ETC Request ID: STIS.im.1184300

Exposure time (seconds) = 0.1000

gives: SNR = 73.6503

gives: Time to Saturation (for a single exposure) = 1.66 seconds

gives: Optimum SNR = 97.5021

Exposure time calculation HAD WARNINGS.

WARNING MESSAGE: Result of the calculation 0.05 is less than the minimum exposure time for this detector (0.1)

WARNING MESSAGE: "Electrons per pixel due to background (0.0013) 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 0.251 arcsec)
    Source 90,091.349 9,009.13 94.92
    Background 2.000 0.20 0.45
        Sky 7.868e-05 7.87e-06 2.80e-03
        Dark Current 2.000 0.20 0.45
    Read Out 77.16
Total in selected region 90,093.349 9,009.33 122.32
Brightest Pixel (single exposure) 19,827.665 991.38
Global Count Rates
    Source only 112,614.186 11,261.419
    Background (sky+dark) 26,214.648 2,621.46
Background per unit area
    Sky Background (arcsec-2) 3.968e-04 3.968e-05
    Dark Current (arcsec-2) 10.000 1.000
Extraction region
circle with radius 0.251 arcsec
    Effective Sky Area (pixels) 79.31
    Fraction of flux 0.80
    Fraction of flux in brightest pixel 0.18
Effective Wavelength 7552.24 Å

Instrument name: STIS
Mode: imaging
Detector: CCD
Aperture: F25ND5
Gain: 1.0
# Frames: 2
Binning: 1
Dark: medium


Target: [point source]
Spectrum: Castelli-Kurucz Models K2V 4750 4.5
Extinction E(B-V): None
Normalization: Renormalized to vegamag = 1.33 in filter Johnson/V
Redshift: None
Emission Lines: None


Selected background:
  Sky Background:
    Level:

Plots

These results were computed using: ETC version 26.1