.KEYWORD stars
.FLYINGHEAD TO INFINITY AND BEYOND
.TITLE Piloting your Palm computer to the stars!
.OTHER
.SUMMARY Every month, we’re reminded just how versatile the little Palm computer really is. This month, Keith Johnson, Associate Director of the Fleischmann Planetarium, shows you how you can use your Palm organizer and a few add-on applications to track the Sun, the Moon, and the stars. Combine the backlight display and amazing portability of the Palm computer with the applications Keith describes, and when your son or daughter asks you about that bright light in the sky, you’ll be able to provide all the interesting answers.
.AUTHOR Keith Johnson
We Palm computer users have known for a long time that our gadgets are out of this world. But we now have some excellent applications that can tell us what’s happening in the sky. If the Three Wise Men had carried Palm computers equipped with some of these astronomical programs, they might not have arrived two years late! They (the applications, not the wise men) are all available at PilotGear and other archive sites. Most are shareware, but a couple of them are freeware.
.H1 Solar system software
Early astronomers first looked at the obvious celestial bodies, the sun and the moon, before looking further. This was, in part, due to the limitations of the most common early astronomical tool: the human eye. In this section, we look at software that helps you look at the solar system.
.H2 Sun!
Ed Wilborne is the most prolific of the astronomical programmers, and we’ll look at three of his programs. Sun! tells you the times of sunrise, sunset, transit (when the sun is due south, or local noon), and the beginning and end of three kinds of twilight, as shown in Figure A.
.FIG A Sun! provides a lot of information about the Sun’s behavior in a small space!
As with all of Wilborne’s programs, and most astronomical applications discussed here, you can set the date, time, and observing location. You’ll need a couple of auxiliary applications to aid in the calculations, but Wilborne provides copies of these in his package. There is a version of Sun! available for a Windows desktop machine, too. Sun! is shareware; the fee is $5.
.H2 Moon!
This companion to Sun! gives you rise, set, and transit times, plus distance, for the moon. This application is slower than Sun! — it takes the Palm computer nearly 20 seconds to grind through the math — but the moon’s orbit is complicated (it’s the only body that ever gave Isaac Newton headaches when he tried to calculate its path). This is probably why the shareware fee for Moon! is $10.
.H2 J-Moons!
J-Moons! fills a special niche. If you’re ever out at the telescope looking at Jupiter’s four large moons, and a friend asks you which one is which, you can use this application to find out, as shown in Figure B. It will even flip the display over in case your telescope gives you a reversed view. The fee for J-Moons! is $5.
.FIG B J-Moons!’ display shows you where the moons Callisto, Europa, Io, and Ganymede are for a chosen day and time.
Sun!, Moon!, and J-Moons! are also available as a package called AstroPak, with a shareware fee of $17.95. For a bigger bundle, see the notice below under "StarPilot".
I’ve compared Wilborne’s results with the results of a desktop computer application, and they check out very well. Actually, all of the programs mentioned here provide adequate accuracy for all but the most discriminating observer. And no, I don’t know what the exclamation points in Wilborne’s program titles signify.
.H2 Moon
Stargazers are generally interested in the phase of the moon. A thin crescent moon is a delight to see, while a bright Full Moon will wash out everything else in the sky and render observing impossible. Alex Garza’s application draws a calendar for the month with a small graphic of the phase for each day. By tapping on a graphic, you find out exactly how old (how far past New phase) the moon is on that day. Garza provides information about terms and definitions for the beginner. An added bonus: the day view gives you the Julian day, a number which is used in many astronomical tables. Moon’s shareware fee is $5.
.H2 Moon Phase
Steven Kienle takes a different angle on the problem. Moon Phase draws a large (well, large for the Palm computer) graphic of the current moon, like the one in Figure C.
.FIG C Moon Phase displays a graphic of the current phase of the Moon, and a table of dates for the next four major phases.
You can step forward or backward a day at a time; you can also select whatever date you wish to see. Dates for the next four main phases (New, First Quarter, Full, Last Quarter, though Kienle labels them in a different, non-standard way) are shown at the bottom, and selecting one of those goes directly to that date. Kienle also provides plenty of explanatory help. This application is freeware.
.H2 Astro Info
There are many ways to skin a Leo [Denise, who is a Leo, read that and yelled "Hey!" — DG], and Michael Heinz provides a lot of data in table form for the main solar system bodies. You get rise and set times, but also local positions in the sky (altitude and azimuth) as well as celestial coordinates (right ascension and declination). Heinz includes a routine to convert local clock time to sidereal (star) time for the serious stargazers. Astro Info is freeware.
.H1 Star chart programs
Once the telescope came into vogue, we humans began to look beyond the solar system and to the stars. You can too, by using the programs described below.
.H2 StarPilot
If you’ve ever used one of those two-dimensional circular maps of the sky, Figure D will look familiar. StarPilot plots both stars and solar system objects on a chart of the entire sky for a chosen date and time. But, unlike the paper charts, this program allows you to adjust the display in various ways. You can set the display for any date, time, or location.
.FIG D The main screen in StarPilot is a circular star chart familiar to beginning star-gazers. You can adjust how many stars are displayed.
You can even set the limiting magnitude (i.e., how faint a star you want to have plotted). The authors include two handy buttons labeled "Rural" and "City," and the difference between the two is significant. You have many more stars in the rural view, but it takes considerably longer to plot.
You can choose which planets (as well as the Sun and Moon) to display. Solar system bodies are symbolized by small letters to distinguish them from stars. With the magnifier pointer, you can magnify the view of a small area of the chart, with or without lines connecting the stars in the constellations (and you can choose the magnification factor). See Figure E for an example.
.FIG E StarPilot’s zoom function will magnify a chosen area from 2 to 10 times.
Using a third pointer to select an object will give you information about its name, what type of star or planet it is, and how far away it is. Other features let you find a star or constellation by name, and flip the chart for use at your telescope. StarPilot manages to successfully cram a lot of graphical information into a pretty small screen.
The fee for StarPilot is $30. StarPilot, Sun!, Moon!, and J-Moons! are also available as a package called StarPilot Plus for $44.95. The latest versions allow you to directly jump from StarPilot to the other three and back again without going to the Palm device’s application menu.
.H2 Planetarium
Andreas Hofer wasn’t content to take onedifferent tack with this application: he took a couple! One of the two views in Planetarium, shown in Figure F, offers a two-dimensional flat rectangular star chart of a part of the sky, with constellation lines and planets included at your option. This is similar to charts in typical astronomy textbooks, but is more interactive and dynamic.
.FIG F The horizontal line in this graphic of Planetarium’s "S" view is the horizon (seems fitting somehow, right?). Stars are symbolized by dots of different sizes. The two unusual symbols stand for Saturn and Jupiter.
The other view format is unique to this program, as far as I know, and offers an interesting way to visualize where objects are in the current sky. In Figure G, Hofer draws a circle like a compass rose, and plots solar system objects along the circumference according to their compass directions. On a half-circle to the side, he plots the altitude (e.g., the distance in degrees above or below the horizon) of each object. For one object of your choice, he adds data in two kinds of celestial coordinate systems, plus the current distance from Earth. Finally, the current appearance of the Moon is shown, phase and all.
.FIG G Planetarium’s "C" view plots the altitudes of solar-system objects on the left, and azimuths (compass directions) on the right.
There’s a lot of information available in Planetarium, but it’s displayed well with very little clutter. For instance, the program uses traditional celestial symbols for the planets rather than names, so that everything will fit. Fortunately, one of the help sections includes a chart of the symbols, helpful for those of us who are astronomers rather than astrologers (yes, there IS a difference!).
One of the most interesting features in Planetarium is its use of time. You can use the Palm computer’s hardware buttons to advance forward one step at a time. Hofer has carefully chosen his time intervals so that you can, for example, follow the annual path of a planet among the stars, including retrograde motion and conjunctions. It’s even possible to get a rough idea of the circumstances of solar eclipses. Planetarium has a fee of $16.
.H2 Palm Globe
This application is actually the exact opposite of a star chart program, but it seems to fit under this heading nevertheless. Instead of showing you the sky as seen from Earth, Palm Globe shows you the Earth as seen from space. A sample graphic can be seen in Figure H. Author Mike Cowlishaw has included a number of controls to let you view our globe from different angles, and under different types of lighting. If you don’t understand why the sun is up for 24 hours a day at the North Pole in the summer, this program may give you some help. Palm Globe is freeware.
.FIG H Palm Globe draws the Earth as seen from space in a variety of formats.
.PAGE
.H1 Other astronomy aids
In addition to stand-alone applications, there are many other aids to astronomical Palm computer use.
AstroPilot is an electronic reference book on astronomy. It is basically a set of Doc files and images, including a set of monthly star charts, a glossary of astronomical terms, a list of the 1000 brightest stars with information about each one, and a list of astronomy Web links. The package takes up more than 185K of memory; I found it a bit large for information I could store on my desktop computer, but you may find it useful the next time you’re abducted by aliens. You may also have more memory than my 1MB PalmPilot Professional! AstroPilot costs $15.
Ed Wilborne has written a function for Russ Webb’s RPN calculator to compute various kinds of data about the moon. There is a Doc file listing all sorts of data about the planets (surface gravity, orbit size, length of day, etc.). There are database files of the extragalactic Messier objects. There are Doc files on the Apollo missions, the Mars missions, and probably about upcoming Pluto missions.
And, of course, all dedicated spacefaring Palm computer users absolutely must have a copy of Jeff Jetton’s "Tricorder" application…
Just search the usual Palm computer online archives in the "Science/Math" or "Misc/Fun" sections, and you can become a Starship Pilot in no time!
.BEGIN_SIDEBAR
.H1 Product availability and resources
All of these applications can be found at PilotGear at http://www.pilotgear.com.
Moon Phase can be found at http://home.att.net/~sckienle/palm/home.html.
Moon can be found at http://www.giga.com/~agarza/pilot/moon/.
PalmGlobe can be found at http://www2.hursley.ibm.com/pglobe.
Planetarium can be found at http://www.aho.ch/pilotplanets/.
StarPilot can be found at http://www.star-pilot.com/.
AstroPak (including Sun!, Moon!, and J-Moons!) can be found at http://www3.gamewood.net/mew3/.
AstroInfo can be found at http://www.pilotlibrary.org/pilotsoftware.html.
Tricorder can be found at http://www.mindspring.com/~jetton/pilot.
.END_SIDEBAR
.BIO Keith Johnson is the Associate Director of the Fleischmann Planetarium in Reno, Nevada. He dispenses astronomical wisdom (and a little stellar humor) at http://www.scs.unr.edu/planet/, and can be reached via email at keithj@unr.edu. Keith started writing astronomy programs on stacks of IBM punch cards, graduated to a TI-59 programmable calculator, and is happy to have his Palm computer.
.DISCUSS http://powerboards.zatz.com/cgi-bin/webx?13@@.ee6c7e3
