Images: Kepler catches first planet-hunting territory sightings

On Thursday, NASA released an initial set of images from the Kepler mission, showing the "star-rich sky" where the telescope will soon begin searching for Earth-like planets.

The so-called "first light" images reveal Kepler's intended patch of sky, a huge field of stars in the Cygnus-Lyra region of the Milky Way galaxy. Among other things, the images show the millions of stars in the full field of view of the Kepler mission, as well as others that zoom in on specific areas of the larger region.

This image shows the Kepler telescope's entire field of view in the Cygnus and Lyra constellations, a full 100 square degrees of sky, or, NASA says, the equivalent of "two side-by-side dips of the Big Dipper."

In this image, there are more than 4.5 million stars, of which more than 100,000 have been selected by NASA as being worth investigation by Kepler. The image is a 60-second exposure, taken on April 8, 2009. It is brighter in the lower right of the image since it's closer to the plane of the Milky Way, and is "jam-packed with stars." As well, it is color-coded: the whiter the star, the brighter it is, while the redder it appears, the fainter it is.

This image also shows the Kepler telescope's full range of view. In the image, NGC 6791, a cluster of stars, as well as TrES-2, a star with a known planet, are highlighted. Over 8 billion years old, the cluster is located 13,000 light-years from Earth.

This is a zoomed image of, among other things, NGC 6791, the cluster of stars that is 8 billion years old and 13,000 light-years from Earth. This type of cluster is known as an "open cluster," since its stars are loosely bound and over the millennia have begun to spread apart from each other.

This image depicts an area that is just 0.2 percent of Kepler's full field of view.

Here, we see, among other things, a zoomed-in image of TrES-2, a star with a "hot Jupiter" type of planet that orbits it every 2.5 days. The image itself is just a small area of Kepler's full field of view, and it is a 60-second exposure taken on April 8, 2009, just one day after the Kepler spacecraft's dust cover was jettisoned.

This is a star chart that depicts the massive patch of sky that the Kepler mission will investigate during its 3.5-year duration.

The focal plane of the Kepler mission, the area where starlight is focused, is seen on the chart as 42 horizontal and verticle rectangles, which represent the 42 charge-coupled devices, or CCDs, of the 95-megapixel camera used by Kepler. "Scientists selected the orientation of the focal plane's field of view to avoid the region's brightest stars," according to NASA, "which are shown as the largest black dots. Some of these bright stars can be seen falling in between the CCD modules, in areas that are not imaged. This was done so that the brightest stars will not saturate large portions of the detectors."