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Data Set history:
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First version

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Data Set Overview:
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The data from the Rosetta Navigation Camera (NavCam) were calibrated by
Bernhard Geiger; the processing pipeline was implemented by Rafael Andres;
the data set was constructed and submitted by Diego Fraga Agudo on behalf
of the Planetary Science Archives (PSA).

The data were acquired between 2014-10-24 and 2014-11-21. The frequency of

navigation slots was (nominal cadence interrupted by manoeuvres):
  - from 2014-10-24T10:00:00 to 2014-11-03T12:00:00 :
    one 2x2 raster with four images every four hours
  - from 2014-11-03T12:00:00 to 2014-11-15T12:00:00 :
    one 2x2 raster with four images every two hours
  - from 2014-11-15T12:00:00 to 2014-11-21T23:25:00 :
    one 2x2 raster with four images every four hours
  - on 2014-11-12 (lander separation and descent):
    26 additional images (7.5 rasters).
This resulted in 4*229+26=942 navigation images. In addition, 75 context and 4
calibration images were taken, which gives a total of 1021 images.

8 navigation images (two rasters) and 3 context images were lost on 2014-11-20
because the NAVCAM was switched off due to an anomaly. For 54 context images,
rows were lost due to an anomaly in the transfer to the spacecraft memory
(which only occurred for context images).

The comet distance ranged from 10km to 50km.

At the beginning of the period the spacecraft was in circular orbits at about
10km distance from the comet centre. Then, it moved to a 30km orbit inclined
with respect to terminator plane, followed by a close fly-by at 16.5km
distance for Lander delivery. This was followed by an outbound trajectory arc
to 50km distance and re-insertion into bound orbits at 30km.

All images in this data set are radiometrically calibrated data taken using
the imaging mode. The data set contains images using NavCam CAM1
onboard the Rosetta S/C. NavCam instrument contains a second identical camera
called CAM2 but this was used mainly as a backup and the few images taken with
it have not been calibrated and are not included in the Level 3 datasets.

The images can be found in the DATA/CAM1 directory.

For each image, the user can also find the FITS format of the
observation in the EXTRAS/CAM1 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   C  IMG
                      CAM2                      Q  LBL
Where X can be C, Q or be absent. It is present for level 3 data (C for image
and label file, Q for quality map). It is absent for level 2 products.

Examples:
        ROS_CAM1_20160308T154502C.IMG
        ROS_CAM1_20160308T154502Q.IMG
        ROS_CAM1_20160308T154502C.LBL

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

           __C.
              ROS     CAM1    YYYYMMDDThhmmss    PNG
                      CAM2                       LBL

Examples:
        ROS_CAM1_20160308T154502C.PNG
        ROS_CAM1_20160308T154502C.LBL

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

           __CF.
              ROS     CAM1    YYYYMMDDThhmmss       FIT
                      CAM2                          LBL

Where C indicates it is a calibrated image file and F indicates it is in FITS
format.

Examples:
        ROS_CAM1_20160308T154502CF.FIT
        ROS_CAM1_20160308T154502CF.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. Aditionally, the data and its
                documentation was scientifically peer reviewed and all issues
                found were solved.