Abstract: A program was developed for calculating equivalent widths of Fraunhofer spectral lines. Partial analysis of Krat’s material was done.
 

Abstract: In this article meteor shower data are given for observations in 1997 and 1998.
 

Abstract: In this paper a physical model of meteoroids entering the atmosphere, the so called single body theory is discussed. Relative and absolute magnitudes of small, medium and high velocity meteors were calculated. It was shown that meteor has a maximum magnitude when consumes between 2/3 and 3/4 of its initial mass.
 

Abstract: Determination of galactic coordinates of center, and diameter of the biggest radio loop, which we can see in our radio maps, Radio Loop I (the North Polar Spur) is presented. Radio map on 38 MHz was used.
 

Abstract: Balmer jump can be observed in the Sun’s chromosphere spectrum obtained during a total solar eclipse (flash spectrum), as a difference in continuum intensities less and greater than 364.6nm. In order to record Balmer jump during the 1999 total solar eclipse, two ways of constructing and mounting a spectrograph, namely alt-azimuth and equatorial mountings, were considered. The spectrograph consists of a Rowland – type grating, a slit and a detector. Choosing a specific detector depends on its characteristics, taking into account that the flash spectrum can be recorded during an extremely short period of time (couple of tens of seconds), which is also discussed in this paper. Among factors that will decide on successfulness of the experiment are the weather, financial and political conditions. Recording Balmer jump during an eclipse can give us characteristics of the Sun’s chromosphere in the described way.
 

Abstract: A way to determine zenithal hourly rate of a meteor stream was presented. One of the ways to observe meteors, also known as counting method, was explained. The Orionid stream was observed using that method from Petnica Science Centre in October 1997. The results obtained from the shown calculations are compatible with the results for the same stream given by International Meteor Organization in past years. With this stream approaching its maximum activity, an increase in meteor brightness was noticed.
 

Abstract: This article deals with the Seeliger’s (gravitational) paradox. It is shown that in order to have finite sum of gravitational forces from all stars, at each point of the Universe, under the assumption of an infinitely large Cosmos with infinite number of stars in it, the average matter density needs to be zero.
 

Abstract: A simple method for recording visual meteor observations in ASCII text file is suggested. The program “Meteor” was written and tested. It uses such a database to calculate zenithal hourly rate.
 

Abstract: Observations of the relative brightness of the sky were done in Horgo{, Yugoslavia and in Kamen Bryag, Bulgaria, during the total solar eclipse on August 11, 1999. Results were compared with observation of the partial solar eclipse on October 24, 1995 in Calcutta, India, and with some simple eclipse models based on the approximations for the limb darkening of the solar disc. The differences were noticed between the relative brightness of the sky during partial and during total solar eclipse. The measured brightness curve of the total eclipse rapidly declines downward immediately before, and it starts to grow up rapidly immediately after the eclipse totality, and the curve of partial eclipse has neither rapid declining nor growing.
 

Abstract: Standardization of digitally written data is considered. ASCII text database is suggested as a standard database for recording meteor observations. Such a standard is applied on International Meteor Organization (IMO) Visual Observing Form – Summary Report.
 

Abstract: The relative brightness of the sky was measured during the total solar eclipse on August 11, 1999, and from that the absolute brightness was derived. The obtained results were compared with some simple eclipse models based on the Schwarzschild – Schuster and Eddington approximations for the limb darkening of the solar disc.
 

Sasa Nedeljkovic, Dragan Milisavljevic: The class for high precision computations, 2000, Primatijada 2000, Lepenski Vir, Yugoslavia;

Abstract: Machine arithmetic differs from real arithmetic primarily in number precision. Because of the fixed word length, arithmetic processors can produce only finite-precision results, whereas real arithmetic can produce results to any degree of precision. In this paper a simple class for high-precision computations is given. Using this class we obtained the first 2000 decimal digits of the number pi.

Dragan Milisavljevic, Sasa Nedeljkovic: Mathematical supplement to the theory of world conspiration (in Serbian: Matematicki prilog teoriji svetske zavere), 2000, Primatijada 2000, Lepenski Vir, Yugoslavia;

Abstract: Mathematical model of a simple economic project is developed. Possible results of such a process are shown. It is shown that well lead project can be finished in real time. Using the model we obtained that well organized group or an individual can own a mid-size state in one millenium. The algorithm was used to compare two different political establishments. Applying this algorithm to the question of spreading an intelligent and technologically developed space race it was determined that such a race could rule the whole Galaxy in astrophysically short time.

Sasa Nedeljkovic, Dragan Milisavljevic: Vertical Propagation of the MHD Waves in a Stratified and Magnetized Plasma (to be published);

Abstract: The magnetohydrodynamic (MHD) waves in an isothermal stratified atmosphere with constant gravity and uniform magnetic field of an arbitrary direction is considered. A new, corrected, theoretical expression for inhomogeneous transversal MHD wave equation is obtained.