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Real Sized Planets in Google Sky

September 17th, 2007 Leave a comment Go to comments

Jupiter in Google SkyMoon in Google Sky

Seeing as there are several Google Earth (Sky) KML files all showing live planet positions using Icons, I thought it might be interesting to try something with Image Overlays instead.  One advantage of this method is being able to use detailed photographs, creating the illusion of zoomable objects in the same way as the stars and galaxies in the Google Sky base imagery.

The following file displays the Sun, Moon, planets and Pluto. Positions are automatically updated via a networklink every hour. Note, you will need to zoom in quite a long way to see most of these. Double clicking on the arrow icons will get you there quicker.  

Planets in Google Sky (Google Earth v4.2 Required)

Several other features in the file:

  • Bodies shown at their correct angular size, and polar orientation using scaled and rotated photographs with transparent backgrounds. 
  • The Moon is displayed as one of 50 separate photos, depending on its  current phase.  These are the same images that are in my Lunar timeline.
  • Each overlay is assigned a specific draworder so that during occultations (when one body passes in front of another), they are displayed on top of one another in the right sequence. 

The arrow shaped icons are an attempt to do several things at once:

  • Indicate planet locations without obscuring the overlays.
  • Represent velocity vectors. Pointing in the direction planets are moving.
  • Hopefully, avoid confusion with the Google Sky Layers’ Planet icons. 

I’m currently putting the final touches to a time animated version of this file, which I’ll post tomorrow.      


  • Images are from Wikipedia, originally from NASA. 
  • Ephemerides from JPL Horizons.   The quantities this file is based around are ‘Astronometric declination and right ascension’, ‘Illuminated fraction’ (for the Moon’s phase), ‘Target angular diameter’,  ‘North pole position angle’ and ‘Range’.
  1. September 18th, 2007 at 02:11 | #1

    FANTASTIC! thanks!

  2. September 18th, 2007 at 13:38 | #2

    Great idea as usual James. I’m surprised Google didn’t think of this approach. I’ll probably wait for your animated version tomorrow, and write it up at GEB.

    This should be a nice companion with Michael’s planisphere layer. If you guys happen to use the same time scale, the time animation should match so you can view the horizon and planet position changes at the same time!

  3. September 18th, 2007 at 19:30 | #3

    Yes, the heywhatsthat.com planisphere is very cool. Might be an idea to create several different time duration options for stuff like that. Actually my first thoughts were to tie it into the GE Layers timeline, but I can’t figure out when or how often it updates.

  4. September 18th, 2007 at 19:33 | #4

    This is what I missed in Google Sky. Thanks, James!
    Do you think it is possible to show real time images of the sun, for example from http://sohowww.nascom.nasa.gov/sunspots/ ??

  5. James
    September 19th, 2007 at 08:15 | #5

    Steven – yes.

    Although for high precision you’d probably need to run some code to warp the images first, using something like this: http://code.google.com/p/wcs2kml

  6. csoos
    May 19th, 2008 at 04:54 | #6

    -google sky (I think) misses the ability for the slider to animate planets for 365 days (only for 3 months) to a see a full year’s cycle (and even different YEARS, like… 1625??)

    Q. can your planetary objects vanish after you crash into them with the zoom (thus revealing the stars behind them / while still zooming) ?? might be a nice little feature

  7. Jamie Harley
    December 16th, 2008 at 19:23 | #7

    Hi I really love google sky

  8. zoya
    March 20th, 2009 at 14:24 | #8

    good website but wanted a website that you could download a thiung like google earth but google planets where you can zoom in on all the 9 planets if you could make one o0f those because im doin a science test soon and need some help please that would be great !

  1. September 19th, 2007 at 13:28 | #1
  2. September 21st, 2007 at 02:09 | #2