In version 4.2, released August 22, 2007, Google Earth added a Sky tool for viewing stars and astronomical images.
Google Sky is produced by Google through a partnership with the Space Telescope Science Institute in Baltimore, the science operations center for the Hubble Space Telescope. Dr. Alberto Conti and his co-developer Dr. Carol Christian of the Space Telescope Science Institute plan to add the public images from 2007, as well as color images of all of the archived data from Hubble’s Advanced Camera for Surveys. Newly released Hubble pictures will be added to the Google Sky program as soon as they are issued. New features such as multi-wavelength data, positions of major satellites and their orbits as well as educational resources will be provided to the Google Earth community and also through Christian and Conti’s website for Sky. Also visible on Sky mode are constellations, stars, galaxies and animations depicting the planets in their orbits. A real-time Google Sky mashup of recent astronomical transients, using the VOEvent protocol, is being provided by the VOEventNet collaboration.
Google Sky will soon face competition from the upcoming product WorldWide Telescope from Microsoft, anticipated soon.
On March 13, 2008 Google made a web-based version of Google Sky available at http://www.google.com/sky
Viewing Sky
In addition to browsing the Earth, Google Earth allows you to view heavenly objects, including stars, constellations, galaxies, planets and the Earth’s moon. To view these objects, click View > Switch to Sky or click . In Sky, the Earth is hidden and the 3D viewer presents a view of the sky.
*Note - When you use Sky, the view is above your current location on Earth. For example, if you go to Paris and open Sky, you will see what is in the sky above Paris at the current time. When you exit Sky, you return to this same location.
in the Layers panel. Currently, these layers folders include:
- Welcome to Sky
- Current Sky Events
- Our Solar System
- Backyard Astronomy
- Featured Observatories
- Education Center
- Historical Sky Maps
- Sky Community
As with other layer folders, you can expand these folders and display or hide layers by checking or unchecking them. You can click on points of interest to fly to and learn more about an object. For example, after checking the Backyard Astronomy layer, you can click a point of interest icon to learn about a particular star.
*Note - Items checked in the Places panel (placemarks, polygons, etc.) appear as you view the sky. If you want to hide these items, just uncheck them in the Places panel.
Sky is Different
In Sky, some Google Earth features are available, while others are disabled. Among other features, the following are available:
- A view of the sky
- Sky layers
- Grid
The following features are not available:
- Google Earth options
- Atmosphere
- All layers except those which pertain to Sky
- Tilting and the tilt slider
- Mouse and controller actions that involve titling (example: pressing the mouse scroll wheel)
- Certain controllers, such as the 3d Connexion devices
- Ability to hide or display the Overview map
- Scale legend
- Options dialog box (to access these settings, return to a view of the Earth)
- Make this my start location
- Start up tips
*Note - You can navigate in Sky exactly as you do in the Earth view, except that you cannot tilt the view.
About Position
Position is depicted in the lower left corner of the 3D viewer. The coordinates are based on the motion of the sky due to the rotation of the Earth. These coordinates appear in the following units:
- RA (Right Ascension) is similar to longitude. It is measured in Hours/Minutes/Seconds (0h00m00.00s) up to 24 hours. Right ascension is tied to the rotation of the Earth - in one hour, this much of the sky rotates past your perspective on Earth.
- Declination corresponds to latitude and is measured in much the same way as RA. It uses -90 degrees to +90 degrees. Declination directly relates to the latitude of your position on the Earth (in other words, the declination for the point right above your head (the zenith) is always equal to your latitude).
As time passes, the RA for the zenith rotates through 24 hours, but the declination remains constant.
Searching Sky
You can search for heavenly objects. To do this, in the Search panel, click one of the following tabs:
- Search the Sky - Use this to search heavenly objects by name (examples: Orion, NCG 2437). Currently, you cannot search for planets.
- Location search - Use this to search by right ascension or declination (see above). Example: 5:34:32.01, 32:00:45.96
After you enter your search terms, click the Search button . Results appear in the Search panel. Double click any result to navigate to that location.
Displaying a Grid in Sky
You can display a grid of latitude and longitude lines over the imagery in the 3D viewer. To turn on the grid do one of the following:
- Select View > Lat/Lon Grid.
- Type Ctrl + L (+ L on the Mac)
The grid appears over the earth imagery as red lines, with each latitude/longitude degree line labeled in an axis across the center of the 3D viewer. You can position a astronomical feature in the 3D viewer and determine its basic spatial coordinates using this grid. As you zoom in, the level of detail of the degree lines increases.
Thank you for Youtube.com, Wikipedia.org & Earth.Google.com