F25LYA-FUV-MAMA, Lyman-alpha
Description
The F25LYA filter with the FUV-MAMA provides narrowband imaging of the HI 1216 Å Lyman-
line.
Recommended Uses
Lyman- imaging. Differencing two images taken with 25MAMA and F25SRF2 is another option.
Special Considerations
Sensitivity is limited by geocoronal Lyman-. Observers can limit the background (with some cost to the total amount of observing time per orbit) by using the DARKTIME special requirement.
Pivot  (Å) |
FWHM (Å) |
AB mag zeropoint |
Speak |
B |
R80 (arcsec) |
Flux in central pixel |
| 1243.1 |
145.4 |
19.569 |
9.44e+12 |
101.1 |
0.35 |
6% |
Figure 14.88: F25LYA FUV-MAMA Integrated System Throughput and Redleak
Table 14.35: Throughput and Sensitivity for F25LYA FUV-MAMA
| l |
Sensitivity |
Throughput % |
| 1150. |
6.01E11 |
0.02 |
| 1175. |
3.91E12 |
0.15 |
| 1200. |
8.37E12 |
0.31 |
| 1225. |
8.94E12 |
0.32 |
| 1250. |
5.95E12 |
0.21 |
| 1275. |
3.60E12 |
0.12 |
| 1300. |
2.19E12 |
0.07 |
| 1325. |
1.37E12 |
0.05 |
| 1350. |
8.90E11 |
0.03 |
| 1375. |
6.26E11 |
0.02 |
Figure 14.89: Point Source S/N vs. flux for the F25LYA FUV-MAMA mode.
Figure 14.90: Extended Source S/N vs. flux for the F25LYA FUV-MAMA mode. Top curves are for an area of 0.2 arcsec2; bottom curves are for 1 arcsec2. Average sky assumed.
Table 14.36: Radial Profile for F25LYA
| Radius |
|
Fraction of Energy Encircled |
| Pix |
arcsec |
intensity |
| 1 |
0.024 |
2.440e-02 |
0.100 |
| 2 |
0.037 |
1.702e-02 |
0.174 |
| 2 |
0.049 |
1.199e-02 |
0.254 |
| 3 |
0.073 |
6.423e-03 |
0.387 |
| 4 |
0.098 |
3.326e-03 |
0.485 |
| 5 |
0.122 |
1.718e-03 |
0.549 |
| 10 |
0.245 |
3.888e-04 |
0.712 |
| 15 |
0.367 |
2.140e-04 |
0.816 |
| 20 |
0.490 |
1.044e-04 |
0.895 |
| 25 |
0.613 |
4.910e-05 |
0.943 |
| 30 |
0.735 |
1.741e-05 |
0.968 |
| 40 |
0.980 |
8.124e-06 |
0.994 |
Figure 14.91: Point Source PSF for F25LYA FUV-MAMA, 7."5 square (at pixel 739, 368, log scaled, B-V=-0.04)
Figure 14.92: Point Source Encircled Energy for F25LYA FUV-MAMA
Figure 14.93: Point Source Intensity vs. Radius for F25LYA FUV-MAMA
