During MESSENGER's flyby of Mercury on January 14, 2008, the Mercury Dual
Imaging System (MDIS) acquired images to create eight different mosaics.
Shown here is an image context sheet with small thumbnail versions of the
MDIS Narrow Angle Camera (NAC) images that were captured as the spacecraft
approached the planet and used to create a high-resolution mosaic of
Mercury. The MDIS instrument is mounted on a pivot, which enables the
camera to point in different directions and see different portions of the
surface. Both small motions of the spacecraft and movement of the pivot
were used to take the images that compose this mosaic sequence. This
mosaic has images in 5 columns by 11 rows, but images of just black space
or of the unlit, dark planet are not shown on this context sheet.
MDIS started this mosaic 55 minutes before MESSENGER's closest pass by
Mercury. The first image of the mosaic was taken in the lower left corner,
and images were subsequently acquired by moving across a row and then up
to start the next row. An image where Mercury's surface fills the image is
about 500 kilometers (310 miles) across. Image names, which are
abbreviated under each image in this context sheet, are derived from the
mission elapsed time (MET) when the image was taken, which is
approximately the time in seconds since launch. The mosaic was planned to
have about 10% overlap between neighboring images, to ensure that a mosaic
could be formed without any gaps. The resulting mosaic is ultimately
created by using the time of each image and corresponding information
about the spacecraft location and viewing geometry at that time to place
all of the images onto a common map of Mercury.
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.
