Usage

CLI commands:

• mpcorbfile2json: reads an MPCORB file and writes a json file with the same data

• json2mpcorb: reads a json file and writes an MPCORB file with the same data

API interface to read and write MPCORB files from python code examples

Reading:

import mpcorbfile

#read MPCORB.DAT download  from:
#https://www.minorplanetcenter.net/iau/MPCORB/MPCORB.DAT
mpc = mpcorbfile.mpcorb_file('MPCORB.DAT')


#alternatively you can use the mpcorb_extended.json.gz
#download from:
#https://minorplanetcenter.net/Extended_Files/mpcorb_extended.json.gz
mpc = mpcorbfile.mpcorb_file()
bodies=mpc.read_json('mpcorb_extended.json') # mpc.bodies contains the data but also returns it

#mpc.bodies it's a list of dictionaries with the data
print(f'{mpc.bodies[0]})
{'packed_designation': 'a7943',
'H': 24.19,
'G': 0.15,
'Epoch': datetime.datetime(2025, 5, 5, 0, 0),
'M': 184.7538,
'Peri': 195.63684,
'Node': 146.91033,
'i': 11.6102,
'e': 0.0894684,
'n': 1.13494811,
'a': 0.9102319,
'U': '2',
'Ref': 'E2024-JU2',
'Num_obs': 1055,
'Num_opps': 2,
'Arc_length': '2012-2013',
'rms': 0.36,
'Perturbers': 'M-v',
'Perturbers_2': '3Ek',
'Computer': 'Veres',
'Hex_flags': 2049,
'Number': '(367943)',
'Name': 'Duende',
'Last_obs': '20130221',
'epochJD': 2460800.5,
'designation': '367943',
'discover_date': nan,
'orbit_type': 'NEO;Athen'}

Writing:

import mpcorbfile

import datetime
mpc=mpcorbfile.mpcorb_file()
Name='2026 AA1'
epoch = datetime.datetime(2026,1,1)
packed_designation=mpc._pack_designation(Name)
body={'packed_designation':packed_designation,'H': 3.2, 'G': 0.15,
        'Epoch': epoch, 'M': 0.0, 'Peri': 0.0, 'Node': 0.0,
        'i': 0.0, 'e': 0.0, 'n': 0.0, 'a': 0.0,'U': 0.0,
        'Ref': 'MPC 12345', 'Num': 12345, 'Name': 'Test'}
mpc.add(body)
#write MPCORB.DAT format
mpc.write('test.dat')
#or write json
mpc.write_json('test.json')

for more examples see Jupyter notebooks gallery