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Pi of the Sky is a system of wide field of view robotic telescopes, which search for short timescale astrophysical phenomena, especially for prompt optical GRB emission. The system was designed for autonomous operation, monitoring a large fraction of the sky to a depth of 12m−13m and with time resolution of the order of 10 seconds. Custom designed CCD cameras are equipped with Canon lenses f = 85 mm, f/d = 1.2 and cover 20° × 20° of the sky each. The final system with 16 cameras on 4 equatorial mounts was completed in 2014 at the INTA El Arenosillo Test Centre in Spain. GRB160625B was an extremely bright GRB with three distinct emission episodes. Cameras of the Pi of the Sky observatory in Spain were not observing the position of the GRB160625B prior to the first emission episode. Observations started only after receiving Fermi/GBM trigger, about 140 seconds prior to the second emission. As the position estimate taken from the Fermi alert and used to position the telescope was not very accurate, the actual position of the burst happened to be in the overlap region of two cameras, resulting in two independent sets of measurements. Light curves from both cameras were reconstructed using the Luiza framework. No object brighter than 12.4m (3σ limit) was observed prior to the second GRB emission. An optical flash was identified on an image starting -5.9s before the time of the Fermi/LAT trigger, brightening to about 8m on the next image and then becoming gradually dimmer, fading below our sensitivity after about 400s. Emission features as measured in different spectral bands indicate that the three emission episodes of GRB160625B were dominated by distinct physics process. Simultaneously observations in gamma-rays and optical wavelengths support the hypothesis that this was the first observed transition from thermal to non-thermal radiation in a single GRB. Main results of the combined analysis are presented.

The presentation focuses on plans of the Pi of the Sky collaboration to participate in the future LSC-Virgo's Electromagnetic (EM) Follow-up campaigns. Pi of the Sky telescope participated in the first "EM Follow-up project", called Looc-Up1-3 2009-2010 organized by LSC-Virgo collaboration. Pi of the Sky brought to the project an instrument with the biggest field of view and with a very high time resolution. Recently Pi of the Sky has signed an Memorandum of Understanding (MOU) with LSC-Virgo for EM Follow-up observations in the Advanced Detector Era (ADE). Plans of the Pi of the Sky telescope for joint observations with advanced LIGO and Virgo detectors will be also outlined.

Pi of the Sky is a system of wide field-of-view robotic telescopes designed for observations of short timescale astrophysical phenomena, especially for prompt optical GRB emission. The apparatus designed for autonomous operation follows the predefined observing strategy and adopts to the actual running conditions, monitoring a large part of the sky with time resolution of the order of 1 - 10 seconds and range 12m-13m. Observation strategy and system design was successfully tested with a prototype detector in Chile and starting 2013 the final Pi of the Sky detector system in operation at the INTA El Arenosillo Test Centre in Spain. For the analysis of the data from a wide field-of-view system a set of dedicated algorithms have been developed, which allowed us to reduce photometry uncertainty for bright stars to the level of 0.015m– 0.02m. Design of the Pi of the Sky telescopes allows also for measurements of near-Earth objects as comets, asteroids, satellites and space debris. Precise determination of the orbit parameters of the geostationary satellites is possible when using a parallax measured with simultaneous observations from Spain and Chile. Dedicated tests have been performed recently to verify system capabilities for observation of objects on lower orbits, moving at higher speeds. First results are discussed in this contribution.

"Pi of the Sky" is a system of wide field of view robotic telescopes, which search for short timescale astrophysical phenomena, especially for prompt optical GRB emission. The system was designed for autonomous operation, monitoring a large fraction of the sky with 12m-13m range and time resolution of the order of 1 - 10 seconds. For now there are two working "Pi of the Sky" observatories: in San Pedro de Atacama (Chile) and near Mazagon in Southern Spain. In this paper we report on the status of the project, as well as recent observation of asteroid 2004BL86, which passed the Earth in late January 2015, DG CVn outburst in 2014, satellites observations and our future plans.

Pi of the Sky is a system of wide field-of-view robotic telescopes designed for observations of short timescale astrophysical phenomena, especially for prompt optical GRB emission. The apparatus was designed for autonomous operation, follows the predefined observing strategy and adopts it to the actual conditions, monitoring a large part of the sky with time resolution of the order of 1 - 10 seconds and range 12m-13m. Observation strategy and system design was successfully tested with a prototype detector working in 2004-2009 at Las Campanas Observatory, Chile, and moved to San Pedro de Atacama Observatory in March 2011. In October 2010 the first unit of the final Pi of the Sky detector system, with 4 CCD cameras, was successfully installed in the INTA El Arenosillo Test Centre in Spain. Simultaneous observations from locations in Chile and Spain allow a systematic search for optical transients of cosmological origin. Accurate analysis of data arising from a wide-field system like Pi of the Sky is a real challenge because of a number of factors that can influence the measurements. We have developed a set of dedicated algorithms which remove poor quality measurements, improve photometric accuracy and allow us to reach uncertainties as low as 0.015– 0.02 mag. Three more units (12 CCD cameras) are being prepared for installation on a new platform in INTA, aiming at a total coverage of about 6400 square degrees. Status and performance of the detectors is presented.

Starting March 2011 the “Pi of the Sky” project has two observatories in use: in northern Chile and in southern Spain. Since then we are able to observe a parallax of objects, which pass close to the Earth. Simultaneous observations from two sites are very important to us, because this allows us to reject false flash observations, due to cosmic radiation, meteors, planes, etc. In this paper we present theoretical limitations of our parallax observations. Moreover, first results are shown.

We present current status of the work on the second edition of the variable star catalogue. We used the data from the period from 2006 to 2007. Our catalogue contains about 1000 variable stars of different types. We determined periods for 34 variable stars, which already exists in the GCVS catalogue. For three of them we determined type of variability, previously unknown.

In October 2010 Pi of the Sky set up a new system, consisting of 4 cameras installed on a new mount, in El Arenosillo, in southern Spain. It was followed by moving the prototype system from Las Campanas Observatory (central Chile) to San Pedro de Atacama (northern Chile) in March 2011. In this paper our new sites, some details about observational conditions and first results in both observatories are described.

The "Pi of the Sky" robotic telescope has been designed for monitoring of a significant fraction of the sky with good time resolution and range. The main goal of the "Pi of the Sky" detector is to look for short timescale optical transients arising from various astrophysical phenomena, mainly for optical counterparts of Gamma Ray Burst (GRB). System design, observations methodology as well as developed algorithms also make this detector a sophisticated instrument looking for novae and supernovae stars and monitoring of blasars and AGNs activity. Final detector consists of two sets of 16 cameras, one camera covering field of view of 20°x20°. It follows that the full system will cover field of view of SWIFT BAT satellite. The final system is under construction now. Required hardware and software tests were performed with a prototype located in Las Campanas Observatory in Chile since June 2004. The most important result by the "Pi of the Sky" prototype so far was an independent detection and observation of the prompt optical emission from the naked-eye GRB080319B.

Gamma-Ray Bursts (GRB) are short impulses of gamma radiation (time duration ranges from 0.1 to 100 s) distributed almost isotropically across the sky. Most probably they arise during explosions or collisions of stars at cosmological distances. In this paper we discuss their origin, properties and current models. The methods of their observations will be also described. At the end short summary of "Pi of the Sky" GRBs observations will be presented, mainly focused on the naked-eye burst GRB080319B.