ETC Request ID: STIS.im.1035907

Requested Signal/Noise Ratio = 100.000

gives: Time = 4.4445 seconds

gives: Time to Saturation (for a single exposure) = 43.15 seconds

gives: Optimum SNR = 403.1448

Exposure time calculation HAD WARNINGS.

WARNING MESSAGE: This observation has a significant filter leak where 86 percent of the signal comes from outside the prescribed filter bandpass limits.

WARNING MESSAGE: "Electrons per pixel due to background (0.04) 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 3.11 arcsec)
    Source 29,921.765 132,987.63 364.67
    Background 220.266 978.98 31.29
        Sky 1.476 6.56 2.56
        Dark Current 218.790 972.41 31.18
    Read Out 1,278.52
Total in selected region 30,142.031 133,966.61 1,329.88
Brightest Pixel (single exposure) 2,780.898 6,179.87
Global Count Rates
    Source only 37,402.206 166,234.539
    Background (sky+dark) 18,944.019 84,196.91
Background per unit area
    Sky Background (arcsec-2) 0.049 0.216
    Dark Current (arcsec-2) 7.200 32.000
Extraction region
circle with radius 3.11 arcsec
    Effective Sky Area (pixels) 12,154.04
    Fraction of flux 0.80
    Fraction of flux in brightest pixel 0.07
Effective Wavelength 10176.54 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 O7 V
Extinction E(B-V): Milky Way Diffuse (Rv=3.1) = 1.96 applied before normalization
Normalization: Renormalized to vegamag = 5.2 in filter Johnson/J
Redshift: None
Emission Lines: None


Selected background:
  Sky Background:
    Level:

Plots

These results were computed using: ETC version 25.2