The last two versions of C2A for Windows are available for download in case of a regression. It is advised to install the latest version.

Most recent Version

New features in version 2.0.33
The Internet connection is tested before it is accessed by C2A.
An option is added to automatically display asteroid and comet positions after a filter is applied.
Asteroid and comet management has been improved.
A "landmark" (i.e. a simple cross) can be associated to any object in the maps in order to improve its visibility and access. The landmark can be added using the contextual menu (mouse right button) and can be deleted using the Edition menu. Going to the current landmark can also be done using the Edition menu.
The Moon age is now computed and displayed (simply position the mouse cursor on the Moon icon in the dialog zone at the bottom of the screen).
Star and Deep Sky magnitude filters have been improved. It is now possible to adjust the magnitude filters whatever is the zoom level using the small "+" and "-" buttons in the dialog zone at the bottom of the screen. Using these button while pressing the Ctrl key applies the changes to the Deep Sky objets, otherwise to the stars. A mouse click with the right button restore the default magnitude filters.
The current Star and Deep Sky magnitude filter values are now displayed at the bottom right corner of the main screen.
An option has been added so that Horar Angles can be displayed in the 0/24 Hours interval in the information window. This option is accessible in the Misc tab of the options dialog box.
The icons of the program have been modified to allow a better display under Windows Vista.

Version Before Latest Version

New features in version 2.0.32
The user can now define its own horizon profiles and display them in the maps. An example is provided into the C2A installation directory (file UserHorizonUS.txt) and the syntax is described in this example file. Note that the syntax is the same as the one used in the Occult Watcher program. Once the file is defined, the file name as well as the profile name must be declared into the Field tab of the Options dialog box.
The satellite positions of Mars, Jupiter, Saturn and Uranus are displayed in the maps assuming the zoom level is high enough. The display is performed only on the 1995-2020 period. Position calculation is perfomed using the IMCCE coefficients.
The Julian Day as well as the Sideral Time are now displayed in the main window information zone at the bottom of the screen.
It is now possible to select a second list of reference stars to display the Polar field at a given time and facilitate the polar alignment of a mount (the type of reference stars to be displayed is made in the Telescope option dialog box).
A new function called "Polar Clock" has been added in the Telescope menu. It allows the user to produce a PDF file where all the polar reference stars are displayed at different times during the night. The objective is to print this document and bring it to an an observation session in order to facilitate the polar alignement of a mount.
When printing maps in black and white using the highest contrast options, the stars are now filled with the back rather than a 72 gray.
It is now possible to display an FFT view of a periodic error plot in order to faciliate the identification of the main periods.
The position of the child windows are better memorized from session to session.
Some incorrect spectral types have been fixed in the SAO star database. Furthermore, the complete spectral type is displayed when identifying the brightest SAO stars.
The HR (Harvard Revised Number) and HD (Henry Draper) numbers are now displayed for the brightest SAO stars.
A new function has been added in order to easily import updated orbital elements for asteroids and comets through Internet. All what the user has to do is to click the button "Auto Import" into the Asteroids & Comets tool.

In order to install the C2A for Windows distribution on your system, extract the contents of the ZIP archive in a temporary directory and run the setup.exe executable. Then simply follow the installation steps as displayed on the screen. Please be aware that the Windows installation procedure (but nor the software itself) is in French, which should not be a problem considering it is a very basic installation.

If a previous version of C2A for Windows is already installed on your system, uninstall it first using the Windows Configuration Panel. Then install the new version. Your settings will not be lost.

Polynome File to Compute Planetary Positions between 1900 and 2100

UCAC2 Bright Star Supplement

Add-in to Use C2A with Occult Watcher

Pre-release 1.4
Size is 13 kBytes

Occult Watcher is a software designed to easily manage predictions of star occultation by asteroids. An Add-in is available to directly launch C2A from Occult Watcher and display a map of the occultation (setting automatically the time, location and catalogue for the considered event). The Hipparcos and UCAC2 catalogues are often used in occultation predictions, so it is necessary to have them installed on your computer before using this Add-in. See the Catalogues page to download the Hipparcos catalogue and the Tools page to get the UCAC2 catalogue compiler for C2A.

Caution! In order to use this C2A Add-in for Occult Watcher, you need at least version 2.0.31 of C2A and the most recent version of Occult Watcher.

To install the Add-in, simply extract the file OccultWatcher.C2a.dll (available in the ZIP file) and copy it into the Occult Watcher installation folder. A C2A entry will then be added in the Occult Watcher Add-in menu. To launch C2A and get the map of an event, select this event in the Occult Watcher list and go into the "Add-in" menu to create the C2A Occultation Map.

New features in version 1.4 are the following:
Prepoint Track is supported
A single instance of C2A is used to display maps.
NOMAD catalog usage can be forced trhough an option in the Add-in.
French and English are the two supported languages (language is set through the Occult Watcher Help menu).
It is now possible to select the type of map to be displayed
UTC Offset and Daylight Saving Time are now automatically adjusted for the event.