July is a good month for meteor observers in Poland. Polish observers associated in Comets and Meteors Workshop (CMW) are mostly young people studying at secondary schools or universities. July is the first month of summer holidays. The warm nights, a lot of free time, good weather conditions strongly encourage to observations. Finally about of whole year observations made by CMW members are collected in July and August.
All above facts and rapidly growing interest in meteor observations in Poland during the last few years allowed us to investigate the activity of the stream called -Cygnids or o-Cygnids. Each July in years 1995-1997 many meteor observers watched the sky using visual, telescopic and photographic techniques. In order to obtain most reliable results we had to remove observations made incorrectly or in poor conditions. Using our standard methods (Olech & Wozniak 1996; Olech 1997) we required that:
mean limiting magnitude (LM) in the field of view should be at least 5.0 mag,
cloud coverage correction factor F should be smaller than 1.7,
the radiant of the stream should be above over the horizon (in Polish latitudes during whole July this condition is always satisfied),
the center of the field of view should be at an altitude higher than .
Finally we obtained of effective time of visual observations. During this time a group of 35 CMW members noted 757 possible meteors from -Cygnid stream and 4569 sporadic meteors. More detailed statistics with names of CMW observers is given in Table 1.
Telescopic observations present a very useful tool for meteor investigators. Meteors are very often plotted with a larger accuracy than in case of visual observations. It gives the possibility to study the structure and drift of the radiant. We also obtain information about magnitude distribution for fainter events. The main problem with telescopic observations is that this kind of watching meteors requires good equipment (preferably binoculars with a large field of view mounted on tripod), experienced observers and a lot of patience.
Fortunately July is usually the time in which we organize an Astronomical Camp of CMW, which takes place at the Observational Station of Warsaw University Observatory in Ostrowik. The number of participants is always around 15, so we organize two four persons groups observing visually, one or two persons working with a few cameras pointed at different directions, and three-four persons observing telescopically different fields located from the supposed radiant of -Cygnids. We used mostly , and binoculars and Russian AT-1 refractors (, field of view as large as ). For plotting meteors we use A-type maps of International Meteor Organization (IMO) or Uranometria 2000.0 charts. Of course other observers which do not participate in the camp observe -Cygnids both visually and telescopically at their locations.
Finally 14, our observers obtained of telescopic observations with 234 meteors detected. The number of possible -Cygnids is equal to 41. Table 2 summarizes our telescopic observations.
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