Planetarium for Palm OS: The Classic Palm Astronomy and Star-Charting App

During the Palm OS era, a small class of software turned handheld organizers into field instruments — and one of the longest-lived examples was Planetarium, a star-charting and celestial-calculation program written by Swiss developer Andreas Hofer and distributed from his own site at aho.ch as well as through PalmGear and Handango. PalmGear catalogued it under product ID 1698, at the historical listing URL palmgear.com/software/showsoftware.cfm?sid=54905620021122082656&prodID=1698. This restored page rebuilds that listing's history using archived copies of the developer's own site, the PalmDB preservation archive, a contemporary astronomy-club newsletter column, and a hands-on Cloudy Nights review — because PalmGear's original page for product 1698 is no longer reachable, and the developer's live site currently shows only a placeholder maintenance message.

Planetarium is a dead product today: development appears to have stopped after version 2.4, and the aho.ch domain that once hosted downloads, manuals, and telescope drivers no longer serves that content. Nothing here should be read as a claim that the software is currently maintained, sold, or safely downloadable from its original home — where we point to files, we point to legitimate preservation archives (PalmDB, the Internet Archive's Wayback Machine) rather than claiming to host anything ourselves.

What Was Planetarium for Palm OS?

Planetarium was a native Palm OS application that plotted the night sky on a handheld's screen and calculated the positions of the Sun, Moon, planets, thousands of stars, and a range of deep-sky objects, comets, and asteroids for any date, time, and geographic location the user entered. The developer's own overview page, archived from December 2002, described it as software for "the beginning star gazer as well as for the professional astronomer" — language that closely tracks how a contemporary astronomy-club write-up characterized the program that same year (see the next section). It offered two main viewing modes: a sky-view screen that rendered a section of the sky against the 88 IAU constellations, and a compass-style view that showed an object's altitude and azimuth the way a physical compass and inclinometer would. A time-step control, driven by the Palm's hardware scroll buttons, let observers advance or rewind the display in increments from one minute to ninety days, which was useful both for planning a session in advance and for watching a planet's motion play out against the background stars.

Beyond charting, Planetarium doubled as a field almanac: it computed twilight times (civil, nautical, and astronomical), lunar phase, rise and set times for any tracked object, sidereal time, and a handful of more specialized figures such as the angular size of Saturn's rings, the positions of Jupiter's four Galilean moons, and local magnetic declination (useful for calibrating a compass when polar-aligning a telescope mount). An observation-log feature let users record notes against objects they had actually viewed, and a location database of roughly 600 world cities meant travelers did not need to look up coordinates by hand.

The Developer: Andreas Hofer and aho.ch

Planetarium was written by Andreas Hofer, a Swiss developer (the domain aho.ch uses Switzerland's country-code TLD) whose contact address for the project was planets@aho.ch. Page metadata on the archived site names him directly as author and copyright holder ("Andreas Hofer," "Andreas Hofer Software"). A 2005-dated Cloudy Nights review describes email correspondence with Hofer as helpful and responsive, which is the only third-party characterization of the developer we found; we have not located a biography, interview, or other primary account of Hofer beyond what the software's own documentation and this one review establish.

The project's home was the /pilotplanets/ section of aho.ch, reachable historically at http://www.aho.ch/pilotplanets/. Wayback Machine captures of that address go back to February 1999, with the earliest surviving capture of the release-notes page dated December 6, 1998, already documenting version 1.4 with prior versions referenced. The site's own changelog states that version 1.3 was "the first one to be released on the web," which pushes the software's actual origin earlier than the oldest surviving snapshot — but no capture of a pre-1.3 release exists in the archive we consulted, so an exact original release date cannot be confirmed from surviving sources.

The PalmGear Listing and Product ID 1698

PalmGear.com, the software storefront this site is reclaiming backlinks from, catalogued Planetarium under product ID 1698, at the historical URL http://palmgear.com/software/showsoftware.cfm?sid=54905620021122082656&prodID=1698. That exact URL is quoted directly in a December 2002 "Computers in Astronomy" newsletter column written by Don Shedrick and archived on a University of Delaware faculty page — the clearest surviving third-party confirmation that PalmGear product 1698 was Planetarium and not a different title.

Note on a naming mix-up: an unrelated Palm astronomy title called StarParty, from developer PFD Systems, was catalogued by PalmGear under a completely different product ID — 35445 — and is a different kind of program (an observing-list and Celestron NexStar GoTo companion, not a star-charting planetarium). The same December 2002 newsletter column lists both product IDs side by side, which is how this restoration confirmed that PalmGear ID 1698 belongs to Planetarium, not StarParty. Earlier internal notes on this site had conflated the two; that mix-up has been corrected here.

PalmGear's own product page for ID 1698 is no longer reachable — the domain now serves unrelated content or nothing at all for that path — so this restoration relies on the newsletter column's direct citation of the URL, plus PalmDB's independent hosting of the same software under the title "Planetarium," to establish the identification.

Version History

The fullest surviving version record comes from the developer's own "release information" and "what's new" pages, captured repeatedly by the Wayback Machine between 1998 and 2007. Version numbering ran from at least 1.3 up through 2.4, the last version documented in any surviving snapshot or preservation archive. The table below reconstructs the timeline from those captures; entries without a confirmed date are marked accordingly.

PalmDB's current file archive lists installers for versions 2.4, 2.2.2, 1.9, and 1.8 specifically (file sizes: planet24.zip 1.1 MB, an associated gpsplugins.zip 12 KB, an optional extended star database plnstars16.zip at 38 MB, planet22.zip 268 KB, planet19.zip 104 KB, and planetarium1.8.zip 52 KB). Note that PalmDB's version label "2.2.2" and the developer's own changelog headings ("2.2," "2.3.0," "2.3.1") do not line up perfectly one-to-one; we present both without resolving the discrepancy, since we could not find a single authoritative version list that reconciles them.

Palm OS and Device Compatibility

The developer's 2002-era overview page stated that Planetarium ran on PalmOS 2.0 or later, used gray shading on PalmOS 3.0 and up, and used color on color-capable devices. That broad claim, however, predates the PalmOS 5 transition. The site's own FAQ page — captured in 2007 but addressing problems that arose as users moved to PalmOS 5 hardware — states plainly that older Planetarium versions were not compatible with PalmOS 5, and that a full reinstall (delete, then reinstall, not just install-over) was sometimes needed after switching devices. PalmDB's crowd-sourced compatibility tags for the software list OS versions 3.5, 4.0, 5.0, and 5.4, which is broadly consistent with a program that started on very old PalmOS releases and was actively updated through the PalmOS 5 era.

Device-specific quirks are documented directly by the developer. One notable example: Sony CLIÉ PEG-NR70 users saw the program install and run correctly but crash with a fatal exception on exit — a bug the FAQ attributes to Sony's OS build, worked around by enabling the "High Resolution Assist" option in the CLIÉ's own Preferences application. Full support for early hi-res+ 320×320 screens (named examples: Sony CLIÉ NR70 and UX50, Palm Tungsten T3, Garmin iQue 3600) was added specifically in version 2.3, according to the developer's changelog — meaning earlier versions on those devices likely ran at lower effective resolution or with display quirks.

The telescope-connectivity manual page (see below) separately lists which Palm-family devices carry a physical serial port versus Bluetooth, since that distinction governs whether a given handheld can drive an external telescope at all:

Screen and memory footprint: the developer's 2002 specification page cites a minimum memory requirement of 144 KB (more with additional installed databases) and a claimed typical calculation accuracy of 0.1 degrees. Both figures are the developer's own stated specifications; we found no independent benchmark or third-party measurement confirming the accuracy claim, so it should be treated as a manufacturer specification rather than an independently verified figure.

Star Charts and Sky View

The sky-view screen rendered stars, planets, and (optionally) constellation lines and boundaries across an adjustable field of view. The Cloudy Nights review, written by an amateur astronomer who used the software over roughly a two-year span in the early-to-mid 2000s, gives the most concrete usage detail available: field of view was adjustable from 180 degrees down to about 1 degree in numerous steps, letting an observer match the display to a finderscope's actual field; selecting an object drew Telrad-style alignment circles (0.5°, 2°, and 4°) around it; and version 2.4 added a magnitude-limit control in the toolbar so users could raise or lower the faintest stars shown at each zoom level independently. That same 2.4 changelog entry also states the built-in star database is the Yale Bright Star Catalogue — a real, published catalog of naked-eye-visible stars complete to roughly magnitude 6.5 — which corroborates, from the developer's own release notes rather than secondhand summary, the oft-repeated claim that Planetarium's base install covered "up to 9,000 stars" to about that magnitude limit. The Cloudy Nights review independently cites an exact figure of 9,096 stars in the standard install, consistent with the Yale catalog's known size.

Later versions decoupled the star catalog from the base program: version 2.3 made the application a single installable file that could be relocated to an SD/memory card, and version 2.4 introduced separately downloadable, larger star databases — built from the Hipparcos and Tycho-2 satellite catalogs — reaching down to roughly magnitude 12 for users with enough free memory to install them (PalmDB's archive still hosts one such database file, 38 MB, alongside the 1.1 MB base program).

Orientation and display options included an invertible (white-on-black) sky view intended for use with a device's backlight at night, a true night-vision mode using red-on-black rendering on color screens, and — for monochrome devices without a red-light mode — a checkbox to invert to a black background as a lower-glare alternative. The developer's FAQ page candidly notes a hardware limitation rather than a software one: color Palm devices of the era had a thin strip of white backlight bleed visible around the screen bezel even in night mode, which no software setting could fully eliminate; the FAQ suggests taping red transparency film over the screen as a workaround, and the Cloudy Nights reviewer independently reports doing exactly that.

The Celestial Object Database

Planetarium tracked several distinct classes of object, each drawing on a different underlying data set:

All three editable lists — locations, user objects, and comets/asteroids — were implemented as separate Palm databases that synced during HotSync, and each supported export to, and import from, the Palm Desktop Memo Pad. That mechanism doubled as a rudimentary sharing feature: a user could beam a memo of favorite deep-sky targets to a friend, or paste a list of telescope alignment stars copied from a web page into a memo and import it directly into the program.

Observing Tools: Rise/Set, Twilight, and Moon Phase

Beyond the sky map itself, Planetarium functioned as a compact almanac. For any selected object it could display right ascension/declination and altitude/azimuth coordinates, rise and set times, and — for the Sun and Moon specifically — a dedicated twilight screen giving civil, nautical, and astronomical twilight times along with day length and its change from the previous day. Lunar phase was shown graphically in the compass view at all times, not only when the Moon was the selected object, so an observer could check at a glance whether moonlight would interfere with a planned deep-sky session. A meteor-shower screen listed the year's showers and highlighted whichever was currently active, plotting the shower's radiant as a line in the sky view when enabled. The program could also serve as a rough sun-and-shadow compass during daylight — lining up the on-screen Sun symbol with the real Sun indicated true north — and as a magnetic-declination reference for calibrating a physical compass, a feature the Cloudy Nights reviewer specifically used for polar-aligning an equatorial mount when Polaris was obstructed.

Telescope Connectivity

Planetarium supported two tiers of telescope interaction. The simplest required no cable at all: tapping any object on the sky map displayed its altitude/azimuth or RA/Dec coordinates, which an observer could then dial in manually on a telescope's own setting circles — a workflow the Cloudy Nights review describes using extensively with home-built digital setting circles on a Dobsonian mount.

For computerized ("GoTo") telescopes, the developer published separate driver files supporting a specific, named list of telescope control protocols rather than universal compatibility:

• Serial-cable drivers: Meade LX200 and ETX; Celestron NexStar 5, 8, 4/60/80/114GT, N8GPS, N11GPS, and Ultima; SkyCommander and ServoCAT digital setting-circle systems; Losmandy Gemini.
• Bluetooth drivers (added later, requiring a separate Bluetooth-to-serial converter such as the AIRcable unit the developer specifically tested): Meade LX200/ETX and Celestron NexStar only — a smaller subset than the wired driver list.

Two functions were available once a driver was installed: "Query Position," which asked the telescope where it was currently pointed and marked that spot on the sky map, and "Set Position," which commanded a GoTo-capable telescope to slew to whatever object was selected on the map. The developer's manual is emphatic that the telescope must be connected through its own AutoStar or hand-controller unit, never wired directly to the Palm's serial port, warning that a direct connection risked damaging either device. It also documents a specific hardware bug on the Palm Tungsten T3, whose serial-port firmware incorrectly demanded a hardware-handshake signal the telescope side never provided — worked around either with a third-party utility called SerialFix or a small solder-your-own adapter looping the T3's own RTS line back into its CTS input.

A plain HotSync cable was explicitly called out as unsuitable for telescope use: many Palm devices' serial ports used low digital voltage levels requiring a powered level-converter circuit built into the cable, and standard HotSync cables drew that power from the PC side rather than the Palm, so a purpose-built, Palm-side-powered serial cable (plus, depending on the exact cable, a null modem and gender changer) was needed for a working telescope link.

GPS and Location Data

A separate downloadable GPS plug-in let Planetarium read location directly from a GPS receiver over the serial port rather than requiring manual coordinate entry, supporting devices that output standard NMEA sentences as well as a dedicated plug-in for the Navman GPS 500. The developer's documentation lists specific units it had been tested against — several Garmin models (eTrex, eTrex Summit, eMap, GPS12, 90 GPS, GPSMAP 195, 12XL, GPS II+, GPS III+) and several Magellan/Rand McNally models — and notes that a DeLorme Tripmate worked only indirectly, through DeLorme's own Solus Pro software first, and that a DeLorme Earthmate did not work at all without an additional third-party NMEA converter. This is a good example of a compatibility claim that is real but bounded: GPS support existed and was field-tested, but only against a specific, named list of hardware rather than "any GPS receiver."

Price, Licensing, and Where It Was Sold

Planetarium was shareware: a fully functional trial could be downloaded and used for free, with an increasingly frequent reminder screen nagging the user to register over time. A single registration key, once purchased, was stated to work with all future versions of the program — no repurchasing on upgrade.

Two independent snapshots give two different prices, which we read as a genuine price change over time rather than a conflict to resolve in favor of one: an archived registration page from April 1999 lists the price as $19, payable through a reseller called PilotGear (by phone, fax, email, or an online storefront hosted on Viaweb); the Cloudy Nights review, whose page metadata indicates a 2005 update date, states the price by then was $24. We could not find a snapshot pinning down exactly when the price changed. Separately, the developer's own FAQ page (captured in 2007) directs registration and billing questions to "PalmGear.com or Handango.com" rather than PilotGear, indicating the retail channel changed at some point between 1999 and the mid-2000s; we did not find a source confirming whether PilotGear and PalmGear were related businesses or simply sequential, unrelated resellers, so we make no claim either way.

The program was also localized: German and French versions existed for at least some releases (both are present in the earliest surviving 1998 snapshot, alongside the English original), though by the December 2002 download page only English and German builds were still being offered as current downloads, with a French build listed under "older versions."

Why Palm Hardware Appealed to Amateur Astronomers

Neither the developer's site nor the reviews we found offer an explicit essay on this question, but the Cloudy Nights review makes the underlying motivation concrete through the author's own account: the alternative to a Palm at the eyepiece was a full astronomy program running on a laptop, and the reviewer specifically describes bringing a laptop out to a dark-sky eyepiece as inconvenient for the observer and hard on the laptop itself (exposure to dew and cold). A Palm device, by contrast, could be held in one hand and operated with a stylus rather than a keyboard and mouse, ran for long stretches on Palm OS's typically modest power draw, and could be pulled out of a pocket already synced with the observer's saved locations and observing log rather than needing to be booted. The same review frames Planetarium's portability as enabling an observer to "eliminate" a separate star atlas, paper logbook, laptop, and folding table from their observing kit — a first-person testimonial to the appeal of PDA-based astronomy software rather than a claim we can independently verify, but a useful and concrete illustration of why this category of software existed at all.

Planetarium vs. Other Palm OS Astronomy Software

Planetarium was one of several astronomy titles available for Palm OS, and the same December 2002 newsletter column that confirms PalmGear product ID 1698 also profiles three others side by side, which lets us compare them on the same terms the original article used rather than guessing at differences:

The Cloudy Nights reviewer, notably, states outright that the review makes no comparison with other PDA-based astronomy programs, so none of the head-to-head framing above comes from that source — it is drawn entirely from the 2002 newsletter column and from each program's own developer documentation.

Contemporary Reviews and Recognition

The most substantial hands-on account we located is "Using Planetarium for the Palm Pilot, Astronomy Software at the Eyepiece," a first-person review by amateur astronomer Steve Childers of Winston-Salem, North Carolina, published on Cloudy Nights (page metadata shows a September 2005 update date; internal references to "the 2003 Messier Marathon" and to having used the software "for over a year" suggest it was substantially written sometime in 2003–2004). Childers used Planetarium extensively with home-built digital setting circles on a 10-inch Dobsonian, praised the automatic observation log and the twilight/Moon-phase screen, and reported successfully locating 100 Messier objects in a single night at the 2003 Messier Marathon using the program's zoomable sky view alone. His stated criticisms were aimed almost entirely at Palm hardware rather than the software — screen glare from a device's backlight leaking around the bezel even in the program's own night-vision mode, and small on-screen icons being hard to read outdoors.

The developer's own site (December 2002 snapshot) lists several period recognitions, which we report as claims made on the developer's own page rather than facts we independently confirmed: a nomination for the 1999 Shareware Industry Awards, inclusion in the 2000 ZDNet PDA Software Awards, a "Softwaretipp" feature on the German PDA site pdassi.de, a user-voted "Coolest" award from the review site eurocool.com, and a "Key Resource" listing from the web directory Links2Go under its Astronomical Programs topic.

Current Status: What Survives Today

As of this research, the live aho.ch domain no longer serves the Planetarium project pages at all: requests to the historical /pilotplanets/ paths return only a bare placeholder reading "maintenance," served with modern infrastructure (a Cloudflare analytics beacon) that has nothing to do with the original late-1990s/2000s site. We cannot confirm from available sources whether Andreas Hofer still controls the domain, whether it changed hands, or when the original content was taken down — only that it is gone as of now and that Wayback Machine snapshots are the only way to see the original pages.

PalmDB.net independently preserves installer files for versions 1.8, 1.9, 2.2.2, and 2.4, along with the GPS plug-in package and an extended star-database file, and links back to a December 2012 Wayback Machine snapshot of the original site as its reference "project page." For anyone wanting to explore the software's original documentation, manuals, or download files today, PalmDB.net and the Wayback Machine are the legitimate places to look — this page does not host or mirror any of that software itself.

Frequently Asked Questions

Key Takeaways

• PalmGear product ID 1698 was Planetarium, a star-charting and celestial-calculation app by Swiss developer Andreas Hofer — not StarParty (PalmGear ID 35445), a different, unrelated program by PFD Systems that earlier internal notes had mistakenly conflated with it.
• Development ran from at least version 1.3 (undated) through version 2.4, the last version documented in surviving archives, with the most precisely dated release being version 1.9.2 on November 11, 1999.
• The base star database was the Yale Bright Star Catalogue (roughly 9,000–9,096 stars to about magnitude 6.5); optional Hipparcos/Tycho-2-derived downloads in version 2.4 extended coverage toward magnitude 12.
• Standard deep-sky coverage was the 110 Messier and 110 Caldwell catalogs, with optional downloads adding 280 double stars and the 400-object Herschel/NGC list.
• Telescope control was real but bounded to a named list of protocols — Meade LX200/ETX, Celestron NexStar, SkyCommander, ServoCAT, and Losmandy Gemini — over serial cable, with Bluetooth added later for a narrower subset (Meade and Celestron only).
• Documented device compatibility spanned the original PalmPilot and Palm III/V series through Tungsten, Treo, Handspring Visor, and Sony CLIÉ hardware, with specific fixes noted for the CLIÉ PEG-NR70 and the Tungsten T3's serial-handshake bug.
• Pricing moved from $19 (1999) to $24 (by 2005) as shareware; the retail channel shifted from an early reseller called PilotGear to PalmGear.com and Handango.com by the mid-2000s.
• The original aho.ch project pages are gone — the live domain now shows only a maintenance placeholder — and the Wayback Machine and PalmDB.net are the only verified surviving sources for the software and its documentation today.