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Data Set Overview:
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The data from the Rosetta Navigation Camera (NavCam) was extracted by
Bernhard Geiger; the data set was constructed and submitted by Maud
Barthelemy on behalf of the Planetary Science Archives (PSA).

The data have been observed and measured from 31st May 2016 to 28th
June 2016. The frequency of the navigation slots was of one 2x2 raster
every five hours, with interruption by manoeuvres. 524 navigation
images were taken. In addition 8 context images and 12 calibration
ones were taken, which makes a total of 544 images.

There was one navigation image with lost rows.
There was no lost or incomplete context images.

The orbiter was at 17km distance at the beginning. Then it went into a
mapping orbit at 30km. The orbits were two half orbits on the day side
with a minimum phase angle of 45 degrees. At the end, it went into an
28x14km elliptical orbit in the terminator plane.
All images in this data set are raw and uncalibrated data taken using
the imaging mode. The data set contains images resolved using both
NavCams onboard the Rosetta S/C and the DATA directory is organised
to reflect this with two sub directories:
 - CAM1
 - CAM2
CAM2 directory is only present if CAM2 observations are done.
After hibernation exit CAM2 was only switched on to confirm its health
status in a check-out. During the comet escort phase CAM2 will only be
used in the case of a failure of the nominal camera CAM1.

For each image, the user can also find the FITS format of the
observation in the EXTRAS directory.

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Filename Convention:
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In DATA:
The filenaming convention for all data levels is given by:

           __.
              ROS     CAM1    YYYYMMDDThhmmss    IMG
                      CAM2                       LBL

Examples:
        ROS_CAM1_20140223T081016.IMG
        ROS_CAM1_20140223T081016.LBL
        ROS_CAM2_20140223T094017.IMG
        ROS_CAM2_20140223T094017.LBL

In BROWSE:
The filenaming convention for all data levels is given by:

           __.
              ROS     CAM1    YYYYMMDDThhmmss    JPG
                      CAM2                       LBL

Examples:
        ROS_CAM1_20140223T081016.LBL
        ROS_CAM1_20140223T081016.JPG
        ROS_CAM2_20140223T094017F.LBL
        ROS_CAM2_20140223T094017.JPG


In EXTRAS:
The filenaming convention for all data levels is given by:

           __F.
              ROS     CAM1    YYYYMMDDThhmmss       FIT
                      CAM2                          LBL

Examples:
        ROS_CAM1_20140223T081016F.FIT
        ROS_CAM1_20140223T081016F.LBL
        ROS_CAM2_20140223T094017F.FIT
        ROS_CAM2_20140223T094017F.LBL

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Geometry Information - Coordinate System:
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The label files include the following geometric variables:
- SC SUN POSITION VECTOR: The vector from the spacecraft to the Sun
  in equatorial J2000 inertial frame.
- SC TARGET POSITION VECTOR: The vector from the spacecraft to the
  centre of the comet nucleus in equatorial J2000 inertial frame.
- SC TARGET VELOCITY VECTOR: The spacecraft to comet nucleus velocity
  vector in in equatorial J2000 inertial frame.
- TARGET CENTER DISTANCE: The distance between the spacecraft and the
  comet nucleus centre. (Note that also for checkout and stellar
  calibration images the comet nucleus distance is given here.)
- SUB SPACECRAFT LATITUDE and SUB SPACECRAFT LONGITUDE: The latitude
and longitude of the sub-spacecraft point derived from the Flight
Dynamics body-fixed reference frame implicitly specified by the
information provided in the comet attitude file CATT.
- RIGHT ASCENSION and DECLINATION: Right Ascension and Declination of
the camera boresight direction in equatorial J2000 inertial frame.
- CELESTIAL NORTH CLOCK ANGLE: The direction of celestial north at the
  center of the image - measured from the upward direction,
  clockwise to the direction toward celestial north.
- SOLAR ELONGATION: The angle between the line of sight of observation
  and the direction of the Sun.
All geometric values are calculated for the time t = IMAGE TIME
(and not START TIME).

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All data have been validated by
                ESA and found as expected. Any exceptions are noted by
                the DATA_QUALITY field in the label files.