ETC Request ID: STIS.im.1163880

Exposure time (seconds) = 3.0000

gives: SNR = 226.3481

gives: Time to Saturation (for a single exposure) = 19.91 seconds

gives: Optimum SNR = 402.7767

Exposure time calculation HAD WARNINGS.

WARNING MESSAGE: This observation has a significant filter leak where 70.7 percent of the signal comes from outside the prescribed filter bandpass limits.

WARNING MESSAGE: "Electrons per pixel due to background (0.075) 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 1.52 arcsec)
    Source 43,784.029 131,352.09 362.43
    Background 73.052 219.16 14.80
        Sky 0.352 1.06 1.03
        Dark Current 72.700 218.10 14.77
    Read Out 452.98
Total in selected region 43,857.082 131,571.25 580.31
Brightest Pixel (single exposure) 6,027.488 18,082.46
Global Count Rates
    Source only 54,730.037 164,190.110
    Background (sky+dark) 26,283.903 78,851.71
Background per unit area
    Sky Background (arcsec-2) 0.048 0.145
    Dark Current (arcsec-2) 10.000 30.000
Extraction region
circle with radius 1.52 arcsec
    Effective Sky Area (pixels) 2,907.76
    Fraction of flux 0.80
    Fraction of flux in brightest pixel 0.11
Effective Wavelength 9252.91 Å

Instrument name: STIS
Mode: imaging
Detector: CCD
Aperture: F28X50OIII
Gain: 4.0
# Frames: 1
Binning: 1
Dark: medium


Target: [point source]
Spectrum: Kurucz Models B5V 15400 3.9
Extinction E(B-V): Milky Way Diffuse (Rv=3.1) = 1.4 applied before normalization
Normalization: Renormalized to vegamag = 5.1 in filter Johnson/J
Redshift: None
Emission Lines: None


Selected background:
  Sky Background:
    Level:

Plots

These results were computed using: ETC version 26.1