We present a brief description of a joint Russian-Korean project abbreviated as EXPLANATION (EXoPLANet And Transient events InvestigatiON). The project is aimed at a massive photometric, speckle-interferometric, spectral, and radio bolometric search for non-stationary events in the Universe, as well as the study of exoplanets. The core of the project consists of several 0.07–2.5-m optical telescopes, 6-m telescope BTA and a six-hundred-meter radio telescope RATAN-600 of the Special Astrophysical Observatory of RAS (Russia), Moscow State University observatory (Russia), Kourovka Observatory (Russia), Crimean Astrophysical Observatory (Crimea), Korea Astronomy and Space Science Institute (Republic of Korea). We discuss the philosophy of the project and its instrumentation, as well as the first obtained results. In this paper we report the results related to the detection of several types of transient events and the study of exoplanets.

The article presents the results of meteor observations with the wide-field monitoring system Mini-MegaTORTORA (MMT-9). There are more than 300 thousand events in the MMT-9 meteor database as of May 2021. The distribution of meteortracks in the sky during the night makes it possible to distinguish active meteor showers, as well as sporadic meteors.We present the results of double-station meteor observations with MMT-9 and FAVOR wide-angle camera, separated by adistance of 3.8 km.

New observations of the RS CVn variable UX Ari were carried out using Mini-MegaTORTORA (MMT-9) wide-field optical monitoring system and robotic wide-angle observation system in Zvenigorod observatory of INASAN. We defined more accurately the cycles of the long-period variability of UX Ari and noticed considerable changes in the shape of the power spectrum. In the long-term region we find three cycles at 5, 13.2 and 30 years. It is possible that some cycles are aliases but the most promising period of 30 years is clearly seen. We suppose that P(cycle) estimations for active stars over 10-50 years intervals should made it possible to build a new family of relations on diagrams P(cycle)/P(rot) versus 1/P(rot).

Here we present the results of our four years long observations of meteors with Mini-MegaTORTORA wide-field monitoring system with sub-second temporal resolution. Over this period, we detected and catalogued more than 175000 faint meteors with magnitudes down to 8-10 mag and angular velocities up to 40 deg/s. Recently, we started double-station observations using Mini-MegaTORTORA together with reconstructed FAVOR camera on 3.8 km baseline. This setup allows to observe tens of faint meteors per night. We present the preliminary results of such observations.

Here we present the summary of operation of a novel 9-channel wide-field optical monitoring system with subsecond temporal resolution, Mini-MegaTORTORA, which systematically surveys the sky since 2014 at Special Astrophysical Observatory on Russian Caucasus. The system is able to observe the sky simultaneously in either wide (∼900 square degrees) or narrow (∼100 square degrees fields of view, either in clear light or with any combination of color (Johnson-Cousins B, V or R) and polarimetric filters installed, with exposure times ranging from 0.1 s to hundreds of seconds. The real-time system data analysis pipeline performs automatic detection of rapid transient events, both near-Earth and extragalactic. The objects routinely detected by Mini-MegaTORTORA also include faint meteors and artificial satellites. The imaging survey performed by Mini-MegaTORTORA also allows to look for a slower variability of various kinds of objects.

In the version of this Letter originally published, the letter í was mistakenly omitted from the surname of the author R. Sánchez-Ramírez. This has now been corrected.

Mini-MegaTORTORA is a nine-channel wide-field camera that continuously monitors the sky looking for rapid optical transients since mid-2014. It is also performing a regular sky survey, and has already acquired nearly half a million images covering every point of Northern Sky hundreds to thousands of times. Photometric analysis of these data may provide a huge amount of information useful for the detection and characterization of different types of variable objects. Here we present a brief description of our activities related to the acquisition, processing, and calibration of these data, as well as examples of uncataloged variable stars of various types detected during the analysis.

Here we report our observations of bright optical flash coincident with Fermi GRB160625B using Mini-MegaTORTORA wide-field monitoring system. The prompt optical emission is correlated with gamma one and lags behind it for about 3 seconds, that suggests that optical and gamma emission are formed in different regions of the burst. The multiwavelength properties of this burst are very similar to ones of Naked-Eye Burst, GRB080319B, we detected earlier with TORTORA camera.

Here we present the project of a Small Aperture Imaging Network Telescope (SAINT), which consists of 500 small telescopes - channels - with 1 sq.deg. fields of view each. The telescope operates either in wide-field monitoring mode, covering 500 square degrees of the sky simultaneously with 0.1 s temporal resolution and detection limit of about 22-23 mag in 1000 s, or in follow-up regime, upon detection of a transient. In the latter case, all the channels immediately repoint towards the transient for its detailed (multicolor, polarimetric, spectroscopic) investigation. In this regime, SAINT is equivalent to 8-m telescope and may be used to solve most of standard astro-physical problems.

Here we report ongoing efforts for an untriggered search of rapid optical transients of various astrophysical and non-astrophysical origins on time scales down to fractions of a second with Mini-MegaTORTORA. Mini-MegaTORTORA is a novel 9-channel wide-field optical monitoring system in operation since 2014 at Special Astrophysical Observatory on Russian Caucasus.

Here we present the project of a Small Aperture Imaging Network Telescope (SAINT), which consists of 500 small telescopes – channels – with 1 sq.deg. fields of view each. The telescope operates either in wide-field monitoring mode, covering 500 square degrees of the sky simultaneously with 0.1 s temporal resolution and detection limit of about 22-23 mag in 1000 s, or in follow-up regime, upon detection of a transient. In the latter case, all the channels immediately repoint towards the transient for its detailed (multicolor, polarimetric, spectroscopic) investigation. In this regime, SAINT is equivalent to 8-m telescope and may be used to solve most of standard astrophysical problems.

Here we report on the results of meteor observations with 9-channel Mini-MegaTORTORA (MMT-9) wide-field optical monitoring system with high temporal resolution. During first 1.5 years of operation more than 90 thousands of meteors have been detected, at a rate of 300-350 per night, with durations from 0.1 to 2.5 seconds and angular velocities up to 38 degrees per second. The faintest detected meteors has the peak brightness about 10 mag, while the majority - from 4 to 8 mag. Some of the meteors have been observed in BVR filters simultaneously. Color variations along the trail for them are determined. All parameters of detected meteors are published online. The database also includes the information on 10 thousands meteors detected by our previous FAVOR camera in 2006-2009 years.