ETC Request ID: STIS.sp.824674

Exposure time (seconds) = 100.0000 at wavelength 1600.00 Å

gives: SNR = 4.3796 (per resolution element)

Exposure time calculation HAD WARNINGS.

WARNING MESSAGE: MAMA Bright limits: total count rate per image 17751.1 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 pix) (2.0 pix resel x pix)
    Source 0.105 21.09 4.59
    Background 0.011 2.10 1.45
        Sky 3.139e-10 6.28e-08 2.51e-04
        Dark Current 0.011 2.10 1.45
Total in selected region 0.116 23.19 4.82
Brightest Pixel (single exposure) (at 2584.00 Å) 8.815 881.54
Count rate entire detector 17,751.105
Buffer Time (sec) 112.67
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 16,160.969 1,616,096.856
    Background (sky+dark) 1,590.136 159,013.63
Encircled energy fraction 0.82

Instrument name: STIS
Mode: spectroscopic
Detector: NUVMAMA
Central Wavelength:
Grating: [G230L] R ~ 500
Aperture: 52X2


Target: [point source]
Spectrum: Kurucz Models O9V 33000. 4.0
Extinction E(B-V): Milky Way Diffuse (Rv=3.1) = 0.25 applied before normalization
Normalization: Renormalized to vegamag = 11.85 in filter Johnson/U
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 24.2