The Explanations page lists the several surveys for which colors are now available for objects, whether listed by the original KIC catalog or not, in the Kepler field. MAST's practice to present colors by running the two filters together followed by an underscores and then the survey acronyms, separated by an underscore. Surveys are defined in the table at the top of the Explanations page. The basic syntax is magnitude1magnitude2_survey1_survey_2. It is also important to distinguish among optical, UV, and IR surveys. For example, "optical surveys" include the KIC, KIS, and "UBV." (We note the technical inconsistency that the "J" given in the KIC is an IR magnitude taken from 2MASS.)
Rules for explicitly listed colors in use in Color/Mag or User-specified input menu lists:
1. The survey acronym is added after giving colors by underscore and italized, generally consisting of a 3 letter acronym, follows iand is separated from the colors by an underscore. Exception: if both surveys are KIC no string follows the color, e.g., gK. ri. Similar for GALEX the only UV survey included here, the survey name is omitted, e.g. FUVNUV.
2. Short wavelength filter is given first in the color name.
3. KIC filters normally need no catalog designation. (Thus, even when SDSS colors will be added later on, 'g' will refer to g_KIC, and g_SDSS will refer to the SDSS g magnitude.
4. Mixing filter magnitudes from two surveys of the same wavelength region (UV, optical, IR) is generally avoided , e.g. there is no gr_KIC_KIS or JH_IRT_KIC. Note that optical surveys" include the KIC, KIS, and "UBV." We ignore the technical inconsistency that the "J" from the KIC, borrowed from 2MASS, is an IR magnitude.
The above rules pertain only to the colors MAST lists in the input menus. Users are otherwise free to download any magnitudes and form arbitrary color combinations. However, users are strongly warned to consider the zeropoint differences between these magnitude systems (as noted in the Explanatioins page) before constructing arbitrary colors.