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Looking for information about the Chang'e 5-T1 rocket booster hitting the far side of the moon? Click here (or click here for comments on the initial (mis)identification, or here for comments on the imaging of the resulting crater)

CHARON astrometry software Find_Orb Index
Contact info Jovian events GSC-ACT
Assorted calendar systems Astronomical Glossary C/C++ source code
On-line orbit determination Current NEOCP summary Miscellaneous orbital elements
On-line satellite ID PDCursesMod library PSudoku puzzle generator
Easter dates/patterns Guide user manual (HTML) Guide user manual (PDF)
Asteroid observer tools Privacy policy

Click here to search the Project Pluto site

Guide 9.1 is now shipping. Click here for information.

If you already have the Guide 9.0 DVD, click here for your free update to Guide 9.1.

This update includes a few improvements and bug fixes to the software, and is highly recommended.

This site last updated 2017 May 8.

Pagine in italiano su questo sito Web / Pages in Italian on this site

About Project Pluto: Project Pluto supplies astronomical software, both commercial and freeware, to amateur and professional astronomers. The foremost product is the Guide DVD Star Chart, a powerful general-purpose charting/desktop planetarium tool. The main purpose of this program is star chart generation, and it is unsurpassed in this area; but it also provides immense amounts of data on the objects displayed, ephemerides, telescope control, and other useful features.

The Find_Orb orbit determination software can take a set of positional measurements of an asteroid, comet, or natural or artificial satellite, and determine its orbit.

Very useful! Mailing list for Guide users!

Click here for a Japanese version of parts of this site.

Click here for an HTML version of the Guide users manual.

There is a list of particularly interesting events to simulate using Guide.

Some information about the precision of planetary positions and other aspects of Guide is available.

Some people who have seen the current support for the above languages have asked about adding more. Some information on translations has been added to this site.

Some data on custom telescope control (complete with correction for mechanical errors) through Guide is available here.

Where Guide users are: (22 Jun 1999) Click here for a world map showing where Guide is used. (There's also a map showing where Guide is used in the United States.)

The background shading shows the path of the August 1999 solar eclipse, since Guide's "geographic display" was really added for only the purpose of showing eclipses and occultations. But the orange symbols give a rough idea as to where Guide users are.

If you're a current Guide user and would like to display this dataset on Guide charts, click here. (Given the file at that link, you will be able to zoom in for greater detail.) The dataset/chart was built out of both pure curiosity and as an example of how "user-added datasets" work on geographical data.

As the above chart shows, there is currently a Guide user at the Davis Station in Antarctica, as well as one at the South Pole research station, so Guide is now used on all continents. About half of Guide users are in the US and Canada, with a lot of users in Western Europe, Australia, and Japan, plus a few scattered throughout the rest of the world (there is one user each in Tahiti, New Guinea, Siberia, Iran, and Pakistan, for example). Oddly enough, while there are a few dozen users in Hong Kong and South Africa, there are none at all (so far) in the rest of Africa or in mainland China.

Contact information

Project Pluto
168 Ridge Road
Bowdoinham ME 04008
tel (207) 666 5750
tel (800) 777 5886 (1-800-PR-PLUTO)
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Copyright 1996-2016 Project Pluto.