This file is intended as documentation of the Field(s) Of View (FOV(s)) for the detectors and/or slits and/or apertures comprising the instrument on the New Horizons (NH) spacecraft that generated the data archived in this data set. This file is a NH Project RALPH SPICE Instrument Kernel (IK), current at the time of delivery of this data set. It is only provided as a convenience to the user to visualize the FOVs of the instrument. This file will not be updated in this PDS data set as part of any SPICE kernel updates, and should therefore not be used as a SPICE kernel in any scientific investigation. Specifically, the references in the IK are not relevant to the graphic visualization of the FOV and will not be provided with this data set or archived elsewhere; therefore the references should be ignored in the context of the intended scope of this file as described above. As a SPICE IK, this file has much more information than just the FOV description (e.g. references to project documentation), but in the context of this PDS data set only the FOV description is relevant. For a more complete understanding of the geometry and timing issues of the New Horizons mission, the user is directed to the SPICE PDS data set for the mission, with a data set ID of NH-J/P/SS-SPICE-6-V1.0. CAVEATS: This file is the NH RALPH SPICE Instrument Kernel (IK), current at the time of delivery of this data set. It is only provided as a convenience to the user to visualize the FOVs of the instrument. This file will not be updated in this PDS data set as part of any SPICE kernel updates, and should therefore not be used as a SPICE kernel in any scientific investigation. Specifically, the references in the IK are not relevant to the graphic visualization of the FOV and will not be provided with this data set; therefore the references should be ignored in the context of this file. If the user wishes to do any data analysis requiring NAIF/SPICE IKs, they should not use this file, but rather get the most recent IK from the NH SPICE data set and use that. - This file is included in document collection for this instrument as a convenience to the user because, in some of its sections, it documents the geometry of the MVIC instrument Field(s) Of View (FOV(s)). Other sections of this IK (e.g. the references) will have limited use in that scope. - The original name of the source of this file was NH_RALPH_V###.TI where ### is a version number. - The format of this file, starting five lines after this description, is a SPICE Kernel Pool text file - The Instrument Kernel itself is (or will be) formally archived with the New Horizons SPICE dataset. - See the SPICE documentation for details of that format - http://naif.jpl.nasa.gov/ - Even without understanding that format, the Instrument Kernel, and especially its comments, are human readable. Comments are any line for which one of the following three statements is true: 1) The line is before the first data marker line in the file 2) The line is in a section of lines between a text marker line and a data marker line with no intervening text or data marker lines 3) The line is in a section of lines between the last text marker and the end of the file with no intervening text or data marker lines - a data marker line has the single token '\begindata' on it with all other characters on the line being whitespace - a text marker line has the single token '\begintext' on it with all other characters on the line being whitespace - N.B. Because padding and a carriage return have been added to each line of this file, it may or may not be functional as a valid SPICE kernel. ######################################################################## ##################### SPICE IK Starts after next line ################## ######################################################################## KPL/IK RALPH Instrument Kernel ============================================================================== This instrument kernel (I-kernel) contains references to the mounting alignment, internal and FOV geometry for the New Horizons Visible/IR integrated imaging and spectroscopy remote sensing package (RALPH). Version and Date ---------------------------------------------------------- The TEXT_KERNEL_ID stores version information of loaded project text kernels. Each entry associated with the keyword is a string that consists of four parts: the kernel name, version, entry date, and type. For example, the RALPH I-kernel might have an entry as follows: TEXT_KERNEL_ID += 'NEWHORIZONS_RALPH V1.0.0 22-FEBRUARY-2007 IK' | | | | | | | | KERNEL NAME <-------+ | | | | | V VERSION <-------+ | KERNEL TYPE | V ENTRY DATE RALPH I-Kernel Version: \begindata TEXT_KERNEL_ID += 'NEWHORIZONS_RALPH V1.0.0 22-FEBRUARY-2007 IK' NAIF_BODY_NAME += ( 'NH_RALPH' ) NAIF_BODY_CODE += ( -98200 ) NAIF_BODY_NAME += ( 'NH_RALPH_MVIC_FT' ) NAIF_BODY_CODE += ( -98203 ) NAIF_BODY_NAME += ( 'NH_RALPH_MVIC_PAN2' ) NAIF_BODY_CODE += ( -98204 ) NAIF_BODY_NAME += ( 'NH_RALPH_MVIC_PAN1' ) NAIF_BODY_CODE += ( -98205 ) NAIF_BODY_NAME += ( 'NH_RALPH_MVIC_RED' ) NAIF_BODY_CODE += ( -98206 ) NAIF_BODY_NAME += ( 'NH_RALPH_MVIC_BLUE' ) NAIF_BODY_CODE += ( -98207 ) NAIF_BODY_NAME += ( 'NH_RALPH_MVIC_METHANE' ) NAIF_BODY_CODE += ( -98208 ) NAIF_BODY_NAME += ( 'NH_RALPH_MVIC_NIR' ) NAIF_BODY_CODE += ( -98209 ) NAIF_BODY_NAME += ( 'NH_RALPH_LEISA' ) NAIF_BODY_CODE += ( -98201 ) NAIF_BODY_NAME += ( 'NH_RALPH_SIA' ) NAIF_BODY_CODE += ( -98202 ) \begintext Version 1.0.0 -- February 22, 2007 -- Lillian Nguyen, JHU/APL -- Removed the NH_RALPH_MVIC field of view definition and added a NH_RALPH instrument boresight. -- Removed the NH_RALPH_MVIC pixel size and IFOV definitions and replaced them with the identical definitions for each of the MVIC arrays. -- Promoting to version 1.0.0 denoting approval of kernel set by instrument teams. Version 0.0.3 -- February 13, 2007 -- Lillian Nguyen, JHU/APL -- Updated the MVIC FOV, LEISA FOV, and LEISA IFOV. -- Added fields of view for the Frame Transfer and TDI arrays. Version 0.0.2 -- October 4, 2006 -- Lillian Nguyen, JHU/APL -- Removed the 3-letter frames NH_MVI, NH_LEI. Version 0.0.1 -- June 15, 2006 -- Lillian Nguyen -- Pixel size and IFOV added for MVIC and LEISA. Version 0.0.0 -- December 28, 2005 -- Lillian Nguyen -- Draft Version. NOT YET APPROVED BY INSTRUMENT TEAM. References ---------------------------------------------------------- 1. Slides from Ralph Instrument Acceptance Review, April 13, 2005. 2. ``Kernel Pool Required Reading'' 3. New Horizons Spacecraft to PERSI/RALPH Interface Control Document, Rev B, 7399-9201. 4. APL New Horizons web site, http://pluto.jhuapl.edu/spacecraft/overview.html. 5. New Horizons Spacecraft Frames Kernel. 6. New Horizons Mission Science Definitions (MSD), NH7399-9000v1.6. 7. RALPH Mechanical Interface Control Drawing (MICD), Rev B, 574995_b. 8. ALICE Instrument Kernel. 9. Ralph Instrument Specification, Rev. A ECR SWRI 5310-001. 10. LEISA to Ralph Interface Control Document. 11. Document titled "RalphArrayPositions.doc", received from Cathy Olkin by e-mail, Mar. 23, 2006, and e-mail exchange concerning the document, Apr. 3-4, 2006. 12. "RalphAlignWriteup03.doc", received from Allen Lunsford 2/7/2007. 13. E-mail from Cathy Olkin regarding the removal of the NH_RALPH_MVIC frame and the introduction of the NH_RALPH frame, received 2/22/2007. Contact Information ---------------------------------------------------------- Lillian Nguyen, JHU/APL, (443)-778-5477, Lillian.Nguyen@jhuapl.edu Implementation Notes ---------------------------------------------------------- This file is used by the SPICE system as follows: programs that make use of this instrument kernel must ``load'' the kernel, normally during program initialization. Loading the kernel associates data items with their names in a data structure called the ``kernel pool''. The SPICELIB routine FURNSH, CSPICE routine furnsh_c, and IDL routine cspice_furnsh load SPICE kernels as shown below: FORTRAN (SPICELIB) CALL FURNSH ( 'kernel_name' ) C (CSPICE) furnsh_c ( "kernel_name" ) ICY (IDL) cspice_furnsh, 'kernel_name' In order for a program or subroutine to extract data from the pool, the SPICELIB routines GDPOOL, GCPOOL, and GIPOOL are used. See [2] for details. This file was created and may be updated with a text editor or word processor. Naming Conventions ---------------------------------------------------------- All names referencing values in this I-kernel start with the characters `INS' followed by the NAIF New Horizons spacecraft ID number (-98) followed by a NAIF three digit ID code for the RALPH instrument. The remainder of the name is an underscore character followed by the unique name of the data item. For example, the Ralph boresight direction in the Ralph frame (``NH_RALPH'' -- see [5] ) is specified by: INS-98200_BORESIGHT The upper bound on the length of the name of any data item is 32 characters. If the same item is included in more than one file, or if the same item appears more than once within a single file, the latest value supersedes any earlier values. RALPH description ---------------------------------------------------------- From [4]: ``Ralph: Visible and infrared imager/spectrometer; provides color, composition and thermal maps. . . . Ralph's main objectives are to obtain high resolution color maps and surface composition maps of the surfaces of Pluto and Charon. The instrument has two separate channels: the Multispectral Visible Imaging Camera (MVIC) and the Linear Etalon Imaging Spectral Array (LEISA). A single telescope with a 3-inch (6-centimeter) aperture collects and focuses the light used in both channels. MVIC operates at visible wavelengths - using the same light by which we see - and has 4 different filters for producing color maps. One filter is tailored to measure the methane frost distribution over the surface, while the others are more generic and cover blue, red and near-infrared colors, respectively. MVIC also has two panchromatic filters, which pass essentially all visible light, for when maximum sensitivity to faint light levels is required. In all cases, the light passes from the telescope through the filters and is focused onto a charge coupled device (CCD). (Although the MVIC CCD is a unique, sophisticated device, virtually all consumer digital cameras use CCDs.) LEISA operates at infrared wavelengths (it uses heat radiation), and its etalon acts like a prism to bend different wavelengths of light by different amounts so that each wavelength can be analyzed separately. Since quantum physics teaches us that different molecules emit and absorb light at different wavelengths, analysis of the different components of the light by LEISA can be used to identify the unique "fingerprints" of these molecules. LEISA will be used to map the distribution of frosts of methane (CH4), molecular nitrogen (N2), carbon monoxide (CO), and water (H2O) over the surface of Pluto and the water frost distribution over the surface of Charon. LEISA data may also reveal new constituents on the surfaces that have not yet been detected.'' From [10]: ``Ralph is a visible and infrared remote sensing camera comprised of MVIC and LEISA. MVIC is the multispectral visible imaging camera. LEISA is the infrared spectral imaging focal plane. The Ralph common telescope is based on a standard off-axis three mirror anastigmat design, which directs the image to a beamsplitter, sending the image to both the MVIC detector and LEISA. . . . The Ralph telescope is an all aluminum three-mirror "anastigmat" telescope. It has a 75 mm aperture and a 650 mm effective focal length when at its operating temperature of 220 K, or -53 degrees C. Its large, flat focal plane is shared by a beamsplitter that transmits the infrared light to the LEISA detector, while reflecting the visible and near-IR light to the MVIC detector. The field of view is 5.7 by 0.9 degrees for the visible, and 0.91 degrees square for the IR. The mirrors are to be made of aluminum, diamond turned, with uncoated aluminum surfaces.'' From [9]: ``MVIC shall provide imaging science data in five spectral bands at visible and near-infrared wavelengths. MVIC shall also provide Optical Navigation (OPNAV) imaging data for spacecraft navigation and orientation. The LEISA instrument shall provide high spectral resolution imaging science data at short-wave infrared wavelengths. MVIC will use optical filters to provide spectral band discrimination. LEISA will use a linear variable etalon filter to provide spectral discrimination. MVIC and the LEISA instrument shall use a common light collection telescope. The common telescope shall use a beamsplitter to direct light into two individual optical paths for the MVIC and LEISA detectors. MVIC shall obtain two dimensional science imaging data using time-delayed integration (TDI) data acquisition synchronized to one dimensional spacecraft rotation. MVIC will also obtain science imaging data using frame transfer data acquisition. The LEISA instrument shall obtain two-dimensional imaging data in push broom mode. MVIC shall use optical filters to provide the spectral band discrimination. MVIC shall have five spectral bands, for data obtained using TDI data acquisition, with wavelength ranges as described in Table 1 [reproduced below]. --------------- ------------------------------ Spectral Band Nominal Wavelength Range (nm) --------------- ------------------------------ Blue 400 - 550 Red 550 - 700 NIR 780 - 960 Methane 875 - 915 Panchromatic 400 - 960 --------------- ------------------------------ MVIC ---- MVIC shall have a field of view (FOV) in the cross-track direction of 5.7deg. MVIC shall have a FOV that is determined by the TDI data acquisition range in the in-track direction. MVIC will have a FOV of 5.7deg x 0.15deg for images obtained using frame transfer. MVIC will use a front-side illuminated CCD silicon detector array. MVIC will possess one TDI sensor for each of the blue, red, NIR, and methane bands. MVIC will possess one frame transfer sensor. MVIC will possess two TDI sensors for the panchromatic band, to be referred to as Pan1 and Pan2. The detector shall be sensitive to light at wavelengths from 400 to 960 nm. The CCD detector shall have pixels of size 13 X 13 microns +/- 0.1 microns. Each TDI sensor shall have 32 x 5000 photosensitive pixels. The frame transfer sensor shall possess 128 x 5000 photosensitive pixels. LEISA ----- The LEISA detector shall be a 256x256 HgCdTe array with 40 micron square pixels. The detector shall be sensitive to light from 1.25-2.50 microns. Definitions/Glossary of Terms ----------------------------- Cross-Track Direction - In spacecraft coordinates, motion that includes a component in the +Z or -Z directions where the Z-axis is the axis of rotation for the spacecraft in scan mode. In-Track Direction - In spacecraft coordinates, motion in the X-Y plane associated with spacecraft rotation about the Z-axis. Instantaneous Field of View - The field of view imaged by the full detector array with the spacecraft in staring mode. OpNav Imaging Mode - For the MVIC sensor, this mode is used to take data to meet OpNav requirements. 2D imaging for OpNav imaging mode is acquired through frame transfer with the spacecraft in staring mode. Scan Mode - In spacecraft coordinates, spacecraft rotation about the Z-axis. Scan mode is used to acquire data for 2D images through synchronized physical scanning and detector array readout. In scan mode, the field of view in the in-track direction is determined by the length of observation, IFOV, and the scan rate. Science Imaging Mode - For the MVIC sensor, this mode is used to take data to meet science requirements. 2D imaging for science imaging mode is acquired through synchronized operation with 1D spacecraft maneuvers. The detector readout occurs in TDI mode. Single Pixel Instantaneous Field of View - The field of view for a single pixel in a detector array. Staring Mode - The spacecraft is pointed at a specific point and does not have rotation about the Z-axis of the spacecraft. Staring mode is used to acquire data for 2D images through frame transfer techniques for 2D detector arrays. TDI Mode Data Acquisition - For TDI data acquisition, a 2D image is obtained by scanning around the Z axis. Looking down on the spacecraft from above the ecliptic, in the nominal flight configuration (+Z pointing up, -X pointing at Pluto or Charon), the spacecraft scans from left to right clockwise. TDI FOV - This indicates that the field of view for an image is variable because it is related to spacecraft motion. Roughly, TDI FOV is the total angle scanned by the spacecraft for a single observation. The TDI FOV is comprised of multiples of the single pixel instantaneous field of view. For a single observation by the FOV in the cross track direction. LEISA Data Acquisition - For LEISA data acquisition, a 2D spectral image is obtained by scanning around the Z axis in either the clockwise or counterclockwise direction.'' RALPH Field of View Parameters ---------------------------------------------------------- The detectors that constitute Ralph are MVIC, LEISA, and SIA. MVIC has several focal plane arrays. -- Multispectral Visible Imaging Camera (MVIC) -- MVIC Frame Transfer Array (FT) -- MVIC Pan 1 Array (PAN1) -- MVIC Pan 2 Array (PAN2) -- MVIC Red Array (RED) -- MVIC Blue Transfer Array (BLUE) -- MVIC Methane Array (METHANE) -- MVIC NIR Array (NIR) -- Linear Etalon Imaging Spectral Array (LEISA) -- Solar Illumination Aperture (SIA) The field of view sizes for the above detectors/arrays are given in [11], with the exception of the PAN1, PAN2, RED, BLUE, METHANE, and NIR vertical (along-scan) directions. Each of those arrays has 32 pixels per row [11]. The fields of view for those arrays were calculated using the following formula: along-scan FOV size = ( rows * IFOV ) deg = ( 32 * 19.8/1000000 rad ) * ( 180/pi ) deg = 0.036 deg The cross-scan FOV size is 5.67 deg for each of the MVIC arrays [11]. The field of view sizes are given in the tables below. Rectangular FOVs (coordinates in parenthesis are in the spacecraft frame): ---------- ---------------- ---------------- ---------------- Detector Horizontal Vertical Cone Axis (cross scan) ---------- ---------------- ---------------- ---------------- FT 5.67 deg (in Z) 0.145 deg (in Y) boresight (-X) PAN1 5.67 deg (in Z) 0.036 deg (in Y) boresight (-X) PAN2 5.67 deg (in Z) 0.036 deg (in Y) boresight (-X) RED 5.67 deg (in Z) 0.036 deg (in Y) boresight (-X) BLUE 5.67 deg (in Z) 0.036 deg (in Y) boresight (-X) METHANE 5.67 deg (in Z) 0.036 deg (in Y) boresight (-X) NIR 5.67 deg (in Z) 0.036 deg (in Y) boresight (-X) LEISA 0.89 deg 0.89 deg boresight (-X) ---------- ---------------- ---------------- ---------------- Circular FOV: ---------- ---------------- ---------------- Detector Diameter Cone Axis ---------- ---------------- ---------------- SIA 5.0 degrees near +Y ---------- ---------------- ---------------- The SIA cone axis is nominally aligned with the ALICE Solar Occultation Channel (SOC) [3], whose boresight is aligned to a line in the spacecraft YZ plane right-hand rotated by 2 degrees around the X axis from the REX boresight (spacecraft Y axis) [8]. The ALICE SOC FOV is illustrated in [8]. The MVIC and LEISA boresights are nominally aligned to the spacecraft -X axis. The INS[ID]_FOV_FRAME, INS[ID]_FOV_SHAPE, INS[ID]_BORESIGHT, and FOV ANGLES specification keywords defined below are used to describe the instrument field of view. Since the SIA detector has a circular field of view, and the MVIC arrays and LEISA have rectangular ones, the INS[ID]_FOV_SHAPE will either be 'CIRCLE' or 'RECTANGLE'. For SIA, GETFOV returns a single vector that lies along the edge of the circular cone, and for the MVIC arrays and LEISA, GETFOV returns four boundary corner vectors. Note that a field of view is not defined for the instrument boresight. The SPICE routine GDPOOL may be used to get the NH_RALPH boresight. Multispectral Visible Imaging Camera (MVIC) FOV Definitions There is no single field of view definition for the Ralph instrument [13], but the instrument boresight is by definition the center of the frame transfer array. That boresight is the -X axis of the NH_RALPH frame: \begindata INS-98200_FOV_FRAME = 'NH_RALPH' INS-98200_BORESIGHT = ( -1.0, 0.0, 0.0 ) \begintext Each of the MVIC arrays, LEISA, and SIA have a field of view defined. Those definitions are below. Since the MVIC frame transfer array's angular separation in Y is 0.145 degrees, looking down the Z axis in the instrument frame we have: (Note we are arbitrarily choosing vectors that terminate in the X=-1 plane.) ^ Y | inst | |. | | `. | | `. | | o`. | .0725 `. | <---------------o -X | ,' Z (out) inst | ,' inst | ,' | ,' |' |--- 1.0 ---| Plane Z = 0 And since the MVIC frame transfer array's angular separation in Z is 5.67 degrees, looking up the Y axis in the instrument frame, we have: (Note we are arbitrarily choosing vectors that terminate in the X=-1 plane.) ^ Z | inst | |. | | `. | | `. | | o`. | 2.835 `. | <---------------x -X | ,' Y (in) inst | ,' inst | ,' | ,' |' |--- 1.0 ---| Plane Y = 0 These FOV values for the MVIC frame transfer array are given in the keywords below: \begindata INS-98203_FOV_FRAME = 'NH_RALPH_MVIC_FT' INS-98203_FOV_SHAPE = 'RECTANGLE' INS-98203_BORESIGHT = ( -1.0, 0.0, 0.0 ) INS-98203_FOV_CLASS_SPEC = 'ANGLES' INS-98203_FOV_REF_VECTOR = ( 0.0, +1.0, 0.0 ) INS-98203_FOV_REF_ANGLE = ( 0.0725 ) INS-98203_FOV_CROSS_ANGLE = ( 2.835 ) INS-98203_FOV_ANGLE_UNITS = 'DEGREES' \begintext The angular separation in Y for each of the TDI arrays is 0.036 degrees. Looking down the Z axis in the TDI frame we have: (Note we are arbitrarily choosing vectors that terminate in the X=-1 plane.) ^ Y | inst | |. | | `. | | `. | | o`. | 0.018 `. | <---------------o -X | ,' Z (out) inst | ,' inst | ,' | ,' |' |--- 1.0 ---| Plane Z = 0 Which leads to the following field of view definitions: \begindata INS-98204_FOV_FRAME = 'NH_RALPH_MVIC_PAN2' INS-98204_FOV_SHAPE = 'RECTANGLE' INS-98204_BORESIGHT = ( -1.0, 0.0, 0.0 ) INS-98204_FOV_CLASS_SPEC = 'ANGLES' INS-98204_FOV_REF_VECTOR = ( 0.0, +1.0, 0.0 ) INS-98204_FOV_REF_ANGLE = ( 0.018 ) INS-98204_FOV_CROSS_ANGLE = ( 2.835 ) INS-98204_FOV_ANGLE_UNITS = 'DEGREES' INS-98205_FOV_FRAME = 'NH_RALPH_MVIC_PAN1' INS-98205_FOV_SHAPE = 'RECTANGLE' INS-98205_BORESIGHT = ( -1.0, 0.0, 0.0 ) INS-98205_FOV_CLASS_SPEC = 'ANGLES' INS-98205_FOV_REF_VECTOR = ( 0.0, +1.0, 0.0 ) INS-98205_FOV_REF_ANGLE = ( 0.018 ) INS-98205_FOV_CROSS_ANGLE = ( 2.835 ) INS-98205_FOV_ANGLE_UNITS = 'DEGREES' INS-98206_FOV_FRAME = 'NH_RALPH_MVIC_RED' INS-98206_FOV_SHAPE = 'RECTANGLE' INS-98206_BORESIGHT = ( -1.0, 0.0, 0.0 ) INS-98206_FOV_CLASS_SPEC = 'ANGLES' INS-98206_FOV_REF_VECTOR = ( 0.0, +1.0, 0.0 ) INS-98206_FOV_REF_ANGLE = ( 0.018 ) INS-98206_FOV_CROSS_ANGLE = ( 2.835 ) INS-98206_FOV_ANGLE_UNITS = 'DEGREES' INS-98207_FOV_FRAME = 'NH_RALPH_MVIC_BLUE' INS-98207_FOV_SHAPE = 'RECTANGLE' INS-98207_BORESIGHT = ( -1.0, 0.0, 0.0 ) INS-98207_FOV_CLASS_SPEC = 'ANGLES' INS-98207_FOV_REF_VECTOR = ( 0.0, +1.0, 0.0 ) INS-98207_FOV_REF_ANGLE = ( 0.018 ) INS-98207_FOV_CROSS_ANGLE = ( 2.835 ) INS-98207_FOV_ANGLE_UNITS = 'DEGREES' INS-98208_FOV_FRAME = 'NH_RALPH_MVIC_METHANE' INS-98208_FOV_SHAPE = 'RECTANGLE' INS-98208_BORESIGHT = ( -1.0, 0.0, 0.0 ) INS-98208_FOV_CLASS_SPEC = 'ANGLES' INS-98208_FOV_REF_VECTOR = ( 0.0, +1.0, 0.0 ) INS-98208_FOV_REF_ANGLE = ( 0.018 ) INS-98208_FOV_CROSS_ANGLE = ( 2.835 ) INS-98208_FOV_ANGLE_UNITS = 'DEGREES' INS-98209_FOV_FRAME = 'NH_RALPH_MVIC_NIR' INS-98209_FOV_SHAPE = 'RECTANGLE' INS-98209_BORESIGHT = ( -1.0, 0.0, 0.0 ) INS-98209_FOV_CLASS_SPEC = 'ANGLES' INS-98209_FOV_REF_VECTOR = ( 0.0, +1.0, 0.0 ) INS-98209_FOV_REF_ANGLE = ( 0.018 ) INS-98209_FOV_CROSS_ANGLE = ( 2.835 ) INS-98209_FOV_ANGLE_UNITS = 'DEGREES' \begintext From [11], the MVIC pixels are 13 microns wide with a single pixel FOV of 19.8 microradians. These values are captured for each of the MVIC arrays in the keywords below. \begindata INS-98203_PIXEL_SIZE = ( 13.0 ) INS-98203_IFOV = ( 19.8 ) INS-98204_PIXEL_SIZE = ( 13.0 ) INS-98204_IFOV = ( 19.8 ) INS-98205_PIXEL_SIZE = ( 13.0 ) INS-98205_IFOV = ( 19.8 ) INS-98206_PIXEL_SIZE = ( 13.0 ) INS-98206_IFOV = ( 19.8 ) INS-98207_PIXEL_SIZE = ( 13.0 ) INS-98207_IFOV = ( 19.8 ) INS-98208_PIXEL_SIZE = ( 13.0 ) INS-98208_IFOV = ( 19.8 ) INS-98209_PIXEL_SIZE = ( 13.0 ) INS-98209_IFOV = ( 19.8 ) \begintext Linear Etalon Imaging Spectral Array (LEISA) FOV Definition Since LEISA's angular separation in Y is 0.89 degrees, looking down the Z axis in the spacecraft frame we have: (Note we are arbitrarily choosing vectors that terminate in the X=-1 plane.) ^ Y | sc | |. | | `. | | `. | | o`. | |.445 `. | <---------------o -X | ,' Z (out) sc | ,' sc | ,' | ,' |' |--- 1.0 ---| Plane Z = 0 Since LEISA's field of view is square, a similar computation yields the Z component. These FOV values for MVIC are given in the keywords below: \begindata INS-98201_FOV_FRAME = 'NH_RALPH_LEISA' INS-98201_FOV_SHAPE = 'RECTANGLE' INS-98201_BORESIGHT = ( -1.0, 0.0, 0.0 ) INS-98201_FOV_CLASS_SPEC = 'ANGLES' INS-98201_FOV_REF_VECTOR = ( 0.0, 1.0, 0.0 ) INS-98201_FOV_REF_ANGLE = ( 0.445 ) INS-98201_FOV_CROSS_ANGLE = ( 0.445 ) INS-98201_FOV_ANGLE_UNITS = 'DEGREES' \begintext From [11], the LEISA pixels are 40 microns wide with a single pixel FOV of 61 microradians. These values are captured in the keywords below. INS-98201_PIXEL_SIZE = ( 40.0 ) INS-98201_IFOV = ( 61.0 ) The above IFOV is nominal and has been adjusted in-flight to the value below [12]. The pixel size in microns is the nominal value: \begindata INS-98201_PIXEL_SIZE = ( 40.0 ) INS-98201_IFOV = ( 62.065 ) \begintext Solar Illumination Aperture (SIA) FOV Definition The SIA frame is defined such that the boresight is the instrument Z axis. The field of view is circular with a 5 degree angular separation. A cross section is illustrated below. (Note we are arbitrarily choosing vectors that terminate in the Z=1 plane.) Y ^ sc | | | | | _.-| | _.-' o| |_.-' 2.5 | x--------------> X (in)`~._ | Z sc `~._ | ins `~.| |--- 1.0 ---| Plane X = 0 Because the SIA field of view is circular, the FOV reference vector (keyword FOV_REF_VECTOR) is any vector with a component that lies in a plane normal to the field of view boresight. We chose the +Y axis of the instrument frame. These FOV values are given in the keywords below: \begindata INS-98202_FOV_FRAME = 'NH_RALPH_SIA' INS-98202_FOV_SHAPE = 'CIRCLE' INS-98202_BORESIGHT = ( 0.0, 0.0, 1.0 ) INS-98202_FOV_CLASS_SPEC = 'ANGLES' INS-98202_FOV_REF_VECTOR = ( 0.0, 1.0, 0.0 ) INS-98202_FOV_REF_ANGLE = ( 2.5 ) INS-98202_FOV_ANGLE_UNITS = 'DEGREES' \begintext