Format For Astrometric Observations Of Comets And Minor Planets
Minor Planet Center (MPC) Instruction

Astrometric observations of comets, minor planets and natural satellites submitted for publication in the Minor Planet Circulars (MPCs), Minor Planet Electronic Circulars and IAU Circulars are represented by a standard 80-column record. 
The formats are described below. The format beyond column 13 are identical for all three types of object (comets, minor planets and natural satellites). All observations should have a designation--never leave columns 1 to 12 blank. 
SUMMARY OF FORMAT:
Please note that TABs should NOT be used. Columns marked as `blank' should contain spaces (ASCII 32). 
MINOR PLANETS
   Columns     Format   Use
    1 -  5       A5     Minor planet number
    6 - 12       A7     Provisional or temporary designation
   13            A1     Discovery asterisk
Minor planet numbers and provisional designations are official designations assigned by the Minor Planet Center. Temporary designations are designations, preferably no more than six (6) characters long (the absolute maximum is seven (7) characters), assigned by the observer for new or unidentified objects. Temporary designations should consist of alphanumeric characters only: do not include spaces. All observations of the same "new" object should have the same temporary designation. 
COMETS
   Columns     Format   Use
    1 -  4       I4     Periodic comet number
    5            A1     Letter indicating type of orbit
    6 - 12       A7     Provisional or temporary designation
   13            X      Not used, must be blank
Periodic comet numbers and provisional designations are official designations assigned by, respectively, the Minor Planet Center and Central Bureau for Astronomical Telegrams. Temporary designations are designations, up to six (6) characters long, assigned by the observer for new or unidentified objects. In practice, temporary designations on comet observations will be very rare. 
MINOR PLANETS AND COMETS
   Columns     Format   Use
   14            A1     Note 1
   15            A1     Note 2
   16 - 32              Date of observation
   33 - 44              Observed RA (J2000.0)
   45 - 56              Observed Decl. (J2000.0)
   57 - 65       9X     Must be blank
   66 - 71    F5.3,A1   Observed magnitude and band
                           (or nuclear/total flag for comets)
   72 - 77       X      Must be blank
   78 - 80       A3     Observatory code

DETAILED NOTES:
MINOR PLANETS
NUMBER 
Columns 1-5 contain a zero-padded, right-justified number--e.g., an observation of (1) would be given as 00001, an observation of (3202) would be 03202. If there is no number these columns should be blank. 
PROVISIONAL/TEMPORARY DESIGNATION 
Columns 6-12 contain the provisional designation or the temporary designation. The provisional designation is stored in a 7-character packed form. 
Temporary designations are designations assigned by the observer for new or unidentified objects. Such designations should begin in column 6, should not exceed 6 characters in length, and should start with one or more letters. 
It is important that every observation has a designation and that the same designation is used for all observations of the same object. 
DISCOVERY ASTERISK 
Discovery observations for new (or unidentified) objects should contain `*' in column 13. Only one asterisked observation per object is expected. 
COMETS
PERIODIC COMET NUMBER 
Periodic comets that have been observed at more than one return are assigned numbers. Reference should be made to the editorial notices on MPC 23803-23804 and 24421 for more complete details of the circumstances under which numbers are assigned. 
Examples: 
      Comet                  P/ Number    Columns 1-4
                                         should contain
      P/Halley                  1P          0001
      P/Encke                   2P          0002
      P/Biela                   3D          0003
      P/Wild 4                116P          0116
See the complete list of periodic comet numbers. 
ORBIT TYPE 
Column 5 contains `C' for a long-period comet, `P' for a short-period comet, `D' for a `defunct' comet, `X' for an uncertain comet or `A' for a minor planet given a cometary designation. 
PROVISIONAL DESIGNATION 
Columns 6-12 contain a packed version of the provisional designation. The first two digits of the year are packed into a single character in column 6 (I = 18, J = 19, K = 20). Columns 7-8 contain the last two digits of the year. Column 9 contains the half-month letter. Columns 10-11 contain the order within the half-month. Column 12 will be normally be `0', except for split comets, when the fragment designation is stored there as a lower-case letter. 
   Examples:
   1995 A1   = J95A010
   1994 P1-B = J94P01b   refers to fragment B of 1994 P1
   1994 P1   = J94P010   refers to the whole comet 1994 P1
Columns 6-12 may contain a minor-planet provisional designation. In such a situation column 12 will contain a capital letter. 
Examples Of Observations
The following examples show valid comet and minor-planet observations. 
                                    Column
         1         2         3         4         5         6         7         8
123456789 123456789 123456789 123456789 123456789 123456789 123456789 123456789 

    CJ93K010  C1995 01 12.44658 23 20 12.59 -73 00 31.9                      413
    PJ93X010  C1995 01 13.71552 12 08 44.80 +01 55 10.6                      413
    PJ94P01d  C1994 10 14.82517 09 57 25.32 +09 06 28.5          13.3 T      360
    PJ95A010  C1995 01 27.42558 07 45 16.64 +21 40 44.4          20.6 N      691
0007P         C1995 01 07.49677 10 07 09.83 +31 58 36.9                      691
0047P         C1994 12 31.38076 07 40 47.47 +37 40 09.1                      693
0116P         C1995 01 03.21177 02 40 39.14 +18 09 23.5          20.8 T      691

     J91R04W F 1994 04 03.00278 11 28 41.20 +04 14 24.8                      033
     J93P00C cC1994 07 04.57639 17 28 54.97 -38 12 17.1          17.1 V      360
     PLS2645   1994 03 04.63681 11 40 57.89 +06 07 08.6                      399
     T1S3196   1994 05 04.56403 14 26 06.83 -15 41 20.8          16.6        474
     T2S3187  A1973 09 19.21250 00 24 34.59 -01 08 26.0                      675
     T3S2318  C1994 07 12.22157 19 47 43.23 -15 45 37.3                      801
02965         C1994 07 13.97693 17 35 15.33 -00 26 18.9          16.1 R      046

     94ORX0 * C1994 06 08.98877 16 22 02.78 -17 49 13.7          18.5        104
The final example shows how a new object would be reported (94ORX0 is a temporary designation assigned by the observer). Note that accurate observations on two nights are necessary for new discoveries to receive provisional designations.