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Availability: Archived at NSSDC, accessible from elsewhere


This description was generated automatically using input from the Planetary Data System.

Dataset overview

Framing Camera 2 is one of two identical units flying on Dawn spacecraft. This dataset includes the image files to be used in the calibration of the raw data throughout the mission. These files represent the behaviour of each individual pixel with respect to dark current generation and pixel-to-pixel non-uniformity as a function of the filter. As these are elaborated image products, not obtained from a specific image acquisition, they do not have any ancillary data. The data set contains two types of products. The pixel-to-pixel non-uniformity (flat) images and the dark current generation maps. The flat field images are nominally named FC2_Fx_FLAT_Vnn.IMG, where x is a number between 1 and 8 for the appropriate filter number and they represent perturbations in the illumination of the CCD due to the filter (dust particles, blemishes, etc.), and they are expected to stay fairly constant throughout the mission. Prior to the Vesta encounter, there was the initial in-flight version of the flats for each filter (*V02.IMG) and then a stray-light removed (*V02_SLR.IMG, none for filter 1) version. During Vesta LAMO, 2x2 binned color images were acquired in filters F2, F3, and F4 so binned versions of these flats have been provided as *_V03_BINNED.IMG. After analysis of the Vesta encounter images, a complete set of version 3 flat images was generated for each filter in 64 bit (*_FLAT_V03.IMG) and 32 bit (*_FLAT_32_V03.IMG) formats. Finally, a complete set of normalized color filter (F2-F7) flats with stray-light corrections (*_V02_SLR_NORM) were generated and these have subsequently been used to generate the calibrated data archived for the entire mission. Cruise, Mars Flyby, and Vesta images were all reprocessed prior to archive with the latest version of the flats. Older versions of the flats are included on the archive volume in the ''PREVIOUS_VERSIONS'' subdirectory of the DATA/FLATS directory for completeness. The dark current maps are filter independent and are evolving in time as the sensor is subject to a high-energy particle environment. They are named yyyymmdd_FC2_pppxxxxx_Vnn.IMG, where yyyymmdd is the year, month, and day when the file was created, ppp is the mission phase identifier (e.g. CSH), xxxxxx is an observation identifier (e.g. CYCLE2) where applicable, and nn is the image version number. In general, the highest version available for a given dark image should be used rather than an earlier version. Darks are not available for every activity. If there is no dark provided for a specific activity, then the highest version of the preceding activity dark should be used for calibration. For example, during the Ceres Survey observations, composite darks are only available for the odd numbered cycles. To calibrate Ceres Survey Cycle 2 images, users should select the dark images from Cycle 1 rather than those from Cycle 3. This dataset is the primary record of calibration data as it is produced for the consumption of the bigger scientific community. For more information on the contents and organization of the volume set refer to the AAREADME.TXT file located in the root directory of the data volumes.


Filter number: Given that the imperfections vary from filter to filter, one image is created per filter to account for these imperfection. This map is not expected to vary along the mission, but should it be necessary, a set of images per filter could be generated depending on the time of the mission. Mission phase: It is in the nature of the space missions that radiation damage will evolve for worse during the lifetime of the instruments. This makes necessary to keep track of the radiation damage for the different phases of the mission. However, the time scale for significant variation of the radiation damage effects is in the order of several weeks, so it might not be necessary to produce a new set of reference flat fields with every operational slot of the cameras. Still, whenever one of these files is used in the generation of level 1b data (RDR), the header of the RDR will clearly identfy which one of the images was used for the calibration.


These calibration products have been produced from ground and flight measurements and are intended for use in the calibration pipeline. The data in one calibration file consists of one image frame, with the accompanying header translated into text format in the label. The dimensions and location (pixel coordinates) of each frame are included for the co-location of the calibration and acquired images during the processing. Each frame is formatted into one file (suffix *.IMG), with an attached label.

These data are available on-line from the Planetary Data System (PDS) at:

Alternate Names



  • Planetary Science: Small Bodies

Additional Information



Questions and comments about this data collection can be directed to: Dr. David R. Williams



NameRoleOriginal AffiliationE-mail
Dr. Horst Uwe KellerData ProviderMax-Planck-Institut fur
Dr. Pablo Gutierrez-MarquesGeneral ContactMax-Planck-Institut fur
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