ETC Request ID: STIS.sp.827696

Exposure time (seconds) = 300.0000 at wavelength 2374.00 Å

gives: SNR = 35.7387 (per resolution element)

Exposure time calculation HAD WARNINGS.

WARNING MESSAGE: MAMA Bright limits: total count rate per image 86941.1 exceeds limit for irregularly-variable sources 40 percent of the bright limit 200000 counts per second

WARNING MESSAGE: Buffer time 23.0041 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 2.262 1,357.25 36.84
    Background 0.011 6.30 2.51
        Sky 8.811e-11 5.29e-08 2.30e-04
        Dark Current 0.011 6.30 2.51
Total in selected region 2.273 1,363.55 37.98
Brightest Pixel (single exposure) (at 2303.79 Å) 0.902 270.67
Count rate entire detector 86,941.128
Buffer Time (sec) 23.00
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 62,863.147 18,858,943.998
    Background (sky+dark) 1,572.864 471,859.20
Encircled energy fraction 0.93

Instrument name: STIS
Mode: spectroscopic
Detector: NUVMAMA
Central Wavelength: 2263
Grating: [E230H] R ~ 114000
Aperture: 0.1X0.03


Target: [point source]
Spectrum: Bruzual Synthetic Stellar Spectra B8 V
Extinction E(B-V): None
Normalization: Flux 3.8e-11 flam at 2026.0 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