ETC Request ID: STIS.im.825315

Exposure time (seconds) = 7.0000

gives: SNR = 359.5376

gives: Time to Saturation (for a single exposure) = 17.90 seconds

gives: Optimum SNR = 405.6064

Exposure time calculation HAD WARNINGS.

WARNING MESSAGE: "Electrons per pixel due to background (0.13) 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 0.194 arcsec)
    Source 18,950.436 132,653.05 364.22
    Background 0.918 6.42 2.53
        Sky 0.006 0.04 0.20
        Dark Current 0.912 6.38 2.53
    Read Out 58.89
Total in selected region 18,951.353 132,659.47 368.95
Brightest Pixel (single exposure) 6,703.682 46,925.77
Global Count Rates
    Source only 23,688.044 165,816.311
    Background (sky+dark) 19,990.111 139,930.78
Background per unit area
    Sky Background (arcsec-2) 0.047 0.328
    Dark Current (arcsec-2) 7.600 53.200
Extraction region
circle with radius 0.194 arcsec
    Effective Sky Area (pixels) 47.35
    Fraction of flux 0.80
    Fraction of flux in brightest pixel 0.28
Effective Wavelength 3739.88 Å

Instrument name: STIS
Mode: imaging
Detector: CCD
Aperture: F28X50OII
Gain: 4.0
# Frames: 1
Binning: 1
Dark:


Target: [point source]
Spectrum: Kurucz Models F2V 6890 4.3
Extinction E(B-V): None
Normalization: Renormalized to vegamag = 8.54 in filter Johnson/V
Redshift: None
Emission Lines: None


Selected background:
  Sky Background:
    Level:

Plots

These results were computed using: ETC version 24.2