ETC Request ID: STIS.sp.1038404

Exposure time (seconds) = 2,156.0000 at wavelength 2026.00 Å

gives: SNR = 134.2429 (per resolution element)

Exposure time calculation HAD WARNINGS.

WARNING MESSAGE: MAMA Bright limits: total count rate per image 135802 exceeds limit for irregularly-variable sources 40 percent of the bright limit 200000 counts per second

WARNING MESSAGE: Buffer time 14.7273 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 4.569 19,702.51 140.37
    Background 0.011 45.28 6.73
        Sky 1.057e-11 4.56e-08 2.13e-04
        Dark Current 0.011 45.28 6.73
Total in selected region 4.580 19,747.78 146.77
Brightest Pixel (single exposure) (at 2319.47 Å) 3.689 7,954.41
Count rate entire detector 135,802.478
Buffer Time (sec) 14.73
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 105,692.661 227,873,378.110
    Background (sky+dark) 1,572.864 3,391,094.99
Encircled energy fraction 0.93

Instrument name: STIS
Mode: spectroscopic
Detector: NUVMAMA
Central Wavelength: 1978
Grating: [E230M] R ~ 30000
Aperture: 31X0.05NDB


Target: [point source]
Spectrum: Castelli-Kurucz Models B0III 29000 3.5
Extinction E(B-V): Milky Way Diffuse (Rv=3.1) = 0.25 applied before normalization
Normalization: Renormalized to vegamag = 5.51 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