KPL/IK JANUS Instrument Kernel =============================================================================== This instrument kernel (I-kernel) contains the JUICE Jovis, Amorum ac Natorum Undique Scrutator (JANUS) camera system optics, detector and field-of-view (FOV) parameters. Version and Date ------------------------------------------------------------------------------ Version 0.8 -- April 17, 2022 -- Luca Penasa, INAF Livio Agostini, INAF Cecilia Tubiana, INAF Klaus Dieter Metz, DLR Marc Costa Sitja, ESAC/ESA Updated detector parameters and added filter wheels keywords. Reordered filter list to be in the same order of the wheel. Version 0.7 -- June 30, 2022 -- Marc Costa Sitja, ESAC/ESA Corrected INS-28200_CCD_CENTER definition and fixed descriptions. Version 0.6 -- January 08, 2021 -- Alfredo Escalante Lopez, ESAC/ESA, Pasquale Palumbo, Parthenope, Cecilia Tubiana, IAPS/INAF Updated Instrument Description, Optical Parameters, and Detector Parameters sections. Corrected typos. Corrected INS-28200_PIXEL_SAMPLES and INS-28200_PIXEL_LINES in Detector Parameters section. Added some optical parameters. Version 0.5 -- August 01, 2016 -- Marc Costa Sitja, ESAC/ESA, Thomas Roatsch, DLR Added Camera sensor definitions as indicated by Thomas Roatsch and corrected the required values. Version 0.4 -- July 11, 2016 -- Marc Costa Sitja, ESAC/ESA Corrected instrument description. Corrected FOV value now provided in degrees instead of radians. Initial Release. Pending review by the JANUS instrument team. Version 0.3 -- June 04, 2016 -- Marc Costa Sitja, ESAC/ESA Updated all NAIF ID codes from -907* to -28* since the JUICE spacecraft NAIF ID has been updated from -907 to -28. Version 0.2 -- May 11, 2016 -- Jorge Diaz del Rio, ODC Space Added naming conventions and conventions for specifying data section. Corrected typos in text. Version 0.1 -- March 04, 2016 -- Jorge Diaz del Rio, ODC Space Preliminary version. Pending review by the JANUS instrument and JUICE Science Operations Working Group team. Version 0.0 -- July 24, 2013 -- Marc Costa Sitja, ISDEFE/ESA Initial Release. References ------------------------------------------------------------------------------ 1. ``Kernel Pool Required Reading'' 2. ``C-kernel Required Reading'' 3. JUICE Frames Definition Kernel (FK), latest version. 4. ``JUICE - Jupiter Icy Moons Explorer. Exploring the emergence of habitable worlds around gas giants. Definition Study report,'' ESA/SRE(2014)1, September 2014 (JUICE Red book v1.0) 5. ``JANUS - Camera for the ESA JUICE mission Experiment Interface Document - Part B,'' JUI-JAC-JAN-EID-B-001, Issue E, 30 January 2020 (formally delivered in July 2020) 6. ``JANUS User Manual'' JUI-FNM-JAN-MAN-001, Revision F, 04/03/22 Contact Information ------------------------------------------------------------------------------ If you have any questions regarding this file contact SPICE support at ESAC: Alfredo Escalante Lopez (+34) 91-8131-429 spice@sciops.esa.int or the JUICE Science Operations Center at ESAC: Marc Costa Sitja (+34) 646-746-711 Marc.Costa@ext.esa.int Implementation Notes ------------------------------------------------------------------------------ Applications that need SPICE I-kernel data must ``load'' the I-kernel file, normally during program initialization. The SPICE routine FURNSH loads a kernel file into the pool as shown below. CALL FURNSH ( 'frame_kernel_name' ) -- FORTRAN furnsh_c ( "frame_kernel_name" ); -- C cspice_furnsh, frame_kernel_name -- IDL cspice_furnsh( 'frame_kernel_name' ) -- MATLAB Loading the kernel using the SPICELIB routine FURNSH causes the data items and their associated values present in the kernel to become associated with a data structure called the ``kernel pool''. Once the file has been loaded, the SPICE routine GETFOV (getfov_c in C, cspice_getfov in IDL and MATLAB) can be used to retrieve FOV parameters for a given instrument or structure. The application program may obtain the value(s) for any other IK data item using the SPICELIB routines GDPOOL, GIPOOL, GCPOOL (gdpool_c, gipool_c, gcpool_c in C, cspice_gdpool, cspice_gipool, cspice_gcpool in IDL and MATLAB). See [1] for details. This file was created with, and can be updated with a text editor or word processor. Naming Conventions and Conventions for Specifying Data ------------------------------------------------------------------------------ All names referencing values in this IK file start with the characters `INS' followed by the NAIF JUICE spacecraft ID number (-28) followed by a NAIF three digit ID code for one of the JANUS sensors. This is the full list of names and IDs for the JANUS sensors described by this IK file: Name NAIF ID --------------------- --------- JUICE_JANUS -28200 The remainder of the keyword name is an underscore character followed by the unique name of the data item. For example, the JANUS Camera boresight direction in the JUICE_JANUS frame is specified by: INS-28200_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. Instrument Description and Overview ------------------------------------------------------------------------------ Instrument Description: ----------------------- JANUS (Jovis Amorum ac Natorum Undique Scrutator) is the high resolution camera onboard the JUICE spacecraft. JANUS is made of three units: the Optical Head Unit (OHU), which is essentially a catadioptric telescope with a cover, a baffle, a filter wheel with 13 visible wavelength filters and a 3 Mpixel detector; the Proximity Electronics Unit (PEU), which controls the detector and digitalize its signal; the Main Electronics Unit (MEU), which distributes power to the instrument, controls the mechanisms and includes a computer and its software that controls all instrument functionalities, receives telecommands and delivers telemetry and data to ground through the satellite interface. The main characteristics of the optical head unit are provided in the following table: Specification Value -------------------------------- -------------------------------- Aperture 116 mm Effective Focal Length 467 mm F/# w/o obstruction 4.02 F/# w/ obstruction (radiometric) 4.5 Field of View 1.72 x 1.29 degrees Detector size 2000 x 1504 pixels Pixel size 7 micrometer Plate scale 15 microrad/pixel = 3.09"/pixel Spectral range 340 - 1080 nm JANUS is equiped with a Teledyne-e2v CMOS rectuangular detector with 2000 x 1504 pixels and pixel size of 7 x 7 square micrometer. The short side of the detector (+Y JUICE_JANUS) is parallel to +Y JUICE_SPACECRAFT (flight direction), while the long side (+X JUICE_JANUS) is parallel to +X JUICE_SPACECRAFT (across track) in order to maximize the imaging coverage while in Ganymede in orbit and during satellites closest approach. Mounting Alignment ------------------------------------------------------------------------------ Refer to the latest version of the JUICE Frames Definition Kernel (FK) [3] for the JANUS reference frame definitions and mounting alignment information. JANUS Apparent Field-of-View Layout ------------------------------------------------------------------------------ This diagram illustrates the JANUS apparent FOV layout when operating in normal mode (no-binning). This FOV is associated with detector instrument IDs -28200. The diagram also shows the apparent position of the four 376 px wide tiles the sensor is built with (T1 to T4). -- ROWS/LINES NUMBER --> +Zjanus is into the ROW/LINE page | (1,1) v | *-------------------------------------. ------ --- C|S | T1 | | ^ | 376 O|A | | | | px L|M |-----------------------------|-------| | --- U|P | T2 | | M|L | +Zjanus | +Xjanus | 1504 pixels N|E |------------------X---------------------> | 1.29 degrees S|S | T3 | | | | v | | | | |------------------|----------|-------| | COLUMN/ | T4 | | | SAMPLE->|- - - - - - - - - | - - - - -|- - - -| v '------------------|------------------' ------ v +Yjanus | Nom. Direction | NOM. CROSS TRACK | | of Flight |<----------------------------------->| v | 2000 pixels | 1.72 degrees The coordinate system with values (1,1) in the center of the pixel located at the top-left of the FOV above is used to provide the coordinates of the CCD_CENTER keyword in the ``Detector Parameters'' section below, as (columns, rows). Optical Parameters ------------------------------------------------------------------------------ JANUS is equipped with a set of 13 optical filters (1 panchromatic, 4 broadband, and 8 narrowband) covering the wavelength range from 340 to 1080 nm. The filters are mounted on the Filter Wheel Mechanism (FWM), which positions the selected filters in front of the image detector with the necessary accuracy. The list of filters, in the same order as they are mounted on the filter wheel, is provided in the following table, which includes also the progressive NAIF IDs. NAIF Center [nm] Id ID Name /FWHM [nm] Description ---- ------ ------------ ------------ ----------------------------- 1 -28211 Panchromatic 650/500 Monochromatic imaging 2 -28212 Blue 450/60 Satellite colours 3 -28213 Green 540/60 Satellite colours, background for Na 4 -28214 Red 646/60 Satellite colours, background for Halpha 5 -28215 CMT medium 750/20 Continuum for strong Jovian methane band, geology 6 -28216 Na 590/10 Sodium D-lines in exospheres 7 -28217 MT strong 889/20 Strong Jovian methane band 8 -28218 CMT strong 940/20 Continuum for medium Jovian methane band, Fe2+ on satellites 9 -28219 MT medium 727/10 Medium Jovian methane band 10 -28220 Violet 380/80 UV slope 11 -28221 NIR 1 910/80 Fe2+, Io lava spots 12 -28222 NIR 2 1015/130 Fe2+, Io lava spots - GALA laser altimeter footprint 13 -28223 Halpha 656/10 Halpha-line for aurorae and lightning \begindata INS-28211_BANDCENTER = ( 650.0 ) INS-28211_BANDWIDTH = ( 500.0 ) INS-28212_BANDCENTER = ( 450.0 ) INS-28212_BANDWIDTH = ( 60.0 ) INS-28213_BANDCENTER = ( 540.0 ) INS-28213_BANDWIDTH = ( 60.0 ) INS-28214_BANDCENTER = ( 646.0 ) INS-28214_BANDWIDTH = ( 60.0 ) INS-28215_BANDCENTER = ( 750.0 ) INS-28215_BANDWIDTH = ( 20.0 ) INS-28216_BANDCENTER = ( 590.0 ) INS-28216_BANDWIDTH = ( 10.0 ) INS-28217_BANDCENTER = ( 889.0 ) INS-28217_BANDWIDTH = ( 20.0 ) INS-28218_BANDCENTER = ( 940.0 ) INS-28218_BANDWIDTH = ( 20.0 ) INS-28219_BANDCENTER = ( 727.0 ) INS-28219_BANDWIDTH = ( 10.0 ) INS-28220_BANDCENTER = ( 380.0 ) INS-28220_BANDWIDTH = ( 80.0 ) INS-28221_BANDCENTER = ( 910.0 ) INS-28221_BANDWIDTH = ( 80.0 ) INS-28222_BANDCENTER = ( 1015.0 ) INS-28222_BANDWIDTH = ( 130.0 ) INS-28223_BANDCENTER = ( 656.0 ) INS-28223_BANDWIDTH = ( 10.0 ) \begintext Detector Parameters ------------------------------------------------------------------------------ JANUS uses a rectangular CMOS detector, with the following parameters: Parameter Value Notes --------------- -------------------- ------------------------------ Detector size SAMPLES 1504 pixels Each 'Sample' (detector column) is perpendicular to the readout LINES 2000 pixels Each 'Line' (detector row) is parallel to the readout Detector center (752.5, 1000.5) Expressed in pixels in the frame detailed in the section ``JANUS Apparent Field-of-View Layout'' Pixel size 7 micrometers IFOV 15 microradians The values are given in micrometers for PIXEL_SIZE, microradians for IFOV, pixels for PIXEL_SAMPLES, PIXEL_LINES, and for CCD_CENTER. The keywords PIXEL_SAMPLES and PIXEL_LINES respectively correspond to detector columns and rows as described in the User Manual [6]. Although JANUS uses a CMOS sensor, the keyword CCD_CENTER is maintained for historical and compatibility reasons. \begindata INS-28200_PIXEL_SAMPLES = ( 1504 ) INS-28200_PIXEL_LINES = ( 2000 ) INS-28200_PIXEL_SIZE = ( 7 ) INS-28200_CCD_CENTER = ( 752.5, 1000.5 ) INS-28200_IFOV = ( 0.000015 ) \begintext JANUS Field of View Definition ------------------------------------------------------------------------------ The set of assignments in the data section below defines the JANUS FOVs with respect to the corresponding frame to be rectangles with the corners defined by the CMOS sensor and the boresight along the +Z axis. These FOV definitions use angular extent style specification with the cross and along track angular sizes taken from the ``Optics Parameters'' section above. This FOV definition corresponds to the NAIF Body Name: JUICE_JANUS. Please note that the FOV reference and cross angles are defined with half angle values. \begindata INS-28200_FOV_FRAME = 'JUICE_JANUS' INS-28200_FOV_SHAPE = 'RECTANGLE' INS-28200_BORESIGHT = ( 0.000000 0.000000 1.000000 ) INS-28200_FOV_CLASS_SPEC = 'ANGLES' INS-28200_FOV_REF_VECTOR = ( 0.000000 1.000000 0.000000 ) INS-28200_FOV_REF_ANGLE = ( 0.645000 ) INS-28200_FOV_CROSS_ANGLE = ( 0.860000 ) INS-28200_FOV_ANGLE_UNITS = 'DEGREES' \begintext End of IK file.