ETC Request ID: STIS.sp.1364661

Exposure time (seconds) = 2,200.0000 at wavelength 1355.00 Å

gives: SNR = 279.8723 (per resolution element)

Exposure time calculation HAD WARNINGS.

WARNING MESSAGE: MAMA Bright limits: total count rate per image 12407.2 exceeds limit for irregularly-variable sources 40 percent of the bright limit 30000 counts per second


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 17.803 78,333.11 279.88
    Background 0.001 4.62 2.15
        Sky 1.867e-11 8.22e-08 2.87e-04
        Dark Current 0.001 4.62 2.15
Total in selected region 17.804 78,337.73 279.89
Brightest Pixel (single exposure) (at 1334.70 Å) 5.649 12,428.32
Count rate entire detector 12,407.193
Buffer Time (sec) 161.20
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 11,121.296 24,466,851.772
    Background (sky+dark) 1,285.897 2,828,972.91
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: Kurucz Models O5V 44500 5.0
Extinction E(B-V): Milky Way Diffuse (Rv=3.1) = 0.558 applied before normalization
Normalization: Renormalized to vegamag = 11.84 in filter Johnson/B
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 27.2