ETC Request ID: STIS.im.1163884

Exposure time (seconds) = 0.2000

gives: SNR = 352.4902

gives: Time to Saturation (for a single exposure) = 0.63 seconds

gives: Optimum SNR = 397.5805

Exposure time calculation HAD WARNINGS.

WARNING MESSAGE: This observation has a significant filter leak where 10.4 percent of the signal comes from outside the prescribed filter bandpass limits.

WARNING MESSAGE: "Electrons per pixel due to background (0.005) 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."


Plots

Detailed Information Count rate Total counts Associated noise
(e-/s) (e-) (e-)
Counts (circle with radius 0.207 arcsec)
    Source 639,748.238 127,949.65 357.70
    Background 1.357 0.27 0.52
        Sky 0.007 1.30e-03 0.04
        Dark Current 1.350 0.27 0.52
    Read Out 61.73
Total in selected region 639,749.594 127,949.92 362.99
Brightest Pixel (single exposure) 189,478.291 37,895.66
Global Count Rates
    Source only 799,685.297 159,937.059
    Background (sky+dark) 26,283.903 5,256.78
Background per unit area
    Sky Background (arcsec-2) 0.048 0.010
    Dark Current (arcsec-2) 10.000 2.000
Extraction region
circle with radius 0.207 arcsec
    Effective Sky Area (pixels) 53.72
    Fraction of flux 0.80
    Fraction of flux in brightest pixel 0.24
Effective Wavelength 5621.77 Å

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


Target: [point source]
Spectrum: Kurucz Models B5V 15400 3.9
Extinction E(B-V): Milky Way Diffuse (Rv=3.1) = 0.02 applied before normalization
Normalization: Renormalized to vegamag = 4.5 in filter Johnson/J
Redshift: None
Emission Lines: None


Selected background:
  Sky Background:
    Level:

Plots

These results were computed using: ETC version 26.1