ETC Request ID: STIS.sp.1165465

Requested Signal/Noise Ratio = 100.000 at wavelength 1500.00 Å (per resolution element)

gives: Time = 518.4687 seconds

Exposure time calculation HAD WARNINGS.

WARNING MESSAGE: MAMA Bright limits: total count rate per image 19384.6 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 9.645 10,001.09 100.01
    Background 0.001 1.09 1.04
        Sky 1.393e-10 1.44e-07 3.80e-04
        Dark Current 0.001 1.09 1.04
Total in selected region 9.646 10,002.18 100.01
Brightest Pixel (single exposure) (at 1269.30 Å) 11.457 5,939.87
Count rate entire detector 19,384.606
Buffer Time (sec) 103.17
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 18,097.182 9,382,822.152
    Background (sky+dark) 1,287.424 667,489.09
Encircled energy fraction 0.84

Instrument name: STIS
Mode: spectroscopic
Detector: FUVMAMA
Central Wavelength:
Grating: [G140L] R ~ 1000
Aperture: 52X2
Glow region: low


Target: [point source]
Spectrum: Standard HST Star Spectra HZ21 (DO2, 14.69) [1140.27, 10238.1 Å]
Extinction E(B-V): None
Normalization: None
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 26.1