FAVOR is the project for wide field investigation of the sky on short time scales. Main instrument of the project is the optical camera with unique combination of FOV dimensions and limiting magnitude for such a short exposure: it can detect 11.5^m stars for 0.13 seconds in the 15x20 degree field of view. FAVOR development is led by collaboration of IKI, Kosmoten and SAO.

Main purposes

Primary goal is to detect flashes and, more general, variability of any objects in the field. The most important for us are optical flashes related to the gamma-ray bursts (GRBs).

However there is other possibility to investigate near-Earth space. Using data from Camera we can refine orbital elements of satellites and obtain useful infomation concerning to meteors.

BASIS

GRBs initially were being investigated only in gamma range using space born telescopes. Recently optical observations became possible too. But till now they are crucially limited: all optical observations are carried out after the burst in posterior moments of time. And only in one case a prompt optical emmision was successfully registered by fast response telescope - GRB990123. ROTSE was alerted via network, started observation 22 s after GRB trigger and recorded optical emission with a maximum brightness about 9 mag (Akerlof et al. 1999). In several other cases rapid telescopes located bursts positions essentially later to detect prompt emission. So in such a classical approach (alert is generated by a gamma-ray telescope and spreaded via the network) time delay between a burst and a start of optical observations could not be less then typical duration of the burst (10 s). Therefore alert-based system could not effectively record prompt emission.

We propose another way for catching of this prompt emission. All above problems can be solved by continuous wide angle sky monitoring and analisis of any variability in the field. It is easily to show that probability of having a GRB in the field increasing with the FOV size faster then with the system sensitivity. Also well known fact is that in optics number of photons from the burst is bigger then in gamma. It provides an opportunity for detailed investigation of central engine of GRB in optics exactly.

That is why we constructed wide field fast optical camera. We hope to obtain prompt optical emission lightcurve with 0.13 s time resolution. In such a field we might have 1-2 GRBs per year and there are some perspectives for essential improvement of this value. Also we plan to spread over GCN relatively accurate (with 20" uncertainty) burst positions just 0.5 s after the burst onset.

Such a combination of FOV and limiting magnitude allows us to observe approximately 50 satellites per hour. That is why sober estimation in 300 satellites per night makes Camera highly desirable/useful instrument for satellite observations. Our accuracy of satellite positions' determination (30 arcsec) is quite enough to cope with most of the tasks that satellite observers should solve. After identification of satellite (using 8300+ satellites database) our software automatically produces its light curve which contains information about rotational dynamics of satellite. Also there is interesting possibility to obtain distance in kilometers to satellites and other near-Earth objects using simultaneous observations on several similar cameras.

On condition that there are no any bright meteor showers we observe from 20 to 30 meteor and/or bolids per hour. It is possible to obtain maximum brightness and even light curve of the every event. It may help to study some chemical properties of this objects. Moreover, we can determine membership of the given meteor to one or another shower and thus calculate zenith hour rate of the shower.

CONCLUSIONS

There are broad and proved possibilities to use Camera for solution of many various problems - from examination of all kinds of optical flashes in the remote space to observations of near-Earth bodies - satellites, meteors etc. At this moment we have already developed software for real-time analisis (or simple logging for subsequent analisis) above-listed (and, of course, unintelligible) events. FAVOR will start continuos work within few months.