Way Diffuse (Rv=3.1) = 0.1 applied before normalization
Normalization: Renormalized to vegamag = 4.7 in filter Johnson/J
Redshift: None
Emission Lines: None


Selected background:
  Sky Background:
    Level:


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These results were computed using: ETC version 25.2