ETC Request ID: STIS.im.1184308

Exposure time (seconds) = 0.1000

gives: SNR = 140.6023

gives: Time to Saturation (for a single exposure) = 0.59 seconds

gives: Optimum SNR = 167.3072

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 0.231 arcsec)
    Source 239,468.230 23,946.82 154.75
    Background 1.700 0.17 0.41
        Sky 6.678e-05 6.68e-06 2.58e-03
        Dark Current 1.700 0.17 0.41
    Read Out 71.14
Total in selected region 239,469.931 23,946.99 170.32
Brightest Pixel (single exposure) 55,841.010 2,792.05
Global Count Rates
    Source only 299,335.288 29,933.529
    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 0.231 arcsec
    Effective Sky Area (pixels) 67.33
    Fraction of flux 0.80
    Fraction of flux in brightest pixel 0.19
Effective Wavelength 7262.50 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 G2V 5750 4.5
Extinction E(B-V): None
Normalization: Renormalized to vegamag = 0.01 in filter Johnson/V
Redshift: None
Emission Lines: None


Selected background:
  Sky Background:
    Level:

Plots

These results were computed using: ETC version 26.1