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Prior to 1 September 2008 timings of total and grazing lunar occultations were collected by the International Lunar Occultation Centre (ILOC) in Japan. However from that date ILOC ceased to collect and reduce occultation timings owing to funding constraints. The role was subsequently passed to the International Occultation Timing Association (IOTA) which now provides a global collection facility and requires observations to be submitted through local and/or global co-ordinators.

For total lunar occultations, reports shold be submitted monthly to your local co-ordinator who will carry out a preliminary reduction of timings and quickly advise observers of any problems. After any issues have been resolved co-ordinators batch their data and send it to the IOTA global co-ordinator. Ultimately, reported observations are archived at the VizieR Astronomical Data Centre where they are available for research purposes. Submitting total occultation observations through local co-ordinators also makes it easier for us in Australia and New Zealand to keep track of how many occultation observations are being made in the region.

Grazing lunar occultation reports must be prepared separately from any total occultation reports. Graze reports should *not* be sent your local coordinator, but directly to the IOTA global co-ordinator Dr Mitsuru.Soma. If you are part of a team observing the graze, then individual reports should be sent to your team leader who will gather them together and send them on to Dr Soma. Unlike total occultations, graze reports should be sent to Dr Soma as soon as possible after the event; it is not necessary to wait until the end of the month.

Double star lunar occultation events (including when a double star event is predicted but no double event is observed) should be the subject of an *additional* report and sent directly to Brian Loader.

To record TOTAL, GRAZING AND DOUBLE STAR Observations, use one of the following three methods:

  1. OCCULT Software:

    Both Total and Grazing Occultations can be recorded using the Observation Editor in OCCULT. Remember that graze observations need to be recorded separately from total occultations. Double star occultation reports can also be prepared from the Observation Editor, but must be done so as an *additional* report.


    1. OCCULT is a very large program - 24Mb to 100 Mb depending on which star catalogs you choose to use. However installing the full OCCULT also enables you to accurately predict events for your site, which allows you to plan your observing schedule much more effectively. You can even check your observations yourself by performing a preliminary reduction before sending them on to your co-ordinator.
    2. New observers who have any difficulty in using the Occult Observation editor should contact their local co-ordinator who will provide assistance.
  2. LUNAR REPORT Software:

    LUNAR REPORT is standalone lunar occultation reporting software derived from OCCULT. It is only 175Kb and should be extracted from its zip file to a suitable folder and run from there. A help file is included. (Note: To use this you must have the Microsoft .Net framework installed on your computer.)


    LOW software was written by Eric Limburg and is in common use in several parts of the world, particularly Europe. LOW can also prepare predictions and has other nice features. However like Occult is also big - about 90MB.

Important Notes:

  1. We no longer support the old text file report templates as they require time-consuming manual transcription. Please use one of the above options for all Lunar, Graze and Double Star observations.
  2. With the exception of the additional report generated for double star events, it is essential that observations are otherwise NOT REPORTED TWICE.
  3. New observers who might be having difficulty using the OCCULT Observation Editor should contact their local co-ordinator who can provide assistance. Brian Loader has also kindly offered to assist new observers in setting up a pre-filled template form containing their positional data and telescope information. Then only event details need be added.

Where Do I send my Observations?


Unlike total and grazing occultations, when you monitor a possible asteroidal occultation it is important to submit a report WHETHER YOU SEE AN OCCULTATION OR NOT. The reason for this is that even if you did not see an event, your negative observation might still be crucial in determining the diameter of the asteroid. For example, if you were just outside the area in which an occultation was observed, your observation may help define the southern or northern limit of the occultation band, thereby providing a constraint on the deduced size of the asteroid. There are many occasions where such negative observations have proven to be of crucial importance to obtaining a meaningful result.

You can report your PLANETARY OCCULTATION observations using one of the following two methods:

  1. OCCULTWATCHER Software:

    OCCULTWATCHER is a very comprehensive program which allows observers to co-ordinate their observations over a wide geographical area in real time. It is regarded as essential software by all regular observers. OCCULTWATCHER features a number of optional Add-Ins, one of which will assist you in preparing an Excel spreadsheet report form. However to use this feature you must first download and install the "IOTA Reporting" Add-In from this page. Once the time of an event has passed you can right-click on the event and choose "Report Observation". The Add-In contains some basic error-checking to assist you in filling out the report correctly.

  2. Excel Minor Planet Occultation Report Form:

    If you are unable to report your observation using OCCULTWATCHER we prefer that your observations are reported using this form. If you do not have Microsoft Excel or OCCULTWATCHER you can instead use our Text-only Minor Planet Occultation Report Form. The co-ordinators receive a large number of reports so it is of considerable help to them if you can carefully follow the instructions contained in each form.

    NOTE: There is a strict naming convention for planetary occultation reports which is fully explained in our Planetary Occultation Report Naming Standards Word document. (This document should be able to be opened using Microsft Word, Open Office, or a range of other word-processing programs. If you have difficulty please consult the co-ordinator below.)

Please forward reports to the Planetary Occultation co-ordinator for Australia and New Zealand John Talbot, with a copy to Director OCCSEC . Reports (whether positive or negative) should be submitted as soon as possible after each event, but certainly at least as frequently as once a month.

Important Notes:

  1. Please do not delete any raw data (such as video recordings) before your co-ordinator has had a chance to check and reduce your results, as resolving any issues may require access to the raw data.
  2. The Excel and Text-based forms are intended for use only by observers in Australia, New Zealand and the Pacific Islands. If you are observing from other regions you should obtain the correct forms to use from your local co-ordinator via the websites below:

Europe Japan North America Latin America


English translation


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