ASTAP is written in Object Pascal and compiled with the Free Pascal Compiler using Lazarus the open source cross platform IDE. 

Executables and source is available at 
    https://sourceforge.net/projects/astap-program/

To compile
For the Windows use the astap.lpi project file.
For the Mac use the astap_mac.lpi project file.
For Linux use the astap_linux.lpi project file.
For the command-line version use /command-line_version/astap_command_line.lpi

{Copyright (C) 2017 by Han Kleijn, www.hnsky.org
 email: han.k.. at...hnsky.org

This Source Code Form is subject to the terms of the Mozilla Public
License, v. 2.0. If a copy of the MPL was not distributed with this
file, You can obtain one at https://mozilla.org/MPL/2.0/.