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Archive for August, 2011

Maps Of The Moon And Mars For Android

Published in astronomy. 0 Comments

Application Name: Moon Maps

Description: Photo maps of the moon from Lunar Orbiter and Clementine.

Publisher’s website: Moon Map

Cost: Free (ad-supported)

Version/date reviewed: v.1.1.1  /  8-14-11

Phone/OS: Droid X / Android 2.3

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Android Market (mobile app only)
Android Market (browser)

Application Name: Mars Map

Description: Mars map from the Mars Global Digital Image Mosaic.

Publisher’s website: Atlogis Map Shop

Cost: Free (ad-supported)

Version/date reviewed: v.1.0.7  /  8-14-11

Phone/OS: Droid X / Android 2.3

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Android Market (mobile app only)
Android Market (browser)

Something a bit different – geography but not of the Earth, celestial geography of the Moon and Mars. Both apps are similar in appearance and function, not surprising since they’re both from the same company.

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Moon Maps starts off with a whole-moon display; locations of major features and Apollo landing sites are plotted in colored text. As you zoom in, more features are labeled …

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Until you get the highest possible zoom level …

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The horizontal “stripes” are an artifact of the imaging process. These are images from the Lunar Orbiter probes, shot in the 60s on roll film (pre-solid-state imaging), which was processed on the satellite in lunar orbit, scanned in strips, transmitted to Earth, then pieced together to form a continuous image.

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Moon Maps offers an alternative image source from the more-recent Clementine probe, but while the “stripes” are gone, the imagery tends to be darker and of poorer resolution than that from the Lunar Orbiter.

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The app comes with a searchable database of lunar features and Apollo landing sites; select a feature, and it will zoom to the correct location.

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The Mars Map app operates in a similar fashion, though it uses only one image set, the Mars Global Digital Image Mosaic, generated from Viking Orbiter imagery from the 1970s, carefully selected and heavily processed to make it as uniform in lighting as possible across the surface.

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Viking imagery isn’t quite as high in resolution as that from more recent Mars probes, but there’s still lots of interesting features visible …

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… like this great shot of the crater at the top of Olympus Mons (aka Olympus Rupes), one of the largest volcanoes in the solar system, shown here at highest map resolution. As with Moon Maps, there’s also a searchable database to help you locate specific objects, and the locations of probes that landed successfully on Mars (e.g. Viking, Pathfinder, Mars, Spirit and Opportunity).

Other thoughts: Can’t complain too much, since the apps are free, but the ads do take up a fair amount of screen space.

Final thoughts: Great apps for astronomy fans and map nerds alike. I hope the imagery gets updated in the near future with higher-resolution data.




Map Lightning Strikes With ThunderHunter

Published in Google Maps, GPS and weather. 0 Comments

Application Name: ThunderHunter

Description: Uses the lightning flash and succeeding thunderclap to map the location of lightning strikes in real time

Publisher’s website: ThunderHunter

Cost: Free

Version/date reviewed: v.1.2  /  8-10-11

Phone/OS: Droid X / Android 2.3

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Android Market (mobile app only)
Android Market (browser)

It’s “monsoon” season here in Arizona, which means that more days than not, there’s a good chance of thunderstorms. ThunderHunter uses the delay in seeing the lightning flash and hearing the thunder to calculate approximately how far away a lightning strike is. If  you point the phone in the direction of the lightning strike, it uses the phone’s built-in compass and GPS to plot the approximate position of the strike.

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Starting up the app gives you the screen above; the compass in the upper right is live, and shows you the approximate compass direction your phone is pointed. When you see a lightning flash, quickly swivel the phone to point in  the direction you saw the lightning hit, and tap the button with the “eye/lightning” icon …

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Now wait for the thunderclap; when you hear it, tap the button with the “ear/lightning” icon …

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Since light travels almost instantaneously, but sound travels much slower (about 300 meters / second), ThunderHunter uses the difference in time between the flash and the thunder to calculate the distance. The arrow icon at lower left returns you back to the first screen, to wait for another lightning flash. The button at lower right takes you to a Google Maps view …

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… where it uses the calculated distance and the orientation of the phone to plot the location of the lightning strike (cloud/lightning icon);  your current position is plotted as the “green man” icon. The GPS will fire up to get your current position,  then turn off to minimize power use. Use the “arrow” button to go back to the previous screen.

Other issues: Don’t worry about not having the phone pointed in the right direction when the lightning hits. ThunderHunter uses the direction you’re facing when you tap the “ear” icon after hearing the thunder, so as long as you point the phone in the direction you saw the lightning before you hear the thunder, the direction and position will be plotted correctly.

Final thoughts: Clean, simple, fun, does what it’s supposed to. Most comparable apps only calculate distance, ThunderHunter goes the extra step and plots the position. Recommended. I will say that if you can see lightning and hear thunder, you should find a safe place to sit out the storm. Lightning can strike without warning as far as 10 miles away from the storm’s central location.