Check Near-Duplicates (CND) API¶

The Check Near-Duplicates API can search for near-duplicates of observations published publicly in the Minor Planet Center database. A near-duplicate is an observation with similar temporal and angular positions to an existing observation.

Endpoint¶

https://data.minorplanetcenter.net/api/cnd

Method: GET

Parameters¶

Parameter	Type	Required	Description	Default
`obs`	List of strings	Yes	80- or 160-character observation records in the MPC1992 format.	NA
`time_separation_s`	Float	No	Temporal threshold (0-60 seconds). Matching observations will have been recorded within this time span with respect to the given observation.	60
`angle_separation_arcsec`	Float	No	Spatial threshold (0-10 arcseconds). Matching observations will have been recorded within this angular radius with respect to the given observation.	5
`omit_separation`	Boolean	No	Exclude calculated separation values from results.	false

Note

160-character "two-line" observations may be concatenated, or the 80-character parts may be in sequential order.

Limits:

Up to 10,000 observations per request.
Searches against publicly published MPC observations only.

Response Format¶

The original request will be included in a request attribute.

An attribute for each search term is included in the results attribute. Note that if the search term is in our database and published, it will always be returned as one of the results. This is called an 'exact' match.

Note

Exact matches may occasionally show non-zero angular separation values. This is due to the numerical difference between the RA/dec values stored in the database and those given in the obs80 string.

The value associated with each search term is a list of dictionaries, giving data about the matching observations. The fields of each match are described below.

Field	Description
`request`	Echo of the original query parameters
`results`	Dictionary mapping each input observation to matching near-duplicates

Each match includes:

Field	Type	Description
`obs80`	String	The 80- or 160- character observation record deemed to be a near-duplicate.
`time_separation_s`	Float	The temporal separation in seconds between the duplicate and the search term.
`angle_separation_arcsec`	Float	The angular separation in arcseconds between the duplicate and the search term.

Examples¶

Python¶

import requests

obs = [
    '     K10CM6D  C2023 05 16.43686615 56 36.807-23 12 43.67         21.55wX~6o8oF51',
    '     K10HB1E  S2010 04 24.76254008 07 33.34 -16 07 52.4                W     C51',
    '     K10HB1E  s2010 04 24.7625401 - 3527.1820 + 5686.2015 - 1729.5218        C51'
]

request = {
    'obs': obs,
    'time_separation_s': 60,
    'angle_separation_arcsec': 5
}

response = requests.get("https://data.minorplanetcenter.net/api/cnd", json=request)
response.raise_for_status()
near_duplicates = response.json()['results']

cURL¶

curl -X GET -H "Accept: application/json" \
  https://data.minorplanetcenter.net/api/cnd \
  -H "Content-type: application/json" \
  -d '{"obs": ["     K10CM6D  C2023 05 16.43686615 56 36.807-23 12 43.67         21.55wX~6o8oF51"]}'