Summary report

Back on the front of the form we find the following items:

• Date: In order to avoid confusion, use the double date if the start was before and the end after 0h UT; e.g. for a watch running between 2215-0015 UT starting on 1993 December 12, the double date would be written as "Date: 12-13 (day), 12 (month), 93 (year)".
• Start: start of the first interval.
• End: end of the last interval.
• Location: Report the geographic longitude and latitude of your observing site as accurately as you know them. E/W means east or west of Greenwich meridian, N/S means north or south of the equator. Several online services (such as Google) give latitude/longitude; note that we use longitude/latitude. Once your first observations have been submitted, the IMO will give your site a code number. If you do not know the code number, for example if you are using a new site, leave this blank.
• Place: Report the name of your observing site. Give the nearest town or village name.
• Observer: Fill in your first and last names. The IMO observer code consists of the first three letters of your last name and the first two letters of your first name. As an example, the code of observer Fritz Schmidt would be SCHFR. If the code exists already for somebody else, or if technical reasons require it, the last letter may differ from this rule.

Observed showers

This table needs to contain:

• The IMO three-letter codes of the showers observed.
• The radiant positions in right ascension and declination valid for the date of the observation (remember to allow for the radiant drift). This information can be found in the Shower Calendar.

Observed numbers of meteors per period per shower: Use one line for each interval.

• Period (UT): Report the start and end of the interval (in UT).
• Field: Fill in the coordinates of the center of your field of view with a accuracy of about 10°. In our example the star delta Cep was reported. From a star atlas we find the corresponding coordinates alpha = 335°, delta = +60°.
• T_eff, F, lm: Fill in the quantities obtained during the interval analysis.

The next set of columns are designed for reporting the observed numbers of shower meteors and sporadics. At the top fill in the appropriate IMO three-letter codes of the showers you observed.

• M: observing method. Fill in "C" for "counting" if you "counted" the meteors without plotting them onto charts or recording their sky coordinates. Use "P" if you were plotting meteors.
• N: number of shower meteors observed during the interval.

If there was more than one interval to your watch, fill in the data from the subsequent intervals in the subsequent lines.

Magnitude distributions:

This table is for reporting the number of shower meteors and sporadics per magnitude class. Again, fill in the IMO three-letter shower code and then on the same line, give the numbers of meteors seen in each magnitude interval. Unless you have seen more than about 100 shower meteors these are totals for the entire observation, not for each interval.

If a meteor was, for instance, of magnitude +4.5, count it as being half in the magnitude class +4 and half in +5. In the end, magnitude classes with half meteors may remain. But in one distribution, such half meteor occurrences should be of an even number.

In the last column, "Tot" (short for "Total"), give the sum of the numbers for the entire line. As this sum must be equal to the sum of the numbers of shower or sporadic meteors for all the intervals reported in the previous table, an easy check can always be made, and any errors rectified at this stage. In our example, 21 Perseids were observed in the first interval, 24 in the second, and 30 in the third. Thus the total for the Perseids must be 75.

Important Notes:

1. If the number of meteors for the most active shower exceeds 100 for the whole observation, you should report a series of separate magnitude distributions, rather than the global one we have discussed so far. To do this, find out how many intervals contained more than about 50 meteors for this shower and then construct an individual magnitude distribution (including both sporadics and all observed showers, not just this most active shower) for each such interval. If one or more intervals remain with less than 50 shower meteors at the end, add these intervals to the immediately previous magnitude distribution, so that you always have 50 or more shower meteors per magnitude distribution. If no single interval contains 50-plus shower meteors, then combine neighboring intervals to achieve this. For example:

   • Interval 1: 34 Geminids
   • Interval 2: 28 Geminids
   • Interval 3: 21 Geminids
   • Interval 4: 37 Geminids
   • Interval 5: 22 Geminids

   Here you should report one separate magnitude distribution for the combined intervals 1 and 2, and another one by combining the intervals 3, 4, and 5.

2. If the limiting magnitude of two adjacent intervals differs by more than 0.5mag you should not incorporate the meteors seen into one magnitude distribution. In this case, it is more useful to report a separate magnitude distribution for each interval. If we use the following data for the Geminid example above, it is clear we cannot combine the intervals quite as easily as just looking at the meteor numbers alone:

   • Interval 1: lm = 6.3mag
   • Interval 2: lm = 6.1mag
   • Interval 3: lm = 5.7mag
   • Interval 4: lm = 5.6mag
   • Interval 5: lm = 6.2mag

   This time, magnitude distributions could reasonably be derived for the combined intervals 1 and 2, 3 and 4, and a third for interval 5.

   When reporting more than one magnitude distribution, add a separate sheet of paper on which you report these extra magnitude distributions. Please be sure to add your name or IMO observer name code and the observation's date, and also indicate to which interval(s) each magnitude distribution belongs on the additional sheet. Remember to note on the form that you have given additional magnitude distributions on another sheet.