Criteria for accepting or rejecting identifications


Submission rejected without orbit fitting


  • ITF-to-ITF submissions

    Please note that the criteria do not apply to NEOCP objects. The MPC will reject ITF-to-ITF identifications without performing any orbit fitting if any of the following is true:

    • The submission format is incorrect. See the submission format description.
    • The submitted tracklets cover less than 3 distinct nights.
    • The arc length covered by the tracklets is less than 3 days.
    • The number of nights is 3 and the arc length is larger than 40 days.
    • You are trying to submit a two apparition linkage when the second apparition is represented only by a single tracklet regardless of the number of tracklets in the first apparition.

  • ITF-to-DES submissions

    The MPC will reject ITF-to-DES identifications without performing any orbit fitting if any of the following is true:

  • DES-to-DES submissions

    The MPC will reject DES-to-DES identifications without performing any orbit fitting if any of the following is true:


Submissions rejected with orbit fitting


  • ITF-to-ITF submissions

    Please note that the criteria do not apply to NEOCP objects.

    The MPC will reject certain identifications after performing an orbit fit if any of the following is true:

    • If the tracklets cover exactly 3 nights, have an arc length < 40 days and RMS > 0.25" and orbit quality is not sufficient (defined below).
    • If the tracklets cover more than 3 nights, have an arc length < 10 days and RMS > 0.25" and orbit quality is not sufficient (defined below).
    • The orbit fit did not converge.

    Minimum orbit quality definition for 3-nighters: Covariance requirements on the converged orbit: The 1-sigma range for the orbital elements must satisfy the following: semimajor-axis<0.05 AU, perihelion distance<0.05 AU, inclination<0.5 deg, eccentricity<0.05; and the eccentricity of the orbit must be < 0.5.

    MPC accepts multi-opposition ITF-to-ITF submissions when:

    • for 2-opposition orbits, one apparition must have at least 3 nights, the other apparition at least two nights; or
    • for 3-opposition orbits, at least one apparition must have at least 3 nights and another apparition at least two nights; or
    • for 4+ oppositions, at least two distinct nights are present on two apparitions.

    New apparitions are counted by gaps between subsequent nights being longer than 237 days.

  • ITF-to-DES submissions

    The MPC will reject certain identifications after performing an orbit fit if any of the following is true:

    • The orbit fit did not converge.

  • DES-to-DES submissions

    The MPC will reject certain identifications after performing an orbit fit if any of the following is true:

    • The orbit fit did not converge.