ETC Request ID: STIS.sp.1184850

Exposure time (seconds) = 331.0000 at wavelength 1675.00 Å

gives: SNR = 55.8389 (per resolution element)

Exposure time calculation HAD WARNINGS.

WARNING MESSAGE: MAMA Bright limits: total count rate per image 29114.1 exceeds limit for irregularly-variable sources 40 percent of the bright limit 30000 counts per second

WARNING MESSAGE: Buffer time 68.6952 is less than minimum 99 seconds.


Table of Source and Noise Counts per Pixel

Plots

Detailed Information Count rate Total counts Associated noise
(counts/s) (counts) (counts)
Counts (box 7 pixels high) (1 pix x 7 pix) (2 pix resel x 7 pix)
    Source 4.711 3,118.68 55.85
    Background 0.001 0.70 0.83
        Sky 5.165e-09 3.42e-06 1.85e-03
        Dark Current 0.001 0.70 0.83
Total in selected region 4.712 3,119.37 55.85
Brightest Pixel (single exposure) (at 1286.10 Å) 18.596 6,155.16
Count rate entire detector 29,114.102
Buffer Time (sec) 68.70
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 27,826.678 9,210,630.309
    Background (sky+dark) 1,287.424 426,137.39
Encircled energy fraction 0.85

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 Grw+70°5824 (DA3, 12.77) [1140.56, 24976.7 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 26.1