F25LYA - FUV-MAMA, Lyman-alpha
Description
The F25LYA filter with the FUV-MAMA provides narrowband imaging of the HI 1216 Å Lyman-α line.
Recommended Uses
This filter is recommended for imaging Lyman-α emission. Differencing two images taken with 25MAMA and F25SRF2 is another option.
Special Considerations
Sensitivity is limited by geocoronal Lyman-α. 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 with the F122M or F125LP filters might be a better choice for their observing program.
Pivot λ (Å) | FWHM (Å) | AB mag zero point | Speak | Bλ | R80 (arcsec) | Flux in central pixel |
1242.8 | 141.2 | 19.470 | 8.76e+12 | 99.5 | 0.35 | 6% |
Figure 14.88: F25LYA FUV-MAMA Integrated System Throughput and Redleak
Table 14.36: F25LYA FUV-MAMA Sensitivity & Throughput
λ | Sensitivity | % Throughput |
1150. | 5.06E11 | 0.02 |
1175. | 3.42E12 | 0.13 |
1200. | 7.42E12 | 0.27 |
1225. | 8.15E12 | 0.29 |
1250. | 5.62E12 | 0.20 |
1275. | 3.40E12 | 0.12 |
1300. | 2.05E12 | 0.07 |
1325. | 1.27E12 | 0.04 |
1350. | 8.13E11 | 0.03 |
1375. | 5.62E11 | 0.02 |
Figure 14.89: Point Source S/N vs. flux for the F25LYA FUV-MAMA mode. Curves are labeled by required exposure time (seconds).
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. Curves are labeled by required exposure time (seconds).
Table 14.37: Radial Profile for F25LYA*
Radius | Fraction of Energy Encircled | ||
Pixels | Arcsec | Intensity | |
1 | 0.024 | 2.440e-02 | 0.100 |
1.5 | 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 |
* See STIS ISR 2003-01.
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
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STIS Instrument Handbook
- • Acknowledgments
- Chapter 1: Introduction
-
Chapter 2: Special Considerations for Cycle 33
- • 2.1 Impacts of Reduced Gyro Mode on Planning Observations
- • 2.2 STIS Performance Changes Pre- and Post-SM4
- • 2.3 New Capabilities for Cycle 33
- • 2.4 Use of Available-but-Unsupported Capabilities
- • 2.5 Choosing Between COS and STIS
- • 2.6 Scheduling Efficiency and Visit Orbit Limits
- • 2.7 MAMA Scheduling Policies
- • 2.8 Prime and Parallel Observing: MAMA Bright-Object Constraints
- • 2.9 STIS Snapshot Program Policies
- Chapter 3: STIS Capabilities, Design, Operations, and Observations
- Chapter 4: Spectroscopy
- Chapter 5: Imaging
- Chapter 6: Exposure Time Calculations
- Chapter 7: Feasibility and Detector Performance
-
Chapter 8: Target Acquisition
- • 8.1 Introduction
- • 8.2 STIS Onboard CCD Target Acquisitions - ACQ
- • 8.3 Onboard Target Acquisition Peakups - ACQ PEAK
- • 8.4 Determining Coordinates in the International Celestial Reference System (ICRS) Reference Frame
- • 8.5 Acquisition Examples
- • 8.6 STIS Post-Observation Target Acquisition Analysis
- Chapter 9: Overheads and Orbit-Time Determination
- Chapter 10: Summary and Checklist
- Chapter 11: Data Taking
-
Chapter 12: Special Uses of STIS
- • 12.1 Slitless First-Order Spectroscopy
- • 12.2 Long-Slit Echelle Spectroscopy
- • 12.3 Time-Resolved Observations
- • 12.4 Observing Too-Bright Objects with STIS
- • 12.5 High Signal-to-Noise Ratio Observations
- • 12.6 Improving the Sampling of the Line Spread Function
- • 12.7 Considerations for Observing Planetary Targets
- • 12.8 Special Considerations for Extended Targets
- • 12.9 Parallel Observing with STIS
- • 12.10 Coronagraphic Spectroscopy
- • 12.11 Coronagraphic Imaging - 50CORON
- • 12.12 Spatial Scans with the STIS CCD
-
Chapter 13: Spectroscopic Reference Material
- • 13.1 Introduction
- • 13.2 Using the Information in this Chapter
-
13.3 Gratings
- • First-Order Grating G750L
- • First-Order Grating G750M
- • First-Order Grating G430L
- • First-Order Grating G430M
- • First-Order Grating G230LB
- • Comparison of G230LB and G230L
- • First-Order Grating G230MB
- • Comparison of G230MB and G230M
- • First-Order Grating G230L
- • First-Order Grating G230M
- • First-Order Grating G140L
- • First-Order Grating G140M
- • Echelle Grating E230M
- • Echelle Grating E230H
- • Echelle Grating E140M
- • Echelle Grating E140H
- • PRISM
- • PRISM Wavelength Relationship
-
13.4 Apertures
- • 52X0.05 Aperture
- • 52X0.05E1 and 52X0.05D1 Pseudo-Apertures
- • 52X0.1 Aperture
- • 52X0.1E1 and 52X0.1D1 Pseudo-Apertures
- • 52X0.2 Aperture
- • 52X0.2E1, 52X0.2E2, and 52X0.2D1 Pseudo-Apertures
- • 52X0.5 Aperture
- • 52X0.5E1, 52X0.5E2, and 52X0.5D1 Pseudo-Apertures
- • 52X2 Aperture
- • 52X2E1, 52X2E2, and 52X2D1 Pseudo-Apertures
- • 52X0.2F1 Aperture
- • 0.2X0.06 Aperture
- • 0.2X0.2 Aperture
- • 0.2X0.09 Aperture
- • 6X0.2 Aperture
- • 0.1X0.03 Aperture
- • FP-SPLIT Slits 0.2X0.06FP(A-E) Apertures
- • FP-SPLIT Slits 0.2X0.2FP(A-E) Apertures
- • 31X0.05ND(A-C) Apertures
- • 0.2X0.05ND Aperture
- • 0.3X0.05ND Aperture
- • F25NDQ Aperture
- 13.5 Spatial Profiles
- 13.6 Line Spread Functions
- • 13.7 Spectral Purity, Order Confusion, and Peculiarities
- • 13.8 MAMA Spectroscopic Bright Object Limits
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Chapter 14: Imaging Reference Material
- • 14.1 Introduction
- • 14.2 Using the Information in this Chapter
- 14.3 CCD
- 14.4 NUV-MAMA
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14.5 FUV-MAMA
- • 25MAMA - FUV-MAMA, Clear
- • 25MAMAD1 - FUV-MAMA Pseudo-Aperture
- • F25ND3 - FUV-MAMA
- • F25ND5 - FUV-MAMA
- • F25NDQ - FUV-MAMA
- • F25QTZ - FUV-MAMA, Longpass
- • F25QTZD1 - FUV-MAMA, Longpass Pseudo-Aperture
- • F25SRF2 - FUV-MAMA, Longpass
- • F25SRF2D1 - FUV-MAMA, Longpass Pseudo-Aperture
- • F25LYA - FUV-MAMA, Lyman-alpha
- • 14.6 Image Mode Geometric Distortion
- • 14.7 Spatial Dependence of the STIS PSF
- • 14.8 MAMA Imaging Bright Object Limits
- Chapter 15: Overview of Pipeline Calibration
- Chapter 16: Accuracies
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Chapter 17: Calibration Status and Plans
- • 17.1 Introduction
- • 17.2 Ground Testing and Calibration
- • 17.3 STIS Installation and Verification (SMOV2)
- • 17.4 Cycle 7 Calibration
- • 17.5 Cycle 8 Calibration
- • 17.6 Cycle 9 Calibration
- • 17.7 Cycle 10 Calibration
- • 17.8 Cycle 11 Calibration
- • 17.9 Cycle 12 Calibration
- • 17.10 SM4 and SMOV4 Calibration
- • 17.11 Cycle 17 Calibration Plan
- • 17.12 Cycle 18 Calibration Plan
- • 17.13 Cycle 19 Calibration Plan
- • 17.14 Cycle 20 Calibration Plan
- • 17.15 Cycle 21 Calibration Plan
- • 17.16 Cycle 22 Calibration Plan
- • 17.17 Cycle 23 Calibration Plan
- • 17.18 Cycle 24 Calibration Plan
- • 17.19 Cycle 25 Calibration Plan
- • 17.20 Cycle 26 Calibration Plan
- • 17.21 Cycle 27 Calibration Plan
- • 17.22 Cycle 28 Calibration Plan
- • 17.23 Cycle 29 Calibration Plan
- • 17.24 Cycle 30 Calibration Plan
- • 17.25 Cycle 31 Calibration Plan
- • 17.26 Cycle 32 Calibration Plan
- Appendix A: Available-But-Unsupported Spectroscopic Capabilities
- • Glossary