ETC Request ID: STIS.sp.1012961

Exposure time (seconds) = 0.3000 at wavelength 6564.00 Å

gives: SNR = 1,063.4856 (per resolution element)

gives: Time to Saturation (for a single exposure) = 0.08 seconds

Exposure time calculation HAD WARNINGS.

WARNING MESSAGE: CCD Full Well limits: total counts per native pixel 222080 exceeds bright limit 120000 for selected gain

WARNING MESSAGE: "Electrons per pixel due to background (0.0027) 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."


Table of Source and Noise Counts per Pixel

Plots

Detailed Information Count rate Total counts Associated noise
(e-/s) (e-) (e-)
Counts (box 7 pixels high) (1 pix x 7 pix) (2 pix resel x 7 pix)
    Source 1,888,135.342 1,132,881.20 1,064.37
    Background 0.126 0.08 0.28
        Sky 4.582e-05 2.75e-05 5.24e-03
        Dark Current 0.126 0.08 0.27
    Read Out 43.39
Total in selected region 1,888,135.468 1,132,881.28 1,065.25
Brightest Pixel (single exposure) (at 6295.55 Å) 1,480,530.787 222,079.62
Global Count Rates
    Source only 3,276,179,842.448 982,853,952.735
    Background (sky+dark) 18,881.893 5,664.57
Encircled energy fraction 0.91

Instrument name: STIS
Mode: spectroscopic
Detector: CCD
Central Wavelength: 6581
Grating: [G750M] R ~ 5000
Aperture: 52X0.05
Gain: 4.0
# Frames: 2
Binning: dispersion: 1, spatial: 1
Dark: medium


Target: [point source]
Spectrum: Standard HST Star Spectra Sirius (A2V, -1.46) [900.5, 2.997e6 Å]
Extinction E(B-V): None
Normalization: None
Redshift: None
Emission Lines: None


Selected background:
  Sky Background:
    Level:

Table of Source and Noise Counts per Pixel

Plots

These results were computed using: ETC version 25.2