(meteorobs) Reporting Quadrantid observations

Rainer Arlt rarlt at aip.de
Tue Jan 1 10:33:16 EST 2008


Happy New Year!

The maximum of the Qudrantids is approaching, and some recommenda-
tions for reporting meteor observations may be useful. The electronic 
form at the IMO site, http://www.imo.net/visual/report/electronic, has 
been very useful in producing consistent and well formated reports 
for further processing, and for immediate activity analyses. It has 
not always been easy to be used by everybody though. Perhaps a few
comments help:

- The date is the local double-date. Do not worry about UT dates. 
  The Quadrantid maximum night is '03/04  01  2008' for nearly all
  observers.

- The geographical coordinates are longitude/latitude. Note that
  some internet services work with latitude/longitude.

- Please report short observing periods for the maximum night. Period
  lengths of 15 minutes or less are recommended. The electronic form
  offers 10 periods by default. There is a link to customize the form.
  But I recommend to split your observation into smaller individual
  observations. Input may be spoiled by internet connection or other
  technical problems, and the loss is smaller then.

- The field of view is in degrees both in RA and Dec. If you wish to
  convert RA = 13h into degrees, multiply it by 15, RA = 195 deg.

- Teff is the effective observing time in decimal hours. If an ob-
  serving period lasted from 0219-0230, it is 11 min = 0.183 h.

- F is the field obstruction correction. If clouds disturbed 10%
  of your field (not of the sky) during one period, the fraction
  of field covered is 10% / 100% = 0.1. Then F = 1/(1-0.1) = 1.11.
  Other examples are:  20% -> 1.25,  30% -> 1.43,  40% -> 1.67,  50%
  -> 2.00. Just use these numbers if you feel usure about the maths.

- Lm is the stellar limiting magnitude. It is the magnitude of the
  faintest stars visible to the naked eye; it's observer-specific.
  If you face transparent clouds, do not report both a cloud cover 
  and a reduced limiting magnitude. An Lm reduction is usually suf-
  ficient.

- Magnitude distributions of the Quadrantids should be given for
  a maximum of two combined periods. Please also give the magnitude
  distributions of the other showers (ANT and COM) and the sporadic 
  meteors. One distribution per night is sufficient. You may need to 
  increase the number of magnitude distributions shown in the form by 
  the 'customize' link at the top. Do that before entering any data.

- The ecliptical source ANT (Antihelion source) does not show a
  radiant position at the moment. Do not worry about this.

- If you notice an error in the data you submitted, please send a 
  message to geert at barentsen.be and visual at mo.net and do not submit 
  the observation again.

Geert Barentsen has set up a live activity graph page on the IMO web
site -- http://www.imo.net/live/quadrantids2008/ 
Observations sent in by the electronic form will show up on the live 
page after a few minutes.


Good luck for the Quadrantids!
Rainer

Visual Commission of the IMO


--
Rainer Arlt  --  Astrophysikalisches Institut Potsdam, Germany
www.aip.de/People/rarlt   --   +49-331-7499-354  --  fax: -526




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