PIA12276: A Terminator Shot
Target Name: Mercury
Is a satellite of: Sol (our sun)
Mission: MESSENGER
Spacecraft: MESSENGER
Instrument: MDIS - Narrow Angle
Product Size: 1018 x 1024 pixels (width x height)
Produced By: Johns Hopkins University/APL
Full-Res TIFF: PIA12276.tif (1.044 MB)
Full-Res JPEG: PIA12276.jpg (120.6 kB)

Click on the image above to download a moderately sized image in JPEG format (possibly reduced in size from original)

Original Caption Released with Image:

As MESSENGER approached Mercury, the NAC acquired a high-resolution mosaic of the sunlit crescent planet that contained 62 images. To ensure that the entire sunlit portion of Mercury was covered in the mosaic, a few of the images, like the one here, have large areas of blackness. The terminator, the division between the dark night side and light dayside, runs through the middle of this NAC shot. Shadows are elongated in this image, as the craters catch the rays of an evening Sun. At the actual terminator location in this image, only the highest points of crater rims and inner peak rings are seen illuminated by sunlight. Such grazing lighting conditions can provide important information about the heights of geologic features on the surface.

Date Acquired: September 29, 2009
Image Mission Elapsed Time (MET): 162744209
Instrument: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
Resolution: 400 meters/pixel (0.25 miles/pixel)
Scale: This image is about 400 kilometers (250 miles) wide
Spacecraft Altitude: 15,400 kilometers (9,600 miles)

These images are from MESSENGER, a NASA Discovery mission to conduct the first orbital study of the innermost planet, Mercury. For information regarding the use of images, see the MESSENGER image use policy.

Image Credit:
NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington

Image Addition Date:
2009-10-02