Database Fields Used by MESSENGERuvvs¶

Two tables are created for each species (Ca, Na, and Mg): xxuvvsdata and xxuvvspointing where xx is the species. Fields in each table:

cauvvsdata, nauvvsdata, mguvvsdata¶

unum: Unique spectrum identifier. This is used to join xxuvvsdata and xxuvvspointing (xxuvvsdata.unum = xxpoainting.pnum)
species: Species in the table. This is uni-valued for each table.
frame: Reference frame for the pointing information. In the database this value is ‘MSO for all spectra, but in can be changed to ‘model’ after being loaded into a MESSENGERdata object.
UTC: UTC start time of the observation.
orbit: Orbit number for the observation.
merc_year: Mercury year since begining of mission. Years are measured from perihelion, so Year 1 is incomplete.
taa: Mercury true anomaly angle in radians.
rmerc: Distance of Mercury from the Sun in AU.
drdt: Mercury’s radial distance from the Sun in km/s.
subslong: Sub-solar longitude in radians.
g: g-value for Mercury relative to the Sun in photons/s.
radiance: Measured radiance in the spectrum in kR.
sigma: Uncertainty in radiance measurement in kR.

pnum: Unique spectrum identifier. This is used to join xxuvvsdata and xxuvvspointing (xxuvvsdata.unum = xxpoainting.pnum)
x, y, z: Spacecraft coordinates in the current reference frame in Mercury radii (Measured relative to Mercury’s center).
xbore, ybore, zbore: Boresight direction ( $\sqrt{xbore^2 + ybore^2 + zbore^2} = 1$ )
obstype: Type of commanded UVVS observation (e.g., UVVSExoScan).
obstype_num: Type number corresponding to obsype (e.g., UVVSExoScan=5).
xtan, ytan, ztan: Location of the point at which the instrument line-of-sight is tangent to Mercury’s surface in Mercury radii (Measured relative to Mercury’s center).
rtan: Distance of the instrument line-of-sight tangent point from Mercury’s center ( $rtan = \sqrt{xtan^2 + ytan^2 + ztan^2}$ )
alttan: Height (altitude) of the line-of-sight tangent point from Mercury’s surface in km ( $alttan = rtan - 1 \mathrm{R_M}$ ).
longtan: Longitude of the tangent point in radians. I’m not sure what coordinate system this is measured in (suface fixed or MSO).
lattan: Latitude of the tangent point in radians.
loctimetan: Local time of the tangent point in hours.
slit: UVVS slit used for the observation (Atmospheric or Surface)