ETC Request ID: STIS.sp.1431086

Requested Signal/Noise Ratio = 30.000 at wavelength 1550.00 Å (per resolution element)

gives: Time = 379.2918 seconds

Exposure time calculation HAD WARNINGS.

WARNING MESSAGE: MAMA Bright limits: total count rate per image 133864 exceeds limit for irregularly-variable sources 40 percent of the bright limit 200000 counts per second

WARNING MESSAGE: Buffer time 14.9406 is less than minimum 99 seconds.

WARNING MESSAGE: Partial overlap between instrument throughput band and target spectrum. Please doublecheck the wavelength range covered by the selected spectrum, and the instrument documentation for the selected filter.


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 1.315 997.81 31.59
    Background 0.001 0.80 0.89
        Sky 3.947e-16 2.99e-13 5.47e-07
        Dark Current 0.001 0.80 0.89
Total in selected region 1.316 998.61 33.26
Brightest Pixel (single exposure) (at 1435.94 Å) 1.453 551.28
Count rate entire detector 133,863.779
Buffer Time (sec) 14.94
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 80,545.965 30,550,421.716
    Background (sky+dark) 157.286 59,657.47
Encircled energy fraction 0.95

Instrument name: STIS
Mode: spectroscopic
Detector: FUVMAMA
Central Wavelength: 1425
Grating: [E140M] R ~ 45800
Aperture: 0.2X0.05ND
Glow region: low


Target: [point source]
Spectrum: User uploaded spectrum: zeta-Oph.IUE-SHORT
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