ETC Request ID: STIS.sp.1005542

Exposure time (seconds) = 200.0000 at wavelength 2790.00 Å

gives: SNR = 38.2696 (per resolution element)

Exposure time calculation HAD WARNINGS.

WARNING MESSAGE: MAMA Bright limits: total count rate per image 137253 exceeds limit for irregularly-variable sources 40 percent of the bright limit 200000 counts per second

WARNING MESSAGE: Buffer time 14.5717 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 3.772 1,508.89 38.84
    Background 0.011 4.20 2.05
        Sky 1.917e-10 7.67e-08 2.77e-04
        Dark Current 0.011 4.20 2.05
Total in selected region 3.783 1,513.09 39.43
Brightest Pixel (single exposure) (at 2652.66 Å) 2.335 467.06
Count rate entire detector 137,252.508
Buffer Time (sec) 14.57
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 118,187.940 23,637,587.982
    Background (sky+dark) 1,572.864 314,572.80
Encircled energy fraction 0.93

Instrument name: STIS
Mode: spectroscopic
Detector: NUVMAMA
Central Wavelength: 2762
Grating: [E230H] R ~ 114000
Aperture: 0.1X0.03


Target: [point source]
Spectrum: Castelli-Kurucz Models A3V 8750 4.0
Extinction E(B-V): None
Normalization: Renormalized to vegamag = 4.45 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