ETC Request ID: STIS.sp.939708

Exposure time (seconds) = 600.0000 at wavelength 1400.00 Å

gives: SNR = 164.5092 (per resolution element)

Exposure time calculation HAD WARNINGS.

WARNING MESSAGE: MAMA Bright limits: total count rate per image 21873.8 exceeds limit for irregularly-variable sources 40 percent of the bright limit 30000 counts per second

WARNING MESSAGE: Buffer time 91.4335 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 pix) (2.0 pix resel x pix)
    Source 22.554 27,064.54 164.51
    Background 0.001 1.26 1.12
        Sky 2.432e-11 2.92e-08 1.71e-04
        Dark Current 0.001 1.26 1.12
Total in selected region 22.555 27,065.80 164.52
Brightest Pixel (single exposure) (at 1278.30 Å) 12.013 7,207.80
Count rate entire detector 21,873.819
Buffer Time (sec) 91.43
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 20,571.055 12,342,632.968
    Background (sky+dark) 1,302.764 781,658.52
Encircled energy fraction 0.82

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


Target: [point source]
Spectrum: Castelli-Kurucz Models O3V 45000 4.5
Extinction E(B-V): Milky Way Diffuse (Rv=3.1) = 0.1 applied before normalization
Normalization: Renormalized to abmag = 12.8 in filter WFC3/UVIS1/F225W
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 25.1.1