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Catalogue Codes

Observers submitting observations by electronic means (generally e-mail) are required to include observer, measurer and telescope details in every submission.

Observation batches that do not include an observational header will not be recognized as containing observations by the automated processes and will be ignored.

The observational details are to be contained in a series of header lines, beginning with certain keywords specified below and placed before any observations.

  • The first line must begin COD and be followed by a three-character observatory code. If you are reporting observations from a new site, you must specify XXX as the observatory code.
  • The CON keyword is optional for most observers, but must be given for observations made at sites which use program codes. The CON line must be the second line in the header and must contain as its first element the contact name. Additional contact details may then follow.
  • Other lines, which may follow in any order, begin:
    • OBS (followed by the list of observers, no programs)
    • MEA (followed by the list of measurers, no programs)
    • TEL (followed by details of the telescope)
    • NET (followed by the abbreviated name(s) of the catalogue(s) used for the reductions).
    • BND (followed by single character representing the mag band used for magnitude estimates)
    • COM (followed by a textual comment)
    • NUM (followed by a count of the observations in this batch)
  • An additional keyword, ACK, enables the Minor Planet Center automatically acknowledge receipt of your observations. The contents of the ACK text are unimportant (although it should mean something to you!) and will simply be e-mailed back to you to let you know that your e-mail arrived. If it is necessary to communicate designations to you, these will be sent after the batch is processed.
  • By default, the acknowledgement is sent to the e-mail address from which the original message was sent. You can override this default behavior by specifying the AC2 keyword, following it by one or more Internet-style e-mail address, e.g.:
    AC2 This email address is being protected from spambots. You need JavaScript enabled to view it.,This email address is being protected from spambots. You need JavaScript enabled to view it.
    The only restriction of the number of e-mail addresses is that the total length of the line (including the four characters `AC2 ') must be less than or equal to 80 characters. Note that any e-mail address specified with the AC2 keyword is NOT enclosed within square brackets. Any of the e-mail addresses specified can be forwarding addresses at your local site.

Please note the following requirements:

  • All lines must be 80 columns or less in width.
  • The keywords must be in capitals and begin in column 1.
  • The keyword must be followed by a space (ASCII 32).
  • The CON, OBS and MEA lines may extend onto a second or subsequent line, repeating the keyword as necessary.
  • Names of individuals must be specified as initials + surname with spaces separating each part of the name.
  • Initials given must be as given on official documents (e.g., passports, driving licenses, etc.). If your name is `Robert', but you use `Bob' in day-to-day usage, you must still specify your initial as `R.' not `B.'.
  • Names must be specified as mixture of capital and lower-case letters, they must be separated from any following name(s) by a comma and they must not be broken across lines.
  • If more than one initial is given, there must be a space between each of the initials: e.g., `J. R. R. Tolkien'.
  • Hyphenated first names should be abbreviated with the hyphen: e.g., `Jean-Francois Hulot' would be `J.-F. Hulot'.
  • Names that contain non-standard characters (e.g., accents or cedillas) may be specified using standard TeX notation--alternatively, an explanation of any special characters required must be included above the header.
  • When there are multiple versions of the NET catalogue, be sure to include the version identifier. Don't simply specify "USNO" or "GSC": write them as, for example, "USNO-B1.0" or "GSC-2.2".
  • Specification of telescopes must follow the following format: aperture, focal ratio (optional), type of instrument and CCD specifier. Do not specify specific brands of CCD. Do not split telescope details across different TEL lines. Valid examples are 1.0-m f/4.3 reflector + CCD or 0.28-m f/6 Schmidt-Cassegrain + CCD. Further information on telescope details is available.
  • All keywords may be repeated within the body of observations as required. The values associated with repeated keywords apply from the time they are first defined to the time that they are redefined.
  • The contact's e-mail address must be specified within square brackets in the Internet style. Please note that e-mail addresses are given ONLY for the contact person.
  • Only one contact name and address may be given.

Examples of valid headers are as follows:

COD 500
CON S. Holmes, 221B Baker Street, London NW1 4JW, England
CON [This email address is being protected from spambots. You need JavaScript enabled to view it.]
OBS H. Poirot, P. Mason, L. Columbo, C. Chan
MEA J. Watson
TEL 0.50-m f/3.0 reflector + CCD
ACK Batch 001
AC2 This email address is being protected from spambots. You need JavaScript enabled to view it.

COD 500
OBS D. K. Scully, F. W. Mulder, W. Skinner
ACK Batch 042: The truth is in here
The second example shows the minimal header that should be supplied: the contact address, telescope and catalogue details will be taken from a default file, and the list of measurers will be assumed to be the same as the list of observers. You should only use the minimal header form if you are the only observer at that code: don't use the form for sites with multiple programs.

The format of the TEL and NET lines must be as illustrated in recent MPCs (note that specific makes of CCD are not mentioned).

If this is your first submission and your observing site does yet have an observatory code, this must be specified as:

An observatory code will be supplied upon acceptance of the observations for publication.

If your observatory code distinguishes between different programs you may specify the program code after the observatory code, as in the following example:

COD 675 4
Note that program codes are assigned by the MPC, not the observer.

The following examples show incorrect headers (with the reason(s) given in parentheses on the offending line(s)):

COD 500
OBS J.M. Jarre          (Initials in name not separated by a space)

COD 500
OBS Vangelis Papathanassiou              (First name in full, rather than initial)
MEA M. OLDFIELD                          (Name entirely in capitals)
TEL 0.50-m f/4.5 reflector + Graff1 CCD  (Make of CCD must not be mentioned)
NET Guide Star Catalogue                 (Use abbreviation GSC)

OBS J. Garcia           (No COD line)

OBS P. McCartney
COD 500                 (COD line must come first)
If you think you've made a discovery contact This email address is being protected from spambots. You need JavaScript enabled to view it.

Do NOT play with this system.  It is intended for research purposes and all data submitted records your IP address.  Abuse of this submission form will result violations being reported to your ISP and other authorities.

Please use the following form to record observed variable star magnitudes, one submission per observation.  This data will be used as a combined effort in the research of variable stars worldwide.  Please note that any submission without the proper data or format will NOT be recorded in the data file.  Required data elements are indicated with an asterisk.

Observer: *  
Email Address: *  
Hour and minutes of right ascension: * Example: 0058
Declination * Two Digits, Example: 42
Letter, if part of designation, or blank Note: If you are submitting an observation(s) for a star that is not in the validation file enter 9999+99 in the RA & Dec field and use the Remarks field to provide information that will identify the star.
Variable Name. *  See the validation file for the correct wording. If CSV or NSV star, do not use constellation name. If comparison star, give magnitude/comp/direction (i.e., 120 COMP S; 96 COMP NW; VAR? NE)
Date * Must be Formated as MMDDYYYY e.g. 02202002
Time UT * Must be Formated as HHMM e.g. 0102
Magnitude *  
Comment Code:

See Key For
Single Letter Codes
Multi Letter Codes

Blank, or single-letter code (up to four one-letter symbols listed in alphabetical order), and/or multi-letter code (CCDV, PEP, etc.)
For a comment, use one of the code letters listed below, but use the "O" code only if absolutely necessary. If you use "O", you must explain it.
Step magnitude/letter sequence; Comparison stars used: Blank, or step magnitude or letter sequence if magnitude = 0.0; or magnitudes of comparison stars used (omit decimal points, separate magnitudes with ",").
Chart Information: Put type (P for preliminary or S for standard), scale, and date of chart used. If not AAVSO chart, put source (AKV, BAA, TA, RASNZ, etc.)
AAVSO Initials: AAVSO Observer Initials. If you do not know yours, contact Headquarters.
Remarks: Required if you use the "O" for "Other" code in Comment Code. May use for comment about observation (usually not needed). Can be anything about observation.

After Pressing the Submit button, you will be returned to this page for more observations.  When you are finished, simply press the "Back to ASO" button below.

One-letter codes :
          A AAVSO Atlas
          B sky is bright, twilight, light pollution, aurorae
          F unconventional method (out of focus, visual photometer, etc.)
          G non-AAVSO chart with Guide Star Catalog magnitudes
          H haze, mist, fog
          I identification of star is uncertain
          J non-AAVSO chart with HIPPARCOS magnitudes
          K non-AAVSO chart or sequence used
          L low in sky, horizon, trees, obstruction
          M moon present or interferes
          N angle, position angle
          O "other" comment - MUST be explained in EXPLANATION field
          R color comment (star is red, blue, etc.)
          S comparison sequence comment or problem; do not use for non-AAVSO sequence
          T non-AAVSO chart with TYCHO magnitudes
          U clouds
          V faint star, glimpse, near limit
          W weather (includes wind), poor seeing in general
          Y activity in star - outburst, fading, flare, unusual behavior
          Z possibly erroneous, doubtful, observer fatigue
Multi-letter Codes :
CCD Charge-coupled device (unfiltered)
CCDB Charge-coupled device (blue filter)
CCDI Charge-coupled device (infrared filter)
CCDO Charge-coupled device (orange filter)
CCDR Charge-coupled device (red filter)
CCDV Charge-coupled device (visual filter)
COMB Observation is of nuclear and nebulous regions COMBined
NUC Observation is of the NUClear region
PEP Photoelectric photometer (Visual band)
PTG Photographic observation
PV Photovisual observation
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