Don Shedrick

Nov 22, 2002

December DAS Focus

COMPUTERS IN ASTRONOMY by Don Shedrick

Since the introduction of the first handheld Palm Pilot in 1996, PDA (Personal Digital Assistant) products using the Palm OS have grown to become indispensable tools for millions of people worldwide. Today, the Palm OS runs on almost two out of every three PDAs, and a vast assortment of software to run on the Palm OS has been developed by many individuals and companies.

The unique user experience of a Palm Powered device makes for some very useful and powerful applications. This is very true for many astronomical applications that have been developed. A good place to start in looking for astronomical applications for the Palm is the PalmGear web site with a sort for astronomy:

http://palmgear.com/software/answer_category.cfm?categoryIDs=157

I have picked out some of the best to review below. Most are available from PalmGear, or additionally from the developer's web site if shown. Many are freeware, and some have a small registration fee to enable all features, but all can be tried for free to see it you like it.

StarParty is designed to aid observational astronomers at the telescope. It is not a star charting program, but does give very useful information in a very well organized format. It provides an informational database of over 600 deep sky objects and 300 double stars, arranged by various groups and catalogs such as Messier, Caldwell, Herschel, etc., most of which are visible in small to medium sized telescopes. The information may be sorted by object or star catalog number, RA, declination, constellation, magnitude, and others. Object and star observing lists can be limited for your observing location by constellation, magnitude threshold, visible now at selected altitude, and for objects, by type. Observers with Celestron Nexstar telescopes with "GoTo" capabilities can use StarParty to automatically slew to a desired object. The PalmGear web site is:

http://palmgear.com/software/showsoftware.cfm?sid=54905620021122082656&prodID=35445

The web site for the developer of Star Party is:

http://www.pfdsystems.com/starparty.html

Planetarium is an application suitable for the beginning to advanced astronomer. Use it to find or identify objects in the night sky. It calculates the position of the sun, the moon, the planets, up to 9000 stars, hundreds of deep sky objects, comets and asteroids for any time and any geographical position and draws sky maps of any section of the sky. Stars are plotted down to magnitude 6.5. It shows you twilight times, moon phases, and various astronomical information like coordinates, magnitude, distance, rise and set times, etc. of the planets and all the other objects in the sky. Planetarium can also be used with a Telescope. Just tap an object on the star map and read off its Az/Alt or RA/Dec coordinates to set on the compass rings of your telescope. It is even simpler if you have a computerized Telescope that you can connect via the serial port of the Palm. The PalmGear web site is:

http://palmgear.com/software/showsoftware.cfm?sid=54905620021122082656&prodID=1698

The web site for Planetarium is:

http://www.aho.ch/pilotplanets/

PleiadAtlas is an interactive star atlas you can take out into the field. Many other programs show you the night sky as it appears to the unaided eye, but Brian Tung's PleiadAtlas puts its emphasis on showing you enough stars to lead you to your telescopic or binocular target. The star catalogue contains 25,000 stars down to magnitude 7.5 in the default version and about 220,000 stars down to magnitude 9.5 when using the optional field star database. This is plenty enough to do accurate star hopping to find those deep sky objects. Search and display hundreds of deep-sky objects, the Sun, the Moon, and eight major planets from Mercury to Pluto. Zoom out to show a wide-field view of constellations, or zoom in to show dimmer stars. The PalmGear web site is:

http://palmgear.com/software/showsoftware.cfm?sid=54905620021122082656&prodID=14063

The web site for PleiadAtlas is:

http://astro.isi.edu/pleiadatlas/

Moonphase is an application that will graphically display an image of the Moon showing its current phase, or the phase at any selected date. It also shows how many days into the lunar cycle you are, and when the next quarters, full, and new moons will be. The PalmGear web site is:

http://palmgear.com/software/showsoftware.cfm?sid=54905620021122082656&prodID=1489

Earth&Sun is a program for the PalmPilot to show the Sun Illuminated area of the Earth.

It will also display:

The latitude and longitude of an Earth location

The time zone at that location, based on only longitude, not civil boundaries

The current time at that location based on the above time zone

The sunrise, sunset times, and day length at that location

The great circle distance between two locations on the earth

The PalmGear web site is:

http://palmgear.com/software/showsoftware.cfm?sid=54905620021122082656&prodID=4462

The program can be found at:

http://www.40-below.com/palm/earth&sun.html

The RiseSet Program accurately computes the rise, transit and set times for the Sun and the Moon and the length of day. Any date and user location may be specified. The program stores three locations for travelers.

The program also gives:

The altitude and azimuth angles of the Sun/Moon at the current time or at another user specified time

A compass drawing showing the azimuth and altitude angles of the Sun/Moon

The time of the civil, nautical, and astronomical twilight

The date and time of the next Moon phase

The current percent visibility of the Moon

Lunar or solar eclipse information a few days in advance of the event

RiseSet also optionally gives the magnetic compass reading for the Sun/Moon azimuth angle.

The PalmGear web site is:

http://palmgear.com/software/showsoftware.cfm?sid=54905620021122082656&prodID=4463

The program can also be found at developer David Bray's web site:

http://www.40-below.com/palm/

and documentation at :

http://www.40-below.com/palm/riseset.html

Jovian is the all in one observing tool for Jupiter, helping you to easily locate and identify the moons in their orbits, the Great Red Spot's position, and the different zones and belts in Jupiter's atmosphere with their names, all for any given time and date within the Palm's date range. Jovian also lets you animate the moons' orbits around the planet. The PalmGear web site is:

http://palmgear.com/software/showsoftware.cfm?sid=54905620021122082656&prodID=6343

Jovian can also be found at:

http://www.astro-metrics.com/Jovian.html

Foto Timer is an interval timer. You can use it to time long-exposure photographs of celestial objects, or in the darkroom for developing film and images. The PalmGear web site is:

http://palmgear.com/software/showsoftware.cfm?sid=54905620021122082656&prodID=9302

SunCalc is an easy-to-use sunrise and sunset time and position calculator. It calculates sunrise, sunset and twilight times as well as time of the local noon, azimuth of sunset and sunrise, and Sun elevation at noon. Calculations are done in the local time of any selected site on Earth. The program has solar compass to locate sunrise, sunset, and North directions. The PalmGear web site is:

http://palmgear.com/software/showsoftware.cfm?sid=54905620021122082656&prodID=39441

Prolific software developer Akkana Peck from San Francisco, author of Hitchhiker's Guide to the Moon, has developed two Palm OS programs.

Mars2001 displays the current orientation of Mars, and what features should be visible. It uses algorithms from the 2001 RASC Observer's Handbook (which probably won't be totally accurate for future oppositions). You can advance or retard the time by dragging. Drag right or left to rotate the planet ahead or behind by an hour, and tap with the pen to reset to the current time. It can be found at:

http://www.shallowsky.com/software/mars2001.html

SatMoons shows locations of Saturn's moons and the tilt of its rings. You can zoom in and out, and a tap on a moon shows its name and magnitude. It can be found at:

http://shallowsky.com/software/shallow.html