A.2 Full Aperture Complement

The STIS aperture wheel has 65 positions, several of which correspond to multiple slits or masks. Only a small fraction of the full complement of spectroscopic apertures is currently supported. Table A.1 and Table A.2 provide complete lists of STIS apertures for spectroscopy, together with comments regarding their characteristics or purposes. For most apertures, the aperture name gives the length in the spatial direction by the width in the dispersion direction in arcseconds. Schematics of three complex apertures are given in Figure A.1, Figure A.2, and Figure A.3.

Note that all set-ups with the NUV-PRISM are available-but-unsupported starting Cycle 30.

Table A.1: STIS Spectroscopic Apertures. Supported apertures are in boldface.

Apertures that can be used with the Echelle Gratings
Apertures	Comments
`0.1X0.03 0.1X0.06 0.1X0.09 0.1X0.2`	The latter two are supported with `E230H` only. The `0.1X0.03` is supported with all echelle gratings.
`0.2X0.06 0.2X0.09 0.2X0.2 0.2X0.5`	`0.2X0.2` is supported with all echelle modes, while `0.2X0.09` is supported with `E230H` and `E140H`, and `0.2X0.06` is only supported on `E230H`
`0.2X0.06FP 0.2X0.2FP`	Masks with five apertures, suffixed A through E, for reduction of fixed-pattern noise; see Figure A.3.
`0.2X0.05ND 0.3X0.05ND`	Neutral-density slits. Dex ND factors are 2.0 and 3.0, respectively.
`0.3X0.06 0.3X0.09 0.3X0.2 0.5X0.5 1X0.06 1X0.2`	Miscellaneous available-but-unsupported echelle apertures.
`2X2 6X0.06 6X0.2 6X0.5 6X6`	The `6X0.2` long slit is supported with the echelles.
`52X0.05 52X0.1 52X0.2 52x0.5 52X2`	Long slits for use with the echelles. `52X0.05` is supported, and the others are available-but-unsupported with the echelle gratings.
`52X0.05F1 52X0.05F2 52X0.1F1 52X0.1F2 52X0.2F1 52X0.2F2 52X0.5F1 52X0.5F2 52X2F1 52X2F2`	The fiducial bar slits are available-but-unsupported with the echelle gratings.
`52X0.1B0.5 52x0.1B1.0 52x0.1B3.0`	A long slit with 3 fiducial bars. The bar length in arcseconds is given by the third dimension. See Figure A.1.
`31X0.05NDA 31X0.05NDB 31X0.05NDC`	Neutral-density-filtered long slits, which may be used for bright objects. The dex ND factors are 0.4, 0.8, and 1.2, respectively.
`25MAMA`	Full-field clear aperture.
`F25QTZ F25SRF2`	Supported long-pass filters, with all echelles.
`F25ND3 F25ND5 F25NDQ1 F25NDQ2 F25NDQ3 F25NDQ4`	Supported neutral-density filters for MAMA detectors.The numbers give the dex ND factors.
`F25MGII F25CN270 F25CIII F25CN182`	Narrow-band filters. `F25MGII` is supported for `E230H` and E230M. Others are available with the NUV-MAMA only.
`F25LYA`	Available-but-unsupported with the FUV-MAMA only.
`36X0.05P45 36X0.05N45 36X0.6P45 36X0.6N45`	Long slits which are inclined at ±45° to facilitate observations of moving targets at off-nominal rolls. See Figure A.2.

Table A.2: STIS Spectroscopic Apertures. Supported apertures are in boldface.

Apertures that can be used with the First-Order Gratings
Apertures	Comments
`52X0.05 52X0.1 52X0.2 52X0.5 52X2`	Long slits.
`52X0.05E1 52X0.1E1 52X0.2E1 52X0.5E1 52X2E1`	Long slits centered at 19.7 arcseconds in +Y position. (Places compact target at row ~900 on the CCD to reduce CTE losses.). Supported with all CCD gratings. Use with the MAMAs is not allowed.
`52X0.2E2 52X0.5E2 52X2E2`	These CTE aperture positions are centered near row 900 on the STIS CCD detector; however, the positions are offset from the physical aperture centers to give better alignment with fringe flats done using the `52X0.1` aperture. The E2 positions are supported for the `G750L` and `G750M` gratings only.
`52X0.05D1 52X0.1D1 52X0.2D1 52X0.5D1 52X2D1`	These aperture positions put a target near the bottom edge of the FUV-MAMA and are intended for observation of very faint targets where it is necessary to minimize the contribution of the FUV-MAMA dark current. They are all supported with the `G140L` and `G140M` gratings. `52X0.05D1` and `52X0.1D1` are also supported for CCD peakups.
`52X0.05F1 52X0.05F2 52X0.1F1 52X0.1F2 52X0.2F1 52X0.2F2 52X0.5F1 52X0.5F2 52X2F1 52X2F2`	Fiducial bars on the long slits which can be used for coronagraphic spectroscopy. The `52X0.2F1` is supported for all first-order gratings and is available-but-unsupported for the `PRISM`. The other fiducial bars are available-but-unsupported with all gratings and the `PRISM`. The F1 and F2 bars are 0.5 arcseconds and 0.86 arcseconds long, respectively (see Figure 13.1).
`52X0.1B0.5 52X0.1B1.0 52X0.1B3.0`	A long slit with 3 fiducial bars where the bar length in arcseconds is given by the third dimension. See Figure A.1.
`31X0.05NDA 31X0.05NDB 31X0.05NDC`	Neutral-density-filtered long slits of the given dimensions in arcseconds, which may be used for bright objects or flat-field calibration. The dex ND factors are 0.4, 0.8, and 1.2, respectively. Use with the NUV-PRISM is “available-but-unsupported.”
`0.5x0.5 2X2 6X6`	Square apertures of the given dimensions in arcsec.
`0.1X0.03 0.1X0.06 0.1X0.09 0.1X0.2 0.2X0.06 0.2X0.09 0.2X0.2 0.2X0.5 0.3X0.06 0.3X0.09 0.3X0.2 1X0.06 1X0.2 6X0.06 6X0.2 6X0.5 0.2X0.05ND 0.3X0.05ND`	As of Cycle 12, the `0.2X0.2` aperture is supported for use with all first-order gratings; it is available-but-unsupported with the PRISM. While not supported for first-order observations, the other echelle apertures can be used in first order as available-but-unsupported apertures. This includes the echelle neutral-density slits `0.2X0.05ND` and `0.3X0.05ND` with dex ND factors of 2.0 and 3.0, respectively.
`25MAMA 50CCD`	Supported full-field clear apertures.
`F25QTZ F25SRF2`	`F25QTZ` and `F25SRF2` are supported for all MAMA gratings, but are unavailable with the CCD and no longer supported for `PRISM`.
`25MAMAD1 F25SRF2D1 F25QTZD1`	These aperture positions put a target near the bottom edge of the FUV-MAMA and are intended for observation of very faint targets where it is necessary to minimize the contribution of the FUV-MAMA dark current. They are all supported with the `G140L` and `G140M` gratings.
`F25ND3 F25ND5 F25NDQ1 F25NDQ2 F25NDQ3 F25NDQ4`	Supported neutral-density filters for MAMA detectors. Can be used as available-but-unsupported apertures with the CCD gratings. The numbers give the dex ND factors.
`F25MGII F25CN270 F25CIII F25CN182`	`F25MGII` is supported and these other filters are available-but-unsupported with the NUV-MAMA gratings and `PRISM` only.
`F25LYA`	The `F25LYA` filter is available-but-unsupported with the `G140L`, `G140M`, `E140H`, and `E140M` gratings only.
`F28X50LP F28X50OII F28X50OIII`	These CCD imaging filters are available-but-unsupported with the CCD gratings, but are unavailable with the MAMA detectors.
`36X0.05P45 36X0.05N45 36X0.6P45 36X0.6N45`	Long slits of given dimensions in arcseconds, inclined at ±45° to facilitate observations of moving targets at off-nominal rolls. See Figure A.1.

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STIS Instrument Handbook
- • Acknowledgments
- Chapter 1: Introduction
  - • 1.1 Overview
  - • 1.2 Introduction to the Handbook
  - • 1.3 Handbook Layout
  - • 1.4 Proposal Preparations and Observations with STIS
  - • 1.5 The Help Desk at STScI
  - • 1.6 The STIS Web Pages and Support Information
  - • 1.7 Non-proprietary STIS Data
- Chapter 2: Special Considerations for Cycle 32
  - • 2.1 STIS Repair and Return to Operations
  - • 2.2 Summary of STIS Performance Changes Since 2004
  - • 2.3 New Capabilities for Cycle 32
  - • 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
  - • 3.1 Instrument Capabilities
  - • 3.2 Instrument Design
  - • 3.3 Basic Instrument Operations
  - • 3.4 Designing STIS Observations
- Chapter 4: Spectroscopy
  - • 4.1 Overview
  - • 4.2 First-Order Long-Slit Spectroscopy
  - • 4.3 Echelle Spectroscopy in the Ultraviolet
  - • 4.4 Objective Prism Spectroscopy
- Chapter 5: Imaging
  - • 5.1 Imaging Overview
  - • 5.2 Optical CCD Imaging
  - • 5.3 Ultraviolet Imaging with the MAMA Detectors
  - • 5.4 Neutral Density Filters
- Chapter 6: Exposure Time Calculations
  - • 6.1 Overview
  - • 6.2 Determining Count Rates from Sensitivities
  - • 6.3 Throughput and Sensitivity
  - • 6.4 Computing Exposure Times
  - • 6.5 Detector and Sky Backgrounds
  - • 6.6 Tabular Sky Backgrounds
  - • 6.7 Extinction Correction
  - • 6.8 Exposure Time Examples
- Chapter 7: Feasibility and Detector Performance
  - • 7.1 STIS Detectors
  - • 7.2 The CCD
  - • 7.3 CCD Operation and Feasibility Considerations
  - • 7.4 The MAMA Detectors
  - • 7.5 MAMA Operation and Feasibility Considerations
  - • 7.6 MAMA Spectral and Spatial Offsetting
  - • 7.7 MAMA Bright Object Limits
- 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
  - • 9.1 Overview
  - • 9.2 STIS Exposure Overheads
  - • 9.3 Orbit Use Determination Examples
- Chapter 10: Summary and Checklist
  - • 10.1 Phase I Proposing
  - • 10.2 Phase II - Scheduling Approved Observations
- Chapter 11: Data Taking
  - • 11.1 Basic Operating Modes
  - • 11.2 Exposure Sequences and Contemporaneous Calibrations
  - • 11.3 Patterns and Dithering
  - • 11.4 Fixing Orientation on the Sky
  - • 11.5 Target Positioning
- 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
    - • First-Order Spatial Profiles
    - • Echelle Spatial Profiles
  - 13.6 Line Spread Functions
    - • First-Order Line Spread Functions
    - • Echelle Line Spread Functions
  - • 13.7 Spectral Purity, Order Confusion, and Peculiarities
  - • 13.8 MAMA Spectroscopic Bright Object Limits
- Chapter 14: Imaging Reference Material
  - • 14.1 Introduction
  - • 14.2 Using the Information in this Chapter
  - 14.3 CCD
    - • CCD Clear Imaging - 50CCD
    - • CCD Long-Pass Imaging F28X50LP
    - • F28X50OIII - CCD
    - • F28X50OII - CCD
    - • 50CORON - Clear CCD
  - 14.4 NUV-MAMA
    - • 25MAMA - NUV-MAMA, Clear
    - • F25ND3 - NUV-MAMA
    - • F25ND5 - NUV-MAMA
    - • F25NDQ - NUV-MAMA
    - • F25QTZ - NUV-MAMA, Longpass
    - • F25SRF2 - NUV-MAMA, Longpass
    - • F25MGII - NUV-MAMA
    - • F25CN270 - NUV-MAMA
    - • F25CIII - NUV-MAMA
    - • F25CN182 - NUV-MAMA
  - 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
  - • 15.1 Pipeline Processing Overview
  - • 15.2 How Phase II Parameter Choices Affect Calibration
  - • 15.3 More Detailed Information
- Chapter 16: Accuracies
  - • 16.1 Summary of Accuracies
- 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
- Appendix A: Available-But-Unsupported Spectroscopic Capabilities
  - • A.1 Introduction
  - • A.2 Full Aperture Complement
  - • A.3: Additional Available-but-Unsupported Options
- • Glossary

A.2 Full Aperture Complement

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