Version 4.03 update:
Version 4.03 works with IDL 5.4.  Depending on your version of IDL and your operating system some additional editing of the casper_setup file may be required.  The default distributed version assumes IDL 5.4 on a SunOS.  In addition, the following changes have been made:

• A bug in the display of twist angles for C kernel data in the Pointing Information Window has been fixed.
• 3D View has been updated to allow much longer orbital paths to be displayed.  However, beware of taxing your system's memory.
• All software updates identified on the software updates page have been incorporated.

Version 4.02 update:
A new casper_output.pro file allows users to indicate in the CASPER output file if the target is rings and not the body.  This was designed explicitly for Cassini ISS users and may not be useful for other teams.  It is only available through the software updates page.  This addition is not included in the 4.01 release of CASPER.

Summary of Version 4.01 updates:
Version 4.01 of CASPER includes several bug fixes to Version 4.0.

• Several bugs in the C kernel viewer have been fixed.  The save pointing file format has been expanded to include information on the target body and pointing information for field of view corners.  Bugs which resulted in crashes or incorrect output in the save pointing file and the plot pointing tool have been fixed.
• Changes to the BODMOS module by the ISS team have been incorporated.
• PNG save images are now right side up :)

• IVP versions of modules: CASPER 4.0 includes IVP simulation for GENMOSAB, GENMOSCD, GENMOSR, MAPSPA, and TARGET.  CASPER 3.6 included GENMOSAB_IVP and that implementation has been improved in 4.0.  Non-IVP versionsof these modules are included for backwards compatibility only.  Youcan make an inertial observation with the IVP modules, and it is stronglyrecommended that only the IVP versions of these modules be used for newobservation designs.
• Improved link to PDT: All IVP modules listed above can be saved as RequestWorking Files (RWF) which can be read by PDT.  The RWF can be editedwithin PDT and run in PDT to check constraints and to complete or refine the observation design.  Only one observation can be saved to an RWF in this manner at a time.  A separate RWF is required for each observation.
• Improved C kernel data viewing.  The C kernel viewer has been improved. When plotting footprints from a C kernel, it is now possible to use thePointing/Module Info tool (under Utilities in the Target tool) to get detailedpointing information for each selected footprint.  It is now alsopossible to have CASPER plot footprints for each record within the C kernelrather than only at equally spaced time intervals.  Large amountsof pointing data can be saved to an IDL save file from the C kernel viewerwhen plotting the display in Target is not practical.  This pointing data can also be plotted directly from within the C kernel viewer tool.  So, for example, you can get a plot of phase angle as a function of timefrom data in a C kernel.
• LIMBDRIFT deleted: this module is essentially just a special case of GENMOSCD. Rather than maintain LIMBDRIFT and update it to be consistent with theother improved modules, it has been deleted.
• Improved turn model: CASPER now uses a turn time model that more closely simulates what the spacecraft can actually do.  Turn times shouldbe reasonably accurate, but PDT should be used for detailed checking ofobservation times.
• Improved module parameter control: it is now possible to directly enter most module parameters for GENMOSAB, GENMOSCD, GENMOSR, GENMOSP, and MAPSPA.  This includes setting the scan rate which was previously locked into themaximum possible rate.
• It is now possible to save a SkyMap plot as a PostScript file.
• New kernels provided with CASPER version 4.0 include a new version of theT18-5 tour at Saturn.  Unfortunately this kernel reverts to identifying the spacecraft as "CASSINI SIMULATION".  You will need to be sureto specify CASSINI SIM as your observer when using this new file.
• Spacecraft trajectory time tick marks can be switched on in the 3-D Viewtool.
• A shortcut button has been added for deleting the last module in the session.
• A tool has been added which displays an annulus of space centered on theplane which is 90 degrees away from the RAM direction.
• Because the GIF file format is now proprietary, IDL is no longer supporting the capability to read and write GIFs beginning with IDL Version 5.4.  For compatibility, CASPER no longer allows the user to save target plotsas GIFs.  The PNG (Portable Network Graphics) format is used instead.  PostScript and TIFF continue to be supported.
• The HTML version of the User's Guide has been updated for Version 4.0, but the PDF and Word versions have not.  Obsolete versions of theUser's Guide in those formats have therefore been removed from the website.

• Two new modules including target tracking (IVP simulation) capability arenow available in CASPER 3.6.  Additional modules will have this capability in future releases.  This version includes an IVP version of GENMOSAB and a TARGET module with IVP.  For this version, target tracking options are limited to body center and body features (i.e., latitude longitudepoint on the surface).  Help buttons for both modules explain howthey work.
• The BODMOS module more accurately simulates IVP.
• With this version CASPER runs under the linux operating system.
• A bug which occasionally resulted in CASPER crashing when tour kernels were changed has been fixed.
• User-selectable tick marks have been added to the spacecraft trajectory in the 3D-View tool (in MAPSGAP).
• The Printer Setup widget has a Help button explaining configuration ofthe CASPER printers data file.

• See the software updates page for information on two new bug fixes not included in the latest CASPER release.  Updated files can be obtained from the patches directory on the CASPER download page.

Version 3.5.3 update:

• In some situations where the target body subtends a small angle and isnear the north or south celestial pole, previous versions of CASPER could crash in the casper_draw_grid procedure.  This has been fixed, andsome obsolete code has been removed from casper_draw_grid, resulting inchanges to 6 procedures.  That is the only change between version3.5.2 and 3.5.3.
• The MAPSGAP directory now includes a model library for the DEC/Alpha platform.

• An error in the MIMI CHEMS FOV has been corrected.

• An error in GENMOSCD modules with small scan rates has been corrected.
• An error in the GENMOSCD interface which prevented use of overlap has beencorrected.
• The CASPER RWF has been improved to require less modifications once thefile is loaded into PDT.
• The Sun Solaris spice_share file has been changed to make it compatible with more Sun workstation environments.

• CASPER 3.5 release includes cruise and updated tour SP kernels for Cassini,as well as C kernels for ICO1, Venus-2, and Earth.
• Modules have been updated to be consistent with emerging Cassini project module definitions.  GENMOSA and GENMOSB have been replaced with GENMOSAB.  GENMOSC and GENMOSD have been replaced with GENMOSCD.  Previouslysaved GENMOSA, B, C, and D modules can still be read and plotted by CASPER.
• GENMOSP has been updated with new parameters.
• GENMOSR has been added.
• MAPSPA has been added.
• All of the above modules feature an additional output option called a RequestWorking File (RWF).  This file can be read by the Cassini PDT software. This provides a way for observations designed in CASPER to be passed alongto the next program in the sequencing activity (PDT).  This optionis available under the file menu of the Target tool.
• The above module information can also be saved as a CARS Interface File(CIF).  This file will be readable by the CARS software now under development to generate activity requests.  This option is available under the file menu of the Target tool.
• Modules other than GENMOSAB, GENMOSCD, GENMOSP, GENMOSR, and MAPSPA areprovisional pending official definition from the Cassini project.
• The INMS FOV was oriented incorrectly previously.  This has been fixedin the new CASPER INMS I-kernel.
• A VIMS solar port field of view has been added.
• The CDA field of view and articulation has been corrected.
• The RADAR fields of view have been corrected.
• C kernel viewing options have been expanded.  The pointing information tool (found under the utilities menu of the Target tool) now gives moregeometric information for both C kernel footprints and module footprints.
• It is now possible to save pointing information to an IDL save file fromthe C Kernel viewer.  This file includes geometric information for an arbitrary number of pointing instances from a C kernel.
• New spacecraft kernels are included which identify Cassini as Cassini andnot Cassini Simulation.  It should no longer be necessary to use CassiniSimulation as an observer ID, though that option is still available.
• CASPER messages and dialogs with the user now use internal IDL dialog routines.
• The Field of View on Map routine is more flexible.
• The color setup widget has been expanded to a new preferences widget whichallows the user to select how light travel time and aberration corrections are made by CASPER.
• Scan rates may be specified by the user for GENMOSCD.
• A spacecraft kernel file has been added which contains information on maximumand minimum turn rates and accelerations.  This allows easy updatingof turn rate information which CASPER reads and uses in module calculations.
• The on-line User's Guide has been updated.  However, the MSWord and PDF versions of the 3.5 User's Guide are not yet available.