KPL/IK LORRI Instrument Kernel ============================================================================== This instrument kernel (I-kernel) contains references to the mounting alignment, internal and FOV geometry for the New Horizons LOng Range Reconnaissance Imager (LORRI). 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 LORRI I-kernel might have an entry as follows: TEXT_KERNEL_ID += 'NEWHORIZONS_LORRI V0.0.3 04-JANUARY-2007 IK' | | | | | | | | KERNEL NAME <-------+ | | | | | V VERSION <-------+ | KERNEL TYPE | V ENTRY DATE LORRI I-Kernel Version: \begindata TEXT_KERNEL_ID += 'NEWHORIZONS_LORRI V0.0.3 04-JANUARY-2007 IK' NAIF_BODY_NAME += ( 'NH_LORRI' ) NAIF_BODY_CODE += ( -98300 ) NAIF_BODY_NAME += ( 'NH_LORRI_1X1' ) NAIF_BODY_CODE += ( -98301 ) NAIF_BODY_NAME += ( 'NH_LORRI_4X4' ) NAIF_BODY_CODE += ( -98302 ) \begintext Version 0.0.3 -- January 4, 2007 -- Lillian Nguyen, JHU/APL -- Added field of view information for the 1x1 and 4x4 binning modes. -- Added optical and CCD geometry parameters, and reference vector. Version 0.0.2 -- October 4, 2006 -- Lillian Nguyen, JHU/APL -- Removed the 3-letter frame NH_LOR. Version 0.0.1 -- January 25, 2006 -- Lillian Nguyen -- Frame definition and frame diagram modified after review by instrument team. Version 0.0.0 -- January 5, 2006 -- Lillian Nguyen -- Draft Version. NOT YET APPROVED BY INSTRUMENT TEAM. References ---------------------------------------------------------- 1. LOng-Range Reconnaissance Imager (LORRI) Specification Document, 7400-9000 Rev A. 2. ``Kernel Pool Required Reading'' 3. Spacecraft to LORRI Interface Control Document (ICD), 7399-9048, Rev B. 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. LOng-Range Reconnaissance Imager (LORRI) User's Manual, 7400-9601, dated Jan. 10, 2006. 8. LORRI_orientation_1-9-06, received on 1/23/2006 by e-mail from Hal Weaver along with a description of the LORRI frame relative to the spacecraft frame. Also a phone conversation with Hal clarifying the diagrams in the document. 9. Discussions with Howard Taylor regarding LORRI instrument frame definition and LORRI keywords, 12/21/2006. 10. Response to LORRI OpNav action items, forwarded in an e-mail from Howard Taylor on 12/21/2006. 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 LORRI instrument. The remainder of the name is an underscore character followed by the unique name of the data item. For example, the LORRI boresight direction in the LORRI frame (``NH_LORRI'' -- see [5] ) is specified by: INS-98300_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. LORRI description ---------------------------------------------------------- From [4]: ``The instrument that provides the highest spatial resolution on New Horizons is LORRI - short for Long Range Reconnaissance Imager - which consists of a telescope with a 8.2-inch (20.8-centimeter) aperture that focuses visible light onto a charge coupled device (CCD). LORRI has a very simple design; there are no filters or moving parts. Near the time of closest approach, LORRI will take images of Pluto's surface at football-field sized resolution, resolving features approximately 100 yards or 100 meters across.'' From [1]: ``The Long Range Reconnaissance Imager, LORRI, is a modest aperture (200 mm), narrow-angle camera capable of producing high-resolution imagery. The LORRI will provide imagery of Pluto-Charon, beginning 90 days prior to encounter. From 75 days regarding before closest approach, LORRI will provide resolution of Pluto beyond that achievable using HST. . . . LORRI imager consists of a 208 mm aperture Ritchie-Chrétien telescope made of silicon carbide. The telescope is f/12.75, and feeds an unfiltered, 1024 x 1024 frame transfer CCD. The effective band-pass is primarily limited by the CCD response to 350 to 850 nm. There is a long composite baffle running the length of the instrument, and smaller baffles at the outside of the secondary and inside of the primary. The assembly is mounted to the spacecraft via 3 titanium legs. . . . LORRI operations consist of imaging at Jupiter, Pluto/Charon, and one to three Kuiper Belt Objects. Additionally, various calibration images and functional tests will be performed.'' From [3]: ``The LOng Range Reconnaissance Imager (LORRI) is intended to complement the PERSI/MVIC wide angle, medium resolution imagers. LORRI is controlled independently of PERSI/MVIC. It will provide higher resolution imagery with a much narrower field-of-view and contributes a measure of redundancy to the mission. Its boresight is aligned to within 0.1 deg of PERSI/MVIC to support coordinated operations when operated in their "framing mode". The long-range capability of LORRI will permit the receipt of high-resolution observations of Pluto-Charon at least 75 days before their encounter and of the Kuiper-Belt Objects (KBOs). . . . LORRI is a panchromatic visible imager with an angular resolution of 5 rad/pixel and a field-of-view (FOV) of 0.29 deg x 0.29 deg. It consists of a 20-cm aperture, f/13 telescope imaging onto a CCD focal plane. The combined mass of the telescope structure, mirrors, supporting electronics, and aperture door is 8.593 Kg. To reduce unwanted stray light, the telescope is heavily baffled. LORRI is fixed mounted inside the spacecraft structure within a baffle tube protruding through the spacecraft structure. An aperture door provides contamination protection during ground operation, launch, and early cruise.'' LORRI Frame ---------------------------------------------------------- The following diagrams are reproduced from [8]. When viewed by an observer looking out LORRI's boresight, the spacecraft axes on the sky will look like: Diagram 1 --------- Sky View Looking out from LORRI _________________________________ | | | | | ^ +Y | | | sc | | | | | | | | | | | <--------o | | +Z +X (out) | | sc sc | | | | | | | | | |_________________________________| The LORRI optics inverts images in both the Y and Z directions, so that the projection of these spacecraft axes onto the LORRI CCD will look like the following: (Note that we are looking INTO the LORRI telescope in the diagram below, whereas above we were looking outwards, hence the position of the +Z axis does not appear to have changed when in fact it has flipped). Diagram 2 --------- Looking in at the LORRI CCD _________________________________ | | Spacecraft Axes | | | | ^ +Y | | | sc increasing ^ | | | columns | | | x-----> +Z | | +Z +X (in) | +X (in) sc | | <---------x | sc | | | | | | | | | | | | | | | | | | V +Y | | | | O_________________________________| ------------------------> [0,0]=[column, row] increasing rows Note that in Diagram 2, the axes are not labelled Z and Y to clarify sc sc that although these are still spacecraft coordinates, they are the projections of the spacecraft axes from Diagram 1 onto the LORRI CCD, not the actual spacecraft axes. The actual spacecraft axes are depicted to the right of Diagram 2. The origin in the CCD view is at the bottom left, and the CCD storage area and serial register are to the left. The LORRI IDL display further inverts the image in Diagram 2 about the diagonal originating at [0,0]: Diagram 3 --------- LORRI IDL Display _________________________________ | | Spacecraft Axes | | | | ^ +Z | | | sc increasing ^ | | | rows | | | o-----> +Y | | +Y +X (out) | +X (out) sc | | <---------x | sc | | | | | | | | | | | | | | | | | | V +Z | | | | O_________________________________| ------------------------> [0,0]=[column, row] increasing columns Taken from [8], we have the following coordinate system definition for the LORRI frame: The -X axis in instrument coordinates is defined to be the boresight. The +Y axis is approximately aligned to the spacecraft +Y axis and is in the direction of increasing columns. To form a right-handed frame, the +Z axis in instrument coordinates is in the direction of increasing rows and is approximately aligned to spacecraft +Z axis. The coordinate system definition for the LORRI frame has been changed [9] from the above to the following: The -Z axis in instrument coordinates is defined to be the boresight and is approximately aligned with the spacecraft -X axis. The Y axis in instrument coordinates is approximately aligned with the spacecraft -Z axis and is in the direction of increasing rows. The X axis in instrument coordinates is approximately aligned with the spacecraft -Y axis and is in the direction of increasing columns. LORRI Field of View Parameters ---------------------------------------------------------- From [10], the LORRI FOV is 0.2907 deg square. Since LORRI's angular separation in Y is 0.2907 deg, looking up the +Y axis in the instrument frame we have: (Note we are arbitrarily choosing vectors that terminate in the Z=-1 plane.) X ^ inst| | | | _.-| | _.-' | o |_.-' 0.14535 x--------------> Y (in) `~._ | -Z inst `~._ | inst `~.| |--- 1.0 ---| Plane X = 0 Since LORRI's field of view is square, a similar computation yields the Y component. These FOV values for LORRI are given in the keywords below: \begindata INS-98300_FOV_FRAME = 'NH_LORRI' INS-98300_FOV_SHAPE = 'RECTANGLE' INS-98300_BORESIGHT = ( 0.0, 0.0, -1.0 ) INS-98300_FOV_CLASS_SPEC = 'ANGLES' INS-98300_FOV_REF_VECTOR = ( 1.0, 0.0, 0.0 ) INS-98300_FOV_REF_ANGLE = ( 0.14535 ) INS-98300_FOV_CROSS_ANGLE = ( 0.14535 ) INS-98300_FOV_ANGLE_UNITS = 'DEGREES' \begintext And are duplicated for the 1x1 and 4x4 binning mode frames: \begindata INS-98301_FOV_FRAME = 'NH_LORRI_1X1' INS-98301_FOV_SHAPE = 'RECTANGLE' INS-98301_BORESIGHT = ( 0.0, 0.0, -1.0 ) INS-98301_FOV_CLASS_SPEC = 'ANGLES' INS-98301_FOV_REF_VECTOR = ( 1.0, 0.0, 0.0 ) INS-98301_FOV_REF_ANGLE = ( 0.14535 ) INS-98301_FOV_CROSS_ANGLE = ( 0.14535 ) INS-98301_FOV_ANGLE_UNITS = 'DEGREES' INS-98302_FOV_FRAME = 'NH_LORRI_4X4' INS-98302_FOV_SHAPE = 'RECTANGLE' INS-98302_BORESIGHT = ( 0.0, 0.0, -1.0 ) INS-98302_FOV_CLASS_SPEC = 'ANGLES' INS-98302_FOV_REF_VECTOR = ( 1.0, 0.0, 0.0 ) INS-98302_FOV_REF_ANGLE = ( 0.14535 ) INS-98302_FOV_CROSS_ANGLE = ( 0.14535 ) INS-98302_FOV_ANGLE_UNITS = 'DEGREES' \begintext LORRI Optics Parameters ---------------------------------------------------------- From [10], LORRI has the following optics parameters: ----------------------------------------------------------------- parameter 1x1 binning mode 4x4 binning mode ----------------------------------------------------------------- Focal length (meters) 2.624 2.624 f-number 12.62 12.62 IFOV (microrad/pixel) 4.955 19.82 Aperture diameter (cm) 20.8 20.8 ----------------------------------------------------------------- These parameters are captured in the following keywords in the same units as in the table: \begindata INS-98301_FOCAL_LENGTH = ( 2.624 ) INS-98301_F/NUMBER = ( 12.62 ) INS-98301_IFOV = ( 4.955 ) INS-98301_APERTURE_DIAMETER = ( 20.8 ) INS-98302_FOCAL_LENGTH = ( 2.624 ) INS-98302_F/NUMBER = ( 12.62 ) INS-98302_IFOV = ( 19.82 ) INS-98302_APERTURE_DIAMETER = ( 20.8 ) \begintext LORRI CCD Detector Parameters ---------------------------------------------------------- From [9] and [10], LORRI has the following CCD parameters: ----------------------------------------------------------------- parameter 1x1 binning mode 4x4 binning mode ----------------------------------------------------------------- Detector array size 1024 x 1024 256 x 256 Pixel size (microns) 13 x 13 52 x 52 CCD center ( 511.5, 511.5) ( 127.5, 127.5 ) ----------------------------------------------------------------- These parameters are captured in the following keywords in the same units as in the table: \begindata INS-98301_PIXEL_SAMPLES = ( 1024 ) INS-98301_PIXEL_LINES = ( 1024 ) INS-98301_PIXEL_SIZE = ( 13 ) INS-98301_CCD_CENTER = ( 511.5, 511.5 ) INS-98302_PIXEL_SAMPLES = ( 256 ) INS-98302_PIXEL_LINES = ( 256 ) INS-98302_PIXEL_SIZE = ( 52 ) INS-98302_CCD_CENTER = ( 127.5, 127.5 ) \begintext Also defined here is the celestial position angle reference vector. This vector defines the position angle, or angle from celestial north (and passing through celestial east) to the reference vector. \begindata INS-98300_REFERENCE_VECTOR = ( 1.0, 0.0, 0.0 ) INS-98301_REFERENCE_VECTOR = ( 1.0, 0.0, 0.0 ) INS-98302_REFERENCE_VECTOR = ( 1.0, 0.0, 0.0 ) \begintext Platform ID -------------------------------------------------------- This number is the NAIF instrument ID of the platform on which the instrument is mounted. INS-98300_PLATFORM_ID = ( -98000 ) INS-98301_PLATFORM_ID = ( -98000 ) INS-98302_PLATFORM_ID = ( -98000 )