ETC Request ID: STIS.sp.827693

Exposure time (seconds) = 300.0000 at wavelength 1250.00 Å

gives: SNR = 28.3995 (per resolution element)

Exposure time calculation HAD WARNINGS.

WARNING MESSAGE: MAMA Bright limits: total count rate per image 105299 exceeds limit for irregularly-variable sources 40 percent of the bright limit 200000 counts per second

WARNING MESSAGE: Buffer time 18.9935 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 1.655 992.96 31.51
    Background 0.001 0.63 0.79
        Sky 2.530e-15 1.52e-12 1.23e-06
        Dark Current 0.001 0.63 0.79
Total in selected region 1.656 993.59 34.96
Brightest Pixel (single exposure) (at 1316.38 Å) 1.228 368.42
Count rate entire detector 105,299.115
Buffer Time (sec) 18.99
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 57,772.823 17,331,846.906
    Background (sky+dark) 157.296 47,188.93
Encircled energy fraction 0.90

Instrument name: STIS
Mode: spectroscopic
Detector: FUVMAMA
Central Wavelength: 1234
Grating: [E140H] R ~ 114000
Aperture: 0.1X0.03
Glow region: low


Target: [point source]
Spectrum: Bruzual Synthetic Stellar Spectra B8 V
Extinction E(B-V): None
Normalization: Flux 1.7e-10 flam at 1360.0 Å
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 24.2