ETC Request ID: STIS.sp.1006230

Exposure time (seconds) = 2,000.0000 at wavelength 1978.00 Å

gives: SNR = 102.9727 (per resolution element)

Exposure time calculation HAD WARNINGS.

WARNING MESSAGE: MAMA Bright limits: total count rate per image 119348 exceeds limit for irregularly-variable sources 40 percent of the bright limit 200000 counts per second

WARNING MESSAGE: Buffer time 16.7578 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 7 pix) (2 pix resel x 7 pix)
    Source 2.928 11,713.34 108.23
    Background 0.011 42.00 6.48
        Sky 1.281e-10 5.12e-07 7.16e-04
        Dark Current 0.011 42.00 6.48
Total in selected region 2.939 11,755.34 113.75
Brightest Pixel (single exposure) (at 2240.98 Å) 5.271 10,541.66
Count rate entire detector 119,347.510
Buffer Time (sec) 16.76
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 92,736.000 185,472,000.952
    Background (sky+dark) 1,572.864 3,145,728.02
Encircled energy fraction 0.93

Instrument name: STIS
Mode: spectroscopic
Detector: NUVMAMA
Central Wavelength: 1978
Grating: [E230M] R ~ 30000
Aperture: 0.2X0.06


Target: [point source]
Spectrum: Castelli-Kurucz Models F2V 7000 4.0
Extinction E(B-V): None
Normalization: Renormalized to vegamag = 4.47 in filter Johnson/V
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 25.2