ETC Request ID: STIS.sp.827930

Exposure time (seconds) = 250.0000 at wavelength 1854.00 Å

gives: SNR = 21.6913 (per resolution element)

Exposure time calculation HAD WARNINGS.

WARNING MESSAGE: Buffer time 37.4121 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 1.050 525.15 22.92
    Background 0.011 5.25 2.29
        Sky 1.634e-12 8.17e-10 2.86e-05
        Dark Current 0.011 5.25 2.29
Total in selected region 1.061 530.40 24.21
Brightest Pixel (single exposure) (at 1929.40 Å) 0.477 119.32
Count rate entire detector 53,458.667

Buffer Time (sec) 37.41
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 33,539.414 8,384,853.594
    Background (sky+dark) 1,572.864 393,216.00

Encircled energy fraction 0.92


Instrument name: STIS
Mode: spectroscopic
Detector: NUVMAMA
Central Wavelength: 1813
Grating: [E230H] R ~ 114000
Aperture: 0.1X0.03


Target: [point source]
Spectrum: Bruzual Synthetic Stellar Spectra O8 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