Minor Planet Center Queries (astroquery.mpc/astroquery.solarsystem.MPC)¶
Getting started¶
This is an Astroquery wrapper for querying services at the IAU Minor Planet Center (MPC). Three services are available:
Minor Planet Center Web Service for comet and asteroid orbits and parameters
Minor Planet Ephemeris Service for comet and asteroid ephemerides
Minor Planet Center Observations Database for obtaining observations of asteroids and comets reported to the MPC
In addition, the module provides access to the MPC’s hosted list of IAU Observatory Codes.
To return the orbit of Ceres and an ephemeris for the next 20 days:
>>> from astroquery.mpc import MPC
>>> from pprint import pprint
>>> result = MPC.query_object('asteroid', name='ceres')
>>> pprint(result)
[{'absolute_magnitude': '3.52',
'aphelion_distance': '2.982',
'arc_length': 80185,
'argument_of_perihelion': '73.73165',
'ascending_node': '80.2869866',
'critical_list_numbered_object': False,
'delta_v': 10.5,
'designation': None,
'earth_moid': 1.58537,
'eccentricity': '0.0775571',
'epoch': '2020-05-31.0',
'epoch_jd': '2459000.5',
'first_observation_date_used': '1801-01-01.0',
'first_opposition_used': '1801',
'inclination': '10.58862',
'jupiter_moid': 2.09127,
'km_neo': False,
'last_observation_date_used': '2020-07-17.0',
'last_opposition_used': '2020',
'mars_moid': 0.93178,
'mean_anomaly': '162.68618',
'mean_daily_motion': '0.21406',
'mercury_moid': 2.1761,
'name': 'Ceres',
'neo': False,
'number': 1,
'observations': 7663,
'oppositions': 119,
'orbit_type': 0,
'orbit_uncertainty': '0',
'p_vector_x': '-0.88282454',
'p_vector_y': '0.3292319',
'p_vector_z': '0.33500327',
'perihelion_date': '2018-05-01.99722',
'perihelion_date_jd': '2458240.49722',
'perihelion_distance': '2.5530055',
'period': '4.6',
'pha': False,
'phase_slope': '0.15',
'q_vector_x': '-0.43337703',
'q_vector_y': '-0.84597284',
'q_vector_z': '-0.3106675',
'residual_rms': '0.51',
'saturn_moid': 6.37764,
'semimajor_axis': '2.7676568',
'tisserand_jupiter': 3.3,
'updated_at': '2021-01-16T13:32:57Z',
'uranus_moid': 15.8216,
'venus_moid': 1.8382}]
>>> eph = MPC.get_ephemeris('ceres')
>>> print(eph)
Date RA ... Uncertainty 3sig Unc. P.A.
deg ... arcsec deg
----------------------- ------------------- ... ---------------- ---------
2021-01-29 03:16:34.000 355.2416666666667 ... -- --
2021-01-30 03:16:34.000 355.56125 ... -- --
2021-01-31 03:16:34.000 355.8812499999999 ... -- --
2021-02-01 03:16:34.000 356.2029166666666 ... -- --
2021-02-02 03:16:34.000 356.5254166666666 ... -- --
2021-02-03 03:16:34.000 356.8491666666667 ... -- --
2021-02-04 03:16:34.000 357.17375 ... -- --
2021-02-05 03:16:34.000 357.4995833333333 ... -- --
2021-02-06 03:16:34.000 357.82625 ... -- --
2021-02-07 03:16:34.000 358.15374999999995 ... -- --
2021-02-08 03:16:34.000 358.48249999999996 ... -- --
2021-02-09 03:16:34.000 358.8120833333333 ... -- --
2021-02-10 03:16:34.000 359.1429166666666 ... -- --
2021-02-11 03:16:34.000 359.47416666666663 ... -- --
2021-02-12 03:16:34.000 359.8066666666666 ... -- --
2021-02-13 03:16:34.000 0.13999999999999999 ... -- --
2021-02-14 03:16:34.000 0.4741666666666666 ... -- --
2021-02-15 03:16:34.000 0.80875 ... -- --
2021-02-16 03:16:34.000 1.1445833333333333 ... -- --
2021-02-17 03:16:34.000 1.4812499999999997 ... -- --
2021-02-18 03:16:34.000 1.8183333333333331 ... -- --
Orbits and parameters¶
Search parameters¶
Individual objects can be found with MPC.query_object, and
MPC.query_objects can return multiple objects. Parameters can be
queried in three manners:
exact match
with a _min suffix, which sets the minimum value for the parameter
with a _max suffix, which sets the maximum value for the parameter
An example of an exact match:
>>> from astroquery.mpc import MPC
>>> result = MPC.query_object('asteroid', name='ceres')
>>> print(result)
[{'absolute_magnitude': '3.52', 'aphelion_distance': '2.982', 'arc_length': 80185,
'argument_of_perihelion': '73.73165', 'ascending_node': '80.2869866', 'critical_list_numbered_object': False, 'delta_v': 10.5,
'designation': None, 'earth_moid': 1.58537, 'eccentricity': '0.0775571', 'epoch': '2020-05-31.0', 'epoch_jd': '2459000.5',
'first_observation_date_used': '1801-01-01.0', 'first_opposition_used': '1801', 'inclination': '10.58862', 'jupiter_moid': 2.09127,
'km_neo': False, 'last_observation_date_used': '2020-07-17.0', 'last_opposition_used': '2020', 'mars_moid': 0.93178,
'mean_anomaly': '162.68618', 'mean_daily_motion': '0.21406', 'mercury_moid': 2.1761, 'name': 'Ceres', 'neo': False,
'number': 1, 'observations': 7663, 'oppositions': 119, 'orbit_type': 0, 'orbit_uncertainty': '0', 'p_vector_x': '-0.88282454',
'p_vector_y': '0.3292319', 'p_vector_z': '0.33500327', 'perihelion_date': '2018-05-01.99722', 'perihelion_date_jd': '2458240.49722',
'perihelion_distance': '2.5530055', 'period': '4.6', 'pha': False, 'phase_slope': '0.15', 'q_vector_x': '-0.43337703',
'q_vector_y': '-0.84597284', 'q_vector_z': '-0.3106675', 'residual_rms': '0.51', 'saturn_moid': 6.37764, 'semimajor_axis': '2.7676568',
'tisserand_jupiter': 3.3, 'updated_at': '2021-01-16T13:32:57Z', 'uranus_moid': 15.8216, 'venus_moid': 1.8382}]
A minimum value:
>>> result = MPC.query_objects('asteroid', inclination_min=170)
which will get all asteroids with an inclination of greater than or equal to 170.
A maximum value:
>>> result = MPC.query_objects('asteroid', inclination_max=1.0)
which will get all asteroids with an inclination of less than or equal to 1.
There is another parameter that can be used, `is_not_null`. This
can be used in the following fashion:
>>> result = MPC.query_objects('asteroid', name="is_not_null")
This will, predictably, find all named objects in the MPC database–but that would take a while!
Sorting and return limits¶
The MPC web service allows a consumer to sort results in order to find a number of objects fitting into the top or bottom of a range of values (or all, if truly desired).
The service also allows a consumer to limit their results to a number of objects, which, when paired with sorting, creates very flexible options.
>>> result = MPC.query_objects('asteroid', order_by_desc="semimajor_axis", limit=10)
This will return the 10 furthest asteroids.
Customizing return fields¶
If a consumer isn’t interested in some return fields, they can use the MPC to limit the fields they’re interested in.
>>> result = MPC.query_object('asteroid', name="ceres", return_fields="name,number")
>>> print(result)
[{'name': 'Ceres', 'number': 1}]
Ephemerides¶
Comet and asteroid ephemerides can be generated using the Minor
Planet Ephemeris Service (MPES).
The MPES supports queries for any comet or asteroid by name,
designation, or packed designation, and any Earth-based location.
Ephemerides are computed starting on a specific date, then for
equally-spaced intervals thereafter. The ephemeris is returned as an
Astropy Table.
Dates and intervals¶
For the ephemeris of asteroid (24) Themis, starting today with the default time step (1 day) and location (geocenter):
>>> from astroquery.mpc import MPC
>>> eph = MPC.get_ephemeris('24')
>>> print(eph)
Date RA Dec Delta r Elongation Phase V Proper motion Direction Uncertainty 3sig Unc. P.A.
deg deg AU AU deg deg mag arcsec / h deg arcsec deg
----------------------- ------------------ ------------------ ----- ----- ---------- ----- ---- ------------- --------- ---------------- ---------
2018-08-16 14:34:53.000 96.46708333333333 23.749722222222225 3.502 2.916 47.5 14.8 12.9 53.08 92.1 -- --
2018-08-17 14:34:53.000 96.85291666666666 23.73638888888889 3.491 2.915 48.1 15.0 12.9 52.91 92.3 -- --
2018-08-18 14:34:53.000 97.23708333333333 23.721944444444443 3.48 2.914 48.7 15.1 12.9 52.74 92.4 -- --
2018-08-19 14:34:53.000 97.62041666666666 23.706666666666667 3.469 2.912 49.3 15.3 12.9 52.56 92.6 -- --
... ... ... ... ... ... ... ... ... ... ... ...
2018-09-02 14:34:53.000 102.82333333333332 23.412499999999998 3.302 2.898 58.1 17.2 12.8 49.7 94.5 -- --
2018-09-03 14:34:53.000 103.18208333333332 23.38611111111111 3.289 2.897 58.7 17.3 12.8 49.46 94.6 -- --
2018-09-04 14:34:53.000 103.53916666666666 23.359166666666667 3.277 2.896 59.4 17.4 12.8 49.21 94.8 -- --
2018-09-05 14:34:53.000 103.89458333333332 23.331666666666667 3.264 2.895 60.0 17.6 12.8 48.96 94.9 -- --
Length = 21 rows
Step sizes are parsed with Astropy’s Quantity. For a time step of 1 hour:
>>> eph = MPC.get_ephemeris('24', step='1h')
>>> print(eph)
Date RA Dec Delta r Elongation Phase V Proper motion Direction Uncertainty 3sig Unc. P.A.
deg deg AU AU deg deg mag arcsec / h deg arcsec deg
----------------------- ----------------- ------------------ ----- ----- ---------- ----- ---- ------------- --------- ---------------- ---------
2018-08-16 14:00:00.000 96.45791666666666 23.75 3.503 2.916 47.5 14.8 12.9 53.09 92.1 -- --
2018-08-16 15:00:00.000 96.47374999999998 23.749444444444446 3.502 2.916 47.5 14.8 12.9 53.08 92.1 -- --
2018-08-16 16:00:00.000 96.49 23.74888888888889 3.502 2.916 47.6 14.8 12.9 53.07 92.1 -- --
2018-08-16 17:00:00.000 96.50624999999998 23.748333333333335 3.501 2.916 47.6 14.9 12.9 53.06 92.1 -- --
... ... ... ... ... ... ... ... ... ... ... ...
2018-08-18 11:00:00.000 97.17999999999998 23.724166666666665 3.482 2.914 48.6 15.1 12.9 52.76 92.4 -- --
2018-08-18 12:00:00.000 97.19583333333333 23.723611111111108 3.481 2.914 48.7 15.1 12.9 52.76 92.4 -- --
2018-08-18 13:00:00.000 97.21208333333333 23.723055555555554 3.481 2.914 48.7 15.1 12.9 52.75 92.4 -- --
2018-08-18 14:00:00.000 97.22791666666666 23.72222222222222 3.48 2.914 48.7 15.1 12.9 52.74 92.4 -- --
Length = 49 rows
Start dates are parsed with Astropy’s Time. For a
weekly ephemeris in 2020:
>>> eph = MPC.get_ephemeris('24', start='2020-01-01', step='7d', number=52)
>>> print(eph)
Date RA Dec Delta r Elongation Phase V Proper motion Direction Uncertainty 3sig Unc. P.A.
deg deg AU AU deg deg mag arcsec / h deg arcsec deg
----------------------- ------------------ ------------------- ----- ----- ---------- ----- ---- ------------- --------- ---------------- ---------
2020-01-01 00:00:00.000 209.16749999999996 -11.63361111111111 3.066 2.856 68.5 18.7 12.7 45.15 110.6 -- --
2020-01-08 00:00:00.000 211.11999999999995 -12.342500000000001 2.98 2.863 73.6 19.2 12.7 42.09 110.2 -- --
2020-01-15 00:00:00.000 212.93749999999997 -12.987222222222222 2.892 2.87 78.9 19.7 12.6 38.7 109.8 -- --
2020-01-22 00:00:00.000 214.60083333333333 -13.564722222222223 2.803 2.877 84.3 19.9 12.6 34.89 109.5 -- --
... ... ... ... ... ... ... ... ... ... ... ...
2020-12-02 00:00:00.000 252.88041666666666 -22.87638888888889 4.224 3.242 4.3 1.3 12.9 54.42 96.9 -- --
2020-12-09 00:00:00.000 255.62041666666664 -23.159166666666664 4.235 3.25 0.5 0.1 12.8 54.31 95.9 -- --
2020-12-16 00:00:00.000 258.36208333333326 -23.395 4.237 3.258 4.9 1.5 13.0 54.07 94.8 -- --
2020-12-23 00:00:00.000 261.09624999999994 -23.583055555555557 4.232 3.265 9.5 2.8 13.1 53.67 93.8 -- --
Length = 52 rows
Observer location¶
Ephemerides may be calculated for Earth-based observers. To calculate Makemake’s ephemeris for the Discovery Channel Telescope (IAU observatory code G37):
>>> eph = MPC.get_ephemeris('Makemake', location='G37')
>>> print(eph)
Date RA Dec Delta r Elongation Phase V Proper motion Direction Azimuth Altitude Sun altitude Moon phase Moon distance Moon altitude Uncertainty 3sig Unc. P.A.
deg deg AU AU deg deg mag arcsec / h deg deg deg deg deg deg arcsec deg
----------------------- ------------------ ------------------ ------ ------ ---------- ----- ---- ------------- --------- ------- -------- ------------ ---------- ------------- ------------- ---------------- ---------
2018-08-16 14:42:27.000 194.66791666666663 24.109722222222224 53.211 52.528 47.2 0.8 17.2 2.62 134.2 53 -9 23 0.33 36 -43 -- --
2018-08-17 14:42:27.000 194.68166666666664 24.09722222222222 53.22 52.528 46.5 0.8 17.2 2.65 133.7 53 -8 23 0.43 46 -54 -- --
2018-08-18 14:42:27.000 194.6958333333333 24.084999999999997 53.229 52.528 45.7 0.8 17.2 2.67 133.1 54 -7 22 0.53 57 -64 -- --
2018-08-19 14:42:27.000 194.70999999999998 24.072777777777777 53.238 52.528 45.0 0.8 17.2 2.69 132.6 55 -7 22 0.63 68 -72 -- --
... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ...
2018-09-02 14:42:27.000 194.93124999999995 23.90583333333333 53.343 52.529 35.9 0.6 17.2 2.93 126.0 63 3 21 0.56 119 58 -- --
2018-09-03 14:42:27.000 194.94874999999996 23.894166666666667 53.349 52.529 35.3 0.6 17.2 2.94 125.6 63 3 20 0.45 106 69 -- --
2018-09-04 14:42:27.000 194.96624999999997 23.88277777777778 53.355 52.529 34.8 0.6 17.2 2.96 125.2 64 4 20 0.33 93 76 -- --
2018-09-05 14:42:27.000 194.98374999999996 23.87138888888889 53.36 52.529 34.2 0.6 17.2 2.97 124.7 64 5 20 0.23 80 72 -- --
Length = 21 rows
Note additional columns are returned for topocentric coordinates.
The observer location may be specified with an IAU observatory code,
an array of longitude (east), latitude, and altitude (parsed with
Quantity), or an
EarthLocation. For example, to compute
Encke’s parallax between Mauna Kea and Botswana:
>>> from astropy.table import Table
>>> from astropy.coordinates import SkyCoord
>>> eph = MPC.get_ephemeris('2P', location='586', start='2003-11-01')
>>> mko = SkyCoord.guess_from_table(eph)
>>> eph = MPC.get_ephemeris('2P', location=('24d', '-22d', '1000m'), start='2003-11-01')
>>> bw = SkyCoord.guess_from_table(eph)
>>> mu = mko.separation(bw)
>>> tab = Table(data=(eph['Date'], mu), names=('Date', 'Parallax'))
>>> print(tab)
Date Parallax
deg
----------------------- ---------------------
2003-11-01 00:00:00.000 0.005050002777840046
2003-11-02 00:00:00.000 0.005439170027971742
2003-11-03 00:00:00.000 0.005202581443927997
2003-11-04 00:00:00.000 0.005302672506812041
... ...
2003-11-18 00:00:00.000 0.006954051057362872
2003-11-19 00:00:00.000 0.007231766703916716
2003-11-20 00:00:00.000 0.007537846117097956
2003-11-21 00:00:00.000 0.0075389478267517745
Length = 21 rows
Working with ephemeris tables¶
Columns in the returned ephemeris tables carry the appropriate units.
Convert the columns to Astropy quantities using the .quantity
attribute. To find comet Hyakutake’s peak proper motion in the sky in
degrees per hour:
>>> eph = MPC.get_ephemeris('C/1996 B2', start='1996-03-01', step='1h', number=30 * 24)
>>> print(eph['Proper motion'].quantity.to('deg/h').max())
0.7756944444444445 deg / h
Sky coordinates are returned as quantities carrying units of degrees.
If a sexagesimal representation is desired, they may be replaced with
strings using the ra_format and dec_format keyword arguments
(see Angle’s to_string for formatting
options):
>>> eph = MPC.get_ephemeris('2P', ra_format={'sep': ':', 'unit': 'hourangle', 'precision': 1}, dec_format={'sep': ':', 'precision': 0})
>>> print(eph)
Date RA Dec Delta r Elongation Phase V Proper motion Direction
hourangle deg AU AU deg deg mag arcsec / h deg
----------------------- ---------- -------- ----- ----- ---------- ----- ---- ------------- ---------
2018-08-16 14:12:18.000 22:52:30.5 -6:18:57 3.076 4.048 161.4 4.6 22.4 36.34 250.9
2018-08-17 14:12:18.000 22:51:35.0 -6:23:43 3.072 4.049 162.6 4.3 22.4 36.67 250.9
2018-08-18 14:12:18.000 22:50:38.9 -6:28:33 3.069 4.05 163.8 4.0 22.3 36.98 250.9
2018-08-19 14:12:18.000 22:49:42.4 -6:33:24 3.066 4.052 165.0 3.7 22.3 37.26 250.9
... ... ... ... ... ... ... ... ... ...
2018-09-02 14:12:18.000 22:36:03.8 -7:43:45 3.057 4.066 177.7 0.6 22.1 38.71 250.9
2018-09-03 14:12:18.000 22:35:04.7 -7:48:48 3.059 4.067 176.5 0.9 22.1 38.62 251.0
2018-09-04 14:12:18.000 22:34:05.8 -7:53:50 3.062 4.068 175.3 1.2 22.1 38.52 251.0
2018-09-05 14:12:18.000 22:33:07.1 -7:58:51 3.064 4.068 174.1 1.5 22.2 38.38 251.0
Length = 21 rows
IAU Observatory Codes and Locations¶
Two methods are available for working with the MPC’s observatory list. To retrieve a list of all observatories:
>>> obs = MPC.get_observatory_codes()
>>> print(obs)
Code Longitude cos sin Name
---- --------- -------- -------- ----------------------------------------
000 0.0 0.62411 0.77873 Greenwich
001 0.1542 0.62992 0.77411 Crowborough
002 0.62 0.622 0.781 Rayleigh
003 3.9 0.725 0.687 Montpellier
004 1.4625 0.7252 0.68627 Toulouse
005 2.231 0.659891 0.748875 Meudon
... ... ... ... ...
Z94 358.8565 0.62725 0.77623 Kempshott
Z95 358.8909 0.76782 0.63883 Astronomia Para Todos Remote Observatory
Z96 359.19369 0.747818 0.661731 Observatorio Cesaraugusto
Z97 359.41647 0.704568 0.70727 OPERA Observatory, Saint Palais
Z98 359.5216 0.77156 0.63405 Observatorio TRZ, Betera
Z99 359.97874 0.595468 0.800687 Clixby Observatory, Cleethorpes
Length = 2099 rows
The results are cached by default. To update the cache, use the
cache=False optional keyword:
>>> obs = MPC.get_observatory_codes(cache=False)
To get the location (longitude, parallax constants, and name) of a single observatory:
>>> print(MPC.get_observatory_location('371'))
(<Angle 133.5965 deg>, 0.82433, 0.56431, 'Tokyo-Okayama')
The parallax constants are rho * cos(phi) and rho * sin(phi) where
rho is the geocentric distance in earth radii, and phi is the
geocentric latitude.
Observations¶
The following code snippet queries all reported observations for asteroid 12893:
>>> obs = MPC.get_observations(12893)
>>> print(obs)
number desig discovery note1 ... DEC mag band observatory
... deg mag
------ --------- --------- ----- ... ------------------- ----- ---- -----------
12893 1998 QS55 -- -- ... -15.78888888888889 0.0 -- 413
12893 1998 QS55 -- -- ... -15.788944444444445 0.0 -- 413
12893 1998 QS55 * 4 ... 5.526472222222222 0.0 -- 809
12893 1998 QS55 -- 4 ... 5.525555555555555 0.0 -- 809
12893 1998 QS55 -- 4 ... 5.524805555555555 0.0 -- 809
12893 1998 QS55 -- 4 ... 5.440555555555556 18.4 -- 809
... ... ... ... ... ... ... ... ...
12893 1998 QS55 -- -- ... 12.63075 18.53 c T05
12893 1998 QS55 -- -- ... 12.63088888888889 18.63 c T05
12893 1998 QS55 -- -- ... 12.631472222222223 18.55 c T05
12893 1998 QS55 -- -- ... 12.669888888888888 18.3 r I41
12893 1998 QS55 -- -- ... 12.71525 18.3 r I41
12893 1998 QS55 -- -- ... 12.716833333333334 18.2 r I41
12893 1998 QS55 -- -- ... 12.717527777777779 18.3 r I41
Length = 1401 rows
The query results of get_observations are parsed
into a QTable by default; it is also possible to
output the original MPC 80-column format strings using the optional
argument get_mpcformat.
The query can only be run for single targets. The target body is
identified either through an asteroid number (as int or str), a
periodic comet number (as str, e.g., '2P'), a provisional asteroid
designation (as str, e.g., '1998 QS55'), or a provisional comet
designation (as str, e.g., 'P/2019 A4'). Note that comet
identifiers have to be accompanied by a comet type identifier (P,
C, X, etc.), e.g., '1P', '354P', 'P/2019 A4',
'C/1932 Y1'. The lack of a comet type identifier may lead to a
misleading target identification or an error being raised. If the
target identifier is not parsed properly, the user can use the keyword
argument id_type to set the target type and identifier type
manually. Asteroid or comet names cannot be queried, as well as
Palomar-Leiden Survey designations, and individual comet fragments. In
case an object name cannot be resolved, a ValueError is raised. If
a query returns no results, a RuntimeError is raised.
Reference/API¶
astroquery.mpc Package¶
MPC Query Tool¶
The International Astronomical Union Minor Planet Center is “the single worldwide location for receipt and distribution of positional measurements of minor planets, comets, and outer irregular natural satellites of the major planets”.
Classes¶
|