The links below are of a general nature and possibly of interest to other amateur astronomers with an historical interest. It is always worth looking at Michael Boschat's huge page of astronomy links - which he must spend ages keeping up to date. Chris Marriott has provided a freeware version of his new Skymap Pro 5 software. The Preview version has limited databases: 30,000 stars down to Magnitude 7.5, and 10,000 deep space objects, together with some asteroids and comets. There is no time limitation on this fully functional program. A very useful feature of the preview version is the display of planets, including the satellites of the planets. You can check the position of Jupiter's moons by finding Jupiter and zooming in. -December 1998 A couple of Excel spreadsheets have appeared in recent weeks. Kevin Williams has provided a simple star map spreadsheet ( starmap3, 800Kb) based on the yale bright star list. His map needs Excel 97 to work, as it uses the 'bubble diagram' variant on the simple scatter diagram to display his stars with sizes depending on the magnitude. -November 1998 Brian Workman has provided a Binary star calculator based on the 'Fourth Catalog of Orbits of Visual Binary Stars'. You can select a range of binary stars from a pivot table and then copy the details to another sheet to find the current separation and position angle. A graph also shows the orbit with marked points for the years. Tom Polakis has put this sheet up on a Web page, and the Workbook loads into Excel 95 fine. -November 1998 The Online Simulator is a page which will generate a simple horizon map for your longitude, latitude and time zone. The map can be saved as a GIF bitmap file or as PostScript. The PostScript version has the same dark colours as the GIF and won't load into CorelDraw 6, but will load into Adobe Distiller. -October 1998 The Online Map Creation page is a page which will generate maps of the world in a variety of projections and formats including GIFs and Adobe Illustrator files. The Illustrator files will load into CorelDraw from version 4 upwards provided you change the .AI extension to .ART. This page has proved most useful! -October 1998 Free Pascal by Michaël Van Canneyt, Florian Klämpfl and others is, well, a free pascal compiler for DOS, which works under win95 and interfaces with the TextPad editor. Takes less than 5 Mb of drive space, allows extensions to the ANSI standard including 'units' and appears solid. -August 1998 If you are interested in the history of astronomical calculation, Nicholas Kollerstrom and Joe Cain have provided an excellent Web site on Newton's lunar theory, with plenty of background, and downloadable spreadsheets. -July 1998 If you suddenly need to remind yourself about Chebyshev polynomials, or need some code to generate a special function, the Numerical Recipes in C book is available online in Adobe Acrobat format. One of the authors of Numerical Recipes is William Press, who teaches astronomy. His lecture notes are available online, and include a good derivation of the two body orbit from Newton's laws. -June 1998 If you need a simple freeware planatarium program (with no direct printing facilities), then John Walker's Home Planet (win95) may fit the bill. John Walker developed AutoCAD, but Home Planet does not use LISP at all for anything, althrough it does include a cukoo clock. Source.