Space Telescope Science Institute  F25QTZD1-FUV-MAMA, Longpass Pseudo-aperture F25SRF2D1-FUV-MAMA, Longpass Pseudo-aperture

F25SRF2-FUV-MAMA, Longpass

Description

The F25SRF2 filter with the FUV-MAMA provides high-throughput broad-band far-UV imaging with better rejection of geocoronal emission than the F25MAMA but worse than F25QTZ modes. It provides the same field of view and spatial resolution as these modes.

Recommended Uses

This filter has slightly higher throughput than F25QTZ, but lets in geocoronal OI 1302 Å. For sky-limited imaging F25QTZ is usually a better choice.

Special Considerations

Sky background on the day side of the orbit contains a significant contributions from OI air glow emission at 1356 Å and at 1302 Å. In high-background conditions, the sky background can dominate the detector background. In average day-side observing conditions the sky background through this filter will be about a factor of 100 higher than for F25QTZ. Observers can limit the background (with some cost to the total amount of observing time per orbit) by using the DARKTIME special requirement.

Users may also want to consider whether the ACS SBC detector might be better for their observing program.

Pivot (Å)
FWHM (Å)
AB mag zeropoint
Speak
B
R80 (arcsec)
Flux in central pixel
1457.4
283.7
22.825
8.67e+13
303.5
0.30
9%

Figure 14.83: F25SRF2 FUV-MAMA Integrated System Throughput and Redleak

 

Table 14.34: Throughput and Sensitivity for F25SRF2 FUV-MAMA
l
Sensitivity
Throughput %
1300.
7.18E13
2.42
1325.
8.60E13
2.85
1350.
8.66E13
2.82
1375.
8.53E13
2.72
1400.
8.30E13
2.60
1425.
7.82E13
2.41
1450.
7.27E13
2.20
1475.
6.69E13
1.99
1500.
6.07E13
1.78
1525.
5.47E13
1.58
1550.
4.90E13
1.39
1575.
4.30E13
1.20
1600.
3.73E13
1.02
1625.
3.25E13
0.88
1650.
2.84E13
0.76
1675.
2.43E13
0.64
1700.
1.99E13
0.51
1725.
1.68E13
0.43
1750.
1.42E13
0.36
1775.
1.19E13
0.29
1800.
9.96E12
0.24
Figure 14.84: Point Source S/N vs. V+AB for the F25SRF2 FUV-MAMA mode. Curves are labeled by required exposure time (sec).

 
Figure 14.85: Extended Source S/N vs. V+AB for the F25SRF2 FUV-MAMA mode. Top curves are for an area of 0.2 arcsec2; bottom curves are for 1 arcsec2. Average sky assumed. Curves are labeled by required exposure time (sec).

 

Table 14.35: Radial Profile for F25SRF2*
Radius

Fraction of Energy Encircled
Pixels
Arcsec
Intensity
1
0.024
3.544e-02
0.154
2
0.037
2.268e-02
0.256
2
0.049
1.408e-02
0.358
3
0.073
5.787e-03
0.493
4
0.098
2.765e-03
0.576
5
0.122
1.514e-03
0.630
10
0.245
3.098e-04
0.762
15
0.367
1.677e-04
0.847
20
0.490
8.854e-05
0.910
25
0.613
4.487e-05
0.954
30
0.735
2.080e-05
0.980
40
0.980
1.510e-06
0.999

* See STIS ISR 2003-01.

Figure 14.86: Point Source Encircled Energy for F25SRF2 FUV-MAMA

 
Figure 14.87: Point Source Intensity vs. Radius for F25SRF2 FUV-MAMA

 
F25QTZD1-FUV-MAMA, Longpass Pseudo-aperture F25SRF2D1-FUV-MAMA, Longpass Pseudo-aperture
Space Telescope Science Institute
http://www.stsci.edu
Voice: (410) 338-1082
help@stsci.edu