sbpy Field Names

The following table lists field names that are recognized by sbpy when accessing DataClass objects, i.e., Ephem, Orbit, or Phys objects. Each row of the following table represents one property; for each property it lists its description, acceptable field names, provenance (which DataClass class should be used to store this object so that sbpy uses it properly), and its physical dimension (if any).

How do I use this Table?

As an example, imagine you are interested in storing an object’s right ascension into a DataClass object. The field names table tells you that you should name the field either ra or RA, that you should use either a Ephem or Obs object to store the data in, and that the field data should be expressed as angles. Based on this information, we can create a Obs object (presuming that the data were derived from observations):

>>> from sbpy.data import Obs
>>> import astropy.units as u
>>> obs = Obs.from_dict({'ra': [12.345, 12.346, 12.347]*u.deg})
>>> obs['ra']  # doctest: +SKIP
<Quantity [12.345, 12.346, 12.347] deg>

Since RA requires an angle as dimension, we use degrees, but we might as well use radians - sbpy will convert the units where necessary. RA has an alternative field name ('RA'), we can now use that name, too, in order to retrieve the data:

>>> obs['RA']  # doctest: +SKIP
<Quantity [12.345, 12.346, 12.347] deg>

The field name list is always up to date, but it might not be complete. If you think an important alternative name is missing, please suggest it by opening an issue. However, keep in mind that each alternative field name has to be unique and unambiguous. The source list is located as sbpy.data.conf.fieldnames in sbpy/data/__init__.py.

Special Case: Epoch

Please note that epochs generally have to be provided as Time objects. The advantage of using such objects is that they can be readily transformed into a wide range of formats (e.g., ISO, Julian Date, etc.) and time scales (e.g., UTC, TT, TDB, etc.) Hence, sbpy requires that all fields referring to a point in time be provided as Time objects.

Field Name List

Description

Field Names

Provenance

Dimension

Target Identifier

targetname, id, Object

Orbit, Ephem, Obs, Phys

None

Target Designation

desig, designation

Orbit, Ephem, Obs, Phys

None

Target Number

number

Orbit, Ephem, Obs, Phys

None

Target Name

name

Orbit, Ephem, Obs, Phys

None

Epoch

epoch, datetime, Date, date, Time, time

Orbit, Ephem, Obs

Time

Semi-Major Axis

a, sma

Orbit

length

Eccentricity

e, ecc

Orbit

None

Inclination

i, inc, incl

Orbit

angle

Perihelion Distance

q, periheldist

Orbit

length

Aphelion Distance

Q, apheldist

Orbit

length

Longitude of the Ascending Node

Omega, longnode, node

Orbit

angle

Argument of the Periapsis

w, argper

Orbit

angle

Mean Anomaly

M, mean_anom

Orbit

angle

True Anomaly

v, true_anom, true_anomaly

Orbit, Ephem, Obs

angle

Arc Length

arc, arc_length

Orbit

angle

Delta-v

delta_v, delta-v

Orbit, Phys

velocity

Minimum Orbit Intersection Distance wrt Mercury

moid_mercury

Orbit, Phys

length

Minimum Orbit Intersection Distance wrt Earth

moid_earth

Orbit, Phys

length

Minimum Orbit Intersection Distance wrt Venus

moid_venus

Orbit, Phys

length

Minimum Orbit Intersection Distance wrt Mars

moid_mars

Orbit, Phys

length

Minimum Orbit Intersection Distance wrt Jupiter

moid_jupiter

Orbit, Phys

length

Minimum Orbit Intersection Distance wrt Saturn

moid_saturn

Orbit, Phys

length

Minimum Orbit Intersection Distance wrt Uranus

moid_uranus

Orbit, Phys

length

Minimum Orbit Intersection Distance wrt Neptune

moid_neptune

Orbit, Phys

length

Tisserand Parameter wrt Jupiter

Tj, tj

Orbit, Phys

None

MPC Orbit Type

mpc_orb_type

Orbit, Phys

None

Epoch of Perihelion Passage

Tp

Orbit

Time

Orbital Period

P, period

Orbit, Phys

time

Heliocentric Distance

r, rh, r_hel, heldist

Ephem, Obs

length

Heliocentric Radial Velocity

r_rate, rh_rate, rdot, r-dot, rhdot, rh-dot

Ephem, Obs

velocity

Distance to the Observer

delta, Delta, obsdist

Ephem, Obs

length

Observer-Target Radial Velocity

delta_rate, deltadot, delta-dot, deldot, del-dot

Ephem, Obs

velocity

Right Ascension

ra, RA

Ephem, Obs

angle

Declination

dec, DEC, Dec

Ephem, Obs

angle

Right Ascension Rate

ra_rate, RA_rate, ra_rates, RA_rates, dRA, dra

Ephem, Obs

angular velocity

RA*cos(Dec) Rate

RA*cos(Dec)_rate, dra cos(dec), dRA cos(Dec), dra*cos(dec), dRA*cos(Dec)

Ephem, Obs

angular velocity

Declination Rate

dec_rate, DEC_rate, Dec_rate, dec_rates, DEC_rates, Dec_rates, dDec, dDEC, ddec

Ephem, Obs

angular velocity

Proper Motion

mu, Proper motion

Ephem, Obs

angular velocity

Proper Motion Direction

Direction, direction

Ephem, Obs

angle

Solar Phase Angle

alpha, phaseangle, Phase, phase

Ephem, Obs

angle

Solar Elongation Angle

elong, solarelong, solarelongation, elongation, Elongation

Ephem, Obs

angle

V-band Magnitude

V, Vmag

Ephem, Obs

magnitude

Heliocentric Ecliptic Longitude

hlon, EclLon, ecllon, HelEclLon, helecllon

Ephem, Obs

angle

Heliocentric Ecliptic Latitude

hlat, EclLat, ecllat, HelEclLat, helecllat

Ephem, Obs

angle

Horizontal Elevation

el, EL, elevation, alt, altitude, Altitude

Ephem, Obs

angle

Horizontal Azimuth

az, AZ, azimuth

Ephem, Obs

angle

Lunar Elongation

lunar_elong, elong_moon, elongation_moon, lunar_elongation, lunarelong

Ephem, Obs

angle

X State Vector Component

x, X, x_vec

Orbit, Ephem, Obs

length

Y State Vector Component

y, Y, y_vec

Orbit, Ephem, Obs

length

Z State Vector Component

z, Z, z_vec

Orbit, Ephem, Obs

length

X Velocity Vector Component

vx, dx, dx/dt

Orbit, Ephem, Obs

velocity

Y Velocity Vector Component

vy, dy, dy/dt

Orbit, Ephem, Obs

velocity

Z Velocity Vector Component

vz, dz, dz/dt

Orbit, Ephem, Obs

velocity

X heliocentric position vector

x_h, X_h

Orbit, Ephem, Obs

length

Y heliocentric position vector

y_h, Y_h

Orbit, Ephem, Obs

length

Z heliocentric position vector

z_h, Z_h

Orbit, Ephem, Obs

length

Comet Total Absolute Magnitude

m1, M1

Ephem, Obs

magnitude

Comet Nuclear Absolute Magnitude

m2, M2

Ephem, Obs

magnitude

Total Magnitude Scaling Factor

k1, K1

Ephem, Obs

None

Nuclear Magnitude Scaling Factor

k2, K2

Ephem, Obs

None

Phase Coefficient

phase_coeff, Phase_coeff

Ephem, Obs

None

Information on Solar Presence

solar_presence, Solar_presence

Ephem, Obs

None

Information on Moon and target status

status_flag, Status_flag

Ephem, Obs

None

Apparent Right Ascension

RA_app, ra_app

Ephem, Obs

angle

Apparent Declination

DEC_app, dec_app

Ephem, Obs

angle

Azimuth Rate (dAZ*cosE)

az_rate, AZ_rate

Ephem, Obs

angular velocity

Elevation Rate (d(ELV)/dt)

el_rate, EL_rate

Ephem, Obs

angular velocity

Satellite Position Angle

sat_pang, Sat_pang

Ephem, Obs

angle

Local Sidereal Time

siderealtime, Siderealtime

Ephem, Obs

time

Target Optical Airmass

airmass, Airmass

Ephem, Obs

None

V Magnitude Extinction

vmagex, Vmagex

Ephem, Obs

magnitude

Surface Brightness

Surfbright, surfbright

Ephem, Obs

magnitude/angle^2

Fraction of Illumination

frac_illum, Frac_illum

Ephem, Obs

percent

Illumination Defect

defect_illum, Defect_illum

Ephem, Obs

angle

Target-primary angular separation

targ_sep, Targ_sep

Ephem, Obs

angle

Target-primary visibility

targ_vis, Targ_vis

Ephem, Obs

None

Angular width of target

targ_width, Targ_width

Ephem, Obs

angle

Apparent planetodetic longitude

pldetic_long, Pldetic_long

Ephem, Obs

angle

Apparent planetodetic latitude

pldetic_lat, Pldetic_lat

Ephem, Obs

angle

Apparent planetodetic Solar longitude

pltdeticSol_long, PltdeticSol_long

Ephem, Obs

angle

Apparent planetodetic Solar latitude

pltdeticSol_lat, PltdeticSol_lat

Ephem, Obs

angle

Target sub-solar point position angle

subsol_ang, Subsol_ang

Ephem, Obs

angle

Target sub-solar point angle distance

subsol_dist, Subsol_dist

Ephem, Obs

angle

Target North pole position angle

npole_angle, Npole_angle

Ephem, Obs

angle

Target North pole position distance

npole_dist, Npole_dist

Ephem, Obs

angle

Observation centric ecliptic longitude

obs_ecl_long, Obs_ecl_long

Ephem, Obs

angle

Observation centric ecliptic latitude

obs_ecl_lat, Obs_ecl_lat

Ephem, Obs

angle

One-way light time

lighttime, Lighttime

Ephem, Obs

time

Target center velocity wrt Sun

vel_sun, Vel_sun

Ephem, Obs

velocity

Target center velocity wrt Observer

vel_obs, Vel_obs

Ephem, Obs

velocity

Lunar illumination

lun_illum, Lun_illum

Ephem, Obs

percent

Apparent interfering body elongation wrt observer

ib_elong, IB_elong

Ephem, Obs

angle

Interfering body illumination

ib_illum, IB_illum

Ephem, Obs

percent

Observer primary target angle

targ_angle_obs, Targ_angle_obs

Ephem, Obs

angle

Orbital plane angle

orbangle_plane, Orbangle_plane

Ephem, Obs

deg

Constellation ID containing target

constellation, Constellation

Ephem, Obs

None

Target North Pole RA

targ_npole_ra, targ_npole_RA

Ephem, Obs

angle

Target North Pole DEC

targ_npole_dec, targ_npole_DEC

Ephem, Obs

angle

Galactic Longitude

glx_long, Glx_long

Ephem, Obs

angle

Galactic Latitude

glx_lat, Glx_lat

Ephem, Obs

angle

Local apparent solar time

solartime

Ephem, Obs

None

Observer light time from Earth

earthlighttime, Earthlighttime

Ephem, Obs

time

3 sigma positional uncertainty RA

RA_3sigma, ra_3sigma

Ephem, Obs

angle

3 sigma positional uncertainty DEC

DEC_3sigma, dec_3sigma

Ephem, Obs

angle

3 sigma positional uncertainty semi-major axis

sma_3sigma

Ephem, Obs

angle

3 sigma positional uncertainty semi-minor axis

smi_3sigma

Ephem, Obs

angle

3 sigma positional uncertainty position angle

posangle_3sigma

Ephem, Obs

angle

3 sigma positional uncertainty ellipse area

area_3sigma

Ephem, Obs

angular area

3 sigma positional uncertainty root sum square

rss_3sigma

Ephem, Obs

angle

3 sigma range uncertainty

r_3sigma

Ephem, Obs

length

3 sigma range rate uncertainty

r_rate_3sigma

Ephem, Obs

velocity

3 sigma doppler radar uncertainty at S-band

sband_3sigma

Ephem, Obs

frequency

3 sigma doppler radar uncertainty at X-band

xband_3sigma

Ephem, Obs

frequency

3 sigma doppler round-trip delay uncertainty

dopdelay_3sigma

Ephem, Obs

time

Local apparent hour angle

locapp_hourangle

Ephem, Obs

time

True phase angle

true_phaseangle

Ephem, Obs

angle

Phase angle bisector longitude

pab_long

Ephem, Obs

angle

Phase angle bisector latitude

pab_lat

Ephem, Obs

angle

Absolute V-band Magnitude

abs_V, abs_Vmag

Ephem, Obs

magnitude

Satellite X-position

sat_X, sat_x

Ephem, Obs

angle

Satellite Y-position

sat_y, sat_Y

Ephem, Obs

angle

Atmospheric Refraction

atm_refraction, refraction

Ephem, Obs

angle

Infrared Beaming Parameter

eta, Eta

Ephem, Obs

None

Temperature

temp, Temp, temperature, Temperature

Phys, Ephem, Obs

temperature

Effective Diameter

d, D, diam, diameter, Diameter

Phys

length

Effective Radius

R, radius

Phys

length

Geometric Albedo

pv, pV, p_v, p_V, geomalb

Phys

None

Bond Albedo

A, bondalbedo

Phys

None

Emissivity

emissivity, Emissivity

Phys

None

Absolute Magnitude

absmag, H

Phys, Ephem, Orbit

magnitude

Photometric Phase Slope Parameter

G, slope

Phys, Ephem, Orbit

None

Molecule Identifier

mol_tag, mol_name

Phys

None

Transition frequency

t_freq

Phys

frequency

Integrated line intensity at 300 K

lgint300

Phys

intensity

Integrated line intensity at designated Temperature

intl, lgint

Phys

intensity

Partition function at 300 K

partfn300

Phys

None

Partition function at designated temperature

partfn

Phys

None

Upper state degeneracy

dgup

Phys

None

Upper level energy in Joules

eup_j, eup_J

Phys

energy

Lower level energy in Joules

elo_j, elo_J

Phys

energy

Degrees of freedom

degfr, ndf, degfreedom

Phys

None

Einstein Coefficient

au, eincoeff

Phys

1/time

Timescale * r^2

beta, beta_factor

Phys

time * length^2

Total Number

totnum, total_number_nocd

Phys

None

Column Density from Bockelee Morvan et al. 2004

cdensity, col_density

Phys

1/length^2