SkySafari 3 is a major version upgrade to Southern Stars' (http://www.southernstars.com) iOS astronomy apps. SkySafari is a "planetarium that fits in your pocket."

It puts thousands of stars and planets at your fingertips and lets you find objects in the sky using your iPhone's built-in compass and gyroscope. SkySafari includes hundreds of astronomical images, and contains encyclopedic descriptions of the constellations, stars and planet. And the pro version offers telescope control.

SkySafari comes in three versions: SkySafari 3 (US$2.99, 120K stars, no telescope control); SkySafari 3 Plus($14.99, 2.5M stars, telescope control); and SkySafari 3 Pro ($59.99, 15M stars, telescope control). All three versions require iOS 4 or later. (By the way, Apple has approved the basic version of SkySafari 3 for inclusion in the Apple App Store. The Plus and Pro versions are still in review.)

The new pro version has the largest database of any astronomy app. The "Big Kahuna" weighs in at half a gig, and contains over 15.3 million stars from the Hubble Guide Star catalog, plus 740,000 galaxies down to 18th magnitude, and over 550,000 solar system objects -- including every comet and asteroid ever discovered. Yet it runs just as fast and smoothly as our $3 introductory version.

Here's a detailed list of the new features in all three versions of SkySafari 3:

SkySafari 3 (basic version, replaces SkySafari Lite 2.1):

° There are new horizon panoramas, an improved Sun glow, horizon glow, and sunset effects that give SkySafari a dramatic new appearance.

° A scrolling toolbar gives you easy access to common functions. Swipe the toolbar to access new Compass, Gyro, and Night Vision icons and more.

° Realistically-sized images of the Messier objects are now visible directly in the sky chart.

° Artistic illustrations of all 88 constellations smoothly fade in and out of view as you pan around the sky chart.

° "Momentum" when you swipe the sky chart now gives it a much smoother, "iPhone-like" feel.

° Animated panning to selected objects now provides a much better sense of where they are located in the sky.

° Support for the gyroscope built into the iPhone 4, 4G iPod Touch, and iPad 2 now provides much smoother motion tracking.

° In cooperation with "Sky & Telescope" magazine, SkySafari now gives you the mobile version of S&T's "Sky at a Glance" column, complete with interactive sky charts for each day of the week, and links to more articles on S&T's website.

° "Tonight's Best" is a list of the brightest and most important objects visible in tonight's sky and is customized for your location, date, and time.

°  Night vision mode has numerous improvements, including a Night Vision toolbar button.

° A new "Center" button in the main toolbar makes it easier to center the selected object in the sky chart, and keep it locked there.

° The selected object now stays locked at chart center, instead of flying off screen, when running time flow animation in small fields of view.

° Other interface improvements include an option to always show the chart center coordinates and +/- zoom buttons.
° Comets are now rendered realistically and with tails.

SkySafari 3 Plus (intermediate version, replaces SkySafari 2.1) contains all the improvements of SkySafari 3, plus:

° Orbits of the planets and their moons illustrate their paths through space.

° The Object Info view now shows Ecliptic and Galactic coordinates.

° For Celestron, Orion, and SkyWatcher telescopes, SkySafari now includes a "local Align" function as a replacement for the (apparently broken) Sync command in the NexStar/SynScan hand controller firmware.

° For "Push-To" telescopes with encoders, SkySafari now does a 2-star alignment, eliminating the need to level the telescope mount base.

° For all telescopes, SkySafari now shows a confirmation alert when aligning on a target object, to prevent you from accidentally aligning on the wrong object.

° A new temporary message when connecting or disconnecting SkyWire is less confusing than the alerts used previously.

SkySafari 3 Pro (a new high-end version) includes everything in SkySafari Plus, plus:

° More than 15.3 million stars from the Hubble Guide Star catalog, down to 15th magnitude.

° Over 740,000 deep sky objects, including every galaxy in the Principal Galaxy Catalog down to magnitude 18.

°All 180 known moons in the solar system, including the "irregular" satellites of the outer planets.

° All known comets, asteroids, Kuiper Belt objects, and dwarf planets -- a total of over 550,000 solar system objects.