The Pocket Star Atlas for the Serious Observer

last updated 21 September 2004 (current version: v2.2.1)

Other Software · The PalmAstro FAQ (PalmOS Section) · Beta Testing

WELCOME TO the PleiadAtlas Home Page. PleiadAtlas is a computerized star atlas for personal digital assistants (PDAs) running PalmOS v3.3 and up. Its emphasis is on helping observers to find targets without the aid of computerized telescopes. Accordingly, its strength is its catalogue depth: the full install contains stars down to magnitude 11.5 from the Hipparcos and Tycho-2 catalogues, and just about the entire contents of the Messier, NGC, and IC deep sky catalogues. PleiadAtlas doesn't have to replace your paper atlases--but it can if you need it to.

Besides, you put it in your pocket, which keeps it nice and toasty warm.

Recently Added Features

NEW: PleiadAtlas v2.2 changes the color display from black on white to light on dark. Stars from the Hipparcos database are now shown in colors approximately representing their spectral class. (Field stars are still shown in greyscale.) Also, the databases have been slightly cleaned up to avoid a problem with global text searches on some Palms.

PleiadAtlas v2.2.1 improves the contrast in color mode, and introduces a target crosshatch to help identify the selected object in the maps.

PleiadAtlas v2.1 and later include a Zoom feature that draws a high-power map exactly centered on any selected object. If all databases are installed, this map will include all stars down to magnitude 11.5--a total of 1,457,664 stars. To keep the databases to a minimally manageable size, stars dimmer than magnitude 10.5 are listed simply as magnitude ~11.

Even so, the new version with all databases installed is quite large: a bit over 5.3 megabytes. You can run without the extended field star database (stars between magnitudes 10.5 and 11.5) to save about two megabytes, and without the regular field star database (stars between magnitudes 7.5 and 10.5) to save another two megabytes. Or, alternatively, you can take advantage of another new feature of v2.1--the ability to run PleiadAtlas off a memory card.

If you copy the application and all the databases (including the registration file, if you've registered) to the memory card, PleiadAtlas should run correctly from the card. You should be aware that PalmOS copies the entire application into main memory before starting the program, so you still need 5.3 megabytes (or less if you're running without the bigger databases) of free RAM; what's more, the copying takes a significant amount of time--about 35 seconds on my m500. The advantage is that if you're running other programs from the card, too, those programs can load into memory without PleiadAtlas getting in the way.

Statistics weenies like myself may notice that the main star database (HIPDB.pdb) has a thousand or so more stars than before. This addition includes stars that were omitted from previous versions by mistake: stars that are brighter than magnitude 7.5 but do not appear in the Hipparcos database; and stars that are in the Hipparcos database but were previously omitted because they had no reliable parallax information.

A Comparison with Other Software

I'm pretty sure the other planetarium and atlas programs for PalmOS won't do this, so I will. What follows is my honest, best attempt at characterizing the differences between some similar programs. (Still, just because I say I'm being honest doesn't mean I'm not biased, so take this information for what it is: observations from one of the software writers.) All costs are U.S. dollars.

Program Cost Star Catalogue DSO Catalogue Telescope Control Animation
PleiadAtlas $10 1,450,000 stars to mag 11.5 11,700 DSOs from Messier, NGC/IC, SAC N N
Planetarium $24 9,000 stars to mag 6.5 1,900 DSOs from Messier, Caldwell, etc. Y Y
2sky (Basic) $25 15,560 stars to mag 7 500 DSOs from Messier, Caldwell, etc. N Y
2sky (Total) $40 214,000 stars to mag 9.5 13,600 DSOs from Messier, NGC/IC N Y
2sky (Mega) $50 1,250,000 stars to mag 11.2 13,600 DSOs from Messier, NGC/IC N Y
Star Pilot $10 1,500 stars to magnitude 5 110 DSOs from Messier N Y (redraw)

Planetarium control of your telescope depends on whether a driver exists for your telescope. Check the web site for availability.

2sky Total Download also comes with 2red, which can adjust most but not all programs to use red on black on color displays. It can be turned on or off at your command. Also, I think that the 13,600 DSO figure is slightly inflated, since there is quite a bit of overlap between the NGC and the IC. (But I'm not sure.) As of this writing (September 2004), purchasers of the Basic version will get the full NGC/IC catalogue for free, and purchasers of the Total download will receive a free upgrade to 2sky's million-star Version 3.0 when it comes out this month. No idea how long these offers will last.

Star Pilot has Plus ($20) and Advanced ($30) versions; these add auxiliary programs, which will (for example) show the positions of Jupiter's satellites, or give detailed information about the planets. Check the web site for details.

Operating Requirements

PleiadAtlas will run on any Palm-compatible PDA running PalmOS v3.3 or higher. (It has been tested with some success on versions of PalmOS down to v3.0, but not extensively.) It does not run on the PocketPC or WinCE platforms. PleiadAtlas also needs a significant amount of memory: the full install takes up 5.3 megabytes. If you don't install the field star databases, the memory requirement drops to 3.4 megabytes (with the regular field star database, TYCDB.pdb) or just 1.4 megabytes (with neither of the field star databases). The program won't plot the fainter stars, but it will otherwise work the same.


PleiadAtlas comes as a 4810 kB ZIP file. The ZIP file contains all the files needed to get started, including the ReadMe.txt, which contains the installation instructions. The user's guide is now packaged as a 407 kB PDF, which is also included in the ZIP file.

PleiadAtlas v2.2.1 is nagware. The download version is fully functional; there is only a single reminder page when you first start up the program. (In addition, the About page indicates that your copy is unregistered.) Try it out for as long as you wish. If and when you decide that you like it, you can register your copy of PleiadAtlas, and avoid the reminder page, by paying a registration fee of $10 U.S.; this fee covers the cost of all future updates, too. (So there's no need to hold back, waiting for the next "latest and greatest.") Please send a check or money order, preferably drawn on U.S. funds, to:

Brian Tung
4676 Admiralty Way Suite 1001
Marina del Rey CA 90292

After I receive your payment, I'll send you a registration file by e-mail, which you should install onto your PDA. Be sure to include your e-mail address with your payment.

Problems? Questions? Comments?

Please send all correspondence regarding PleiadAtlas to me at <>.

Copyright (c) 2000-2004 Brian Tung