ETC Request ID: STIS.sp.1407026

Exposure time (seconds) = 1,000.0000 at wavelength 1425.00 Å

gives: SNR = 158.5085 (per resolution element)

Exposure time calculation HAD WARNINGS.

WARNING MESSAGE: MAMA Bright limits: total count rate per image 16788.5 exceeds limit for irregularly-variable sources 40 percent of the bright limit 30000 counts per second


Table of Source and Noise Counts per Pixel

Plots

Detailed Information Count rate Total counts Associated noise
(counts/s) (counts) (counts)
Counts (box 11 pixels high) (1 pix x 11 pix) (2 pix resel x 11 pix)
    Source 12.564 25,128.25 158.52
    Background 0.002 3.30 1.82
        Sky 4.480e-11 8.96e-08 2.99e-04
        Dark Current 0.002 3.30 1.82
Total in selected region 12.566 25,131.55 158.53
Brightest Pixel (single exposure) (at 1273.50 Å) 6.593 6,592.61
Count rate entire detector 16,788.471
Buffer Time (sec) 119.13
For APT purposes, the recommended buffer time should be 4/5 of the buffer time calculated above. Please refer to the STIS Instrument Handbook for more details.
Global Count Rates
    Source only 15,503.171 15,503,170.926
    Background (sky+dark) 1,285.300 1,285,299.93
Encircled energy fraction 0.72

Instrument name: STIS
Mode: spectroscopic
Detector: FUVMAMA
Central Wavelength:
Grating: [G140L] R ~ 1000
Aperture: 52X2
Glow region: low


Target: [point source]
Spectrum: Standard HST Star Spectra WD1057+719 (DA1.2, 14.8) [900.0, 300000.0 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 28.1