ETC Request ID: STIS.sp.1303649

Exposure time (seconds) = 1,590.0000 at wavelength 2497.00 Å

gives: SNR = 176.8968 (per resolution element)

Exposure time calculation HAD WARNINGS.

WARNING MESSAGE: MAMA Bright limits: total count rate per image 12762.9 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 9.854 31,336.94 177.02
    Background 0.014 44.52 6.67
        Sky 1.397e-08 4.44e-05 6.67e-03
        Dark Current 0.014 44.52 6.67
Total in selected region 9.868 31,381.46 177.15
Brightest Pixel (single exposure) (at 2504.94 Å) 5.378 8,550.36
Count rate entire detector 12,762.944
Buffer Time (sec) 156.70
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 10,665.340 16,957,890.667
    Background (sky+dark) 2,097.604 3,335,190.60
Encircled energy fraction 0.86

Instrument name: STIS
Mode: spectroscopic
Detector: NUVMAMA
Central Wavelength: 2499
Grating: [G230M] R ~ 10000
Aperture: 52X0.1


Target: [point source]
Spectrum: Kurucz Models F2V 6890 4.3
Extinction E(B-V): None
Normalization: Renormalized to vegamag = 5.946 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 26.2