ETC Request ID: STIS.sp.1184900

Exposure time (seconds) = 628.0000 at wavelength 1800.00 Å

gives: SNR = 50.2581 (per resolution element)

Exposure time calculation HAD WARNINGS.

WARNING MESSAGE: MAMA Bright limits: total count rate per image 89672.6 exceeds limit for irregularly-variable sources 40 percent of the bright limit 200000 counts per second

WARNING MESSAGE: Buffer time 22.3034 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 2.302 2,891.56 53.77
    Background 0.011 13.19 3.63
        Sky 9.189e-11 1.15e-07 3.40e-04
        Dark Current 0.011 13.19 3.63
Total in selected region 2.313 2,904.75 57.53
Brightest Pixel (single exposure) (at 2267.96 Å) 2.225 1,397.41
Count rate entire detector 89,672.607
Buffer Time (sec) 22.30
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 69,369.879 43,564,283.861
    Background (sky+dark) 1,572.864 987,758.62
Encircled energy fraction 0.92

Instrument name: STIS
Mode: spectroscopic
Detector: NUVMAMA
Central Wavelength: 1978
Grating: [E230M] R ~ 30000
Aperture: 0.2X0.2


Target: [point source]
Spectrum: Standard HST Star Spectra BD+28°4211 (Op, 10.51) [1140.6, 10242.7 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