The Square Kilometre Array telescope at low-frequency (SKA-Low) will be a phased array telescope supporting a wide range of science cases covering the frequency band 50 - 350 MHz, while at the same time asking for high sensitivity and excellent characteristics. These extremely challenging requirements resulted in a design using 512 groups of 256 log periodic dual polarized antennas each (where each group is called “station”), for a total of 131072 antennas. The 512 stations are randomly distributed mostly within a dense area around the centre of the SKA-Low, and then in 3 arms having 16 station clusters each. In preparation for the SKA Phase 1 (SKA1) System Critical Design Review (CDR), prototype stations were deployed at the Murchison Radio-astronomy Observatory (MRO) site (Western Australia) near the Murchison Widefield Array (MWA) radio telescope. The project involved multiple parties in an International collaboration building and testing different prototypes of the SKA1-Low station near the actual site. This resulted in both organisational and logistic challenges typical of a deployment of the actual telescope. The test set-up involved a phased build-up of the complex station of log-periodic antennas, by starting from the deployment of 48 antennas and related station signal processing (called AAVS1.5, where AAVS stands for Aperture Array Verification System), followed by expansion to a full station (AAVS2.0). As reference a station with dipole antennas EDA2 (EDA: Engineering Development Array) was deployed. This test set-up was used for an extensive test and evaluation programme. All test antenna configurations were simulated in detail by electromagnetic (EM) models, and the prediction of the models was further verified by appropriate tests with a drone-based radio frequency source. Astronomical observations on Sun and galaxy transit were performed with calibrated stations of both EDA2, AAVS1.5 and AAVS2.0. All 3 configurations were calibrated. EM modelling and calibration results for the full station AAVS2.0 and EM verification for the AAVS1.5 station are presented. The comparisons between the behaviour of the log-periodic antennas and the dipoles have advanced our understanding the calibration quality and the technological maturity of the future SKA1-Low array.
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.
Presented in this contribution are results gathered by Pi of the Sky during LSC-Virgo O1 science run. Pi of
the Sky took part in LSC-Virgo's Electromagnetic (EM) Follow-up project during first science run of Advanced LIGO detectors between September 2015 and January 2016. LSC-Virgo's EM Follow-up is aimed for searching electromagnetic counterparts to gravitational wave transient candidates. Observing an event both in EM and gravitational wave band might be a important step forward to multi-messenger astronomy. The aim of this paper is to show algorithms used by Pi of the Sky for analysing data taken during the first science run and to present the corresponding results. Concepts of algorithms for the next science run will also be discussed.
Pi of the Sky took part in LSC-Virgo's Electromagnetic (EM) Follow-up project during first science run of Advanced LIGO detectors between September 2015 and January 2016. More than 60 astronomical teams have signed Memorandum-of-Understanding with LSC-Virgo for EM Follow-up project. LSC-Virgo's EM Follow-up is aimed for searching electromagnetic counterparts to gravitational wave transient candidates. Observing an event both in EM and gravitational wave band might be a important step forward to multi-messenger astronomy. The aim of this paper is to show algorithms used by Pi of the Sky for analysing data taken during the science runs.
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, 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 Mazagón 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 five wide field of view robotic telescopes, which search for short timescale astrophysical phenomena, especially for prompt optical GRB emissions. 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. Five fully automatic Pi of the Sky detectors located in Spain (INTA - INTA El Arenosillo Test Centre in Mazagón, near Huelva.) and Chile (SPDA - San Pedro de Atacama Observatory.) have been observing the sky almost every night in search of rare optical phenomena. They also collect a lot of useful observations which include e.g. observations of many kinds of variable stars. To be able to draw proper conclusions from the data received, adequate quality of the data is very important. Unfortunately Pi of the Sky data is subject to systematic errors caused by various factors, such as cloud cover, seen as significant fluctuations in the number of stars observed by the detector, problems with conducting mounting, a strong background of the Moon or the passing of a bright object, e.g. a planet, near the observed star. Some of these adverse effects can be easily detected during the cataloging of individual measurements, but the quality of our data was still not satisfactory for us. In order to improve the quality of our data, we have developed two new procedures based on two different approaches. In this article we will report on these procedures, give some examples, and show how these procedures improve the quality of our data. Later we will compare developed methods, give they advantages and disadvantages and show how we can obtain the best data quality, based only on the best combination of used algorithms results. At the end of this article we will describe how these corrections improve the period detection error, what is the most important result when we want to obtain the physical parameters of the analyzed stars.
Pi of the Sky telescope have taken part in gravitational wave EM follow-up project, runned by LSC-Virgo Collaboration, in its initial run in 2009-2010. Since than gravitational wave detectors are being upgraded and become operation in 2015, when the next science run is planned. The paper focuses on Pi of the Sky preparations to LSC-Virgo EM Follow-up project of gravitational wave transient candidates in 2015+ and on Pi of the Sky results of previous science run 2009-2010.
The Pi of the Sky is a system of two 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. Two fully automatic Pi of the Sky detectors located in Spain (INTA) and Chile (SPDA) almost every night have been observing the sky in search of rare optical phenomena but also collect a lot of usefull observations which include e.g. many kinds of variable stars. To be able to draw proper conclusions from the data received, their adequate quality is very important. Data of the Pi of the Sky are subject to a systematic errors caused by various factors such as e.g. cloud cover seen as significant fluctuations in the number of stars observed by the detector, the problems with conducting mounting, a strong background of the moon or passing of a bright object near the observed star, such as a planet. Some of these adverse effects are already detected during the cataloging of individual measurements, but the quality of our data was still not satisfactory for us. In order to improve quality of our data we developed two new procedures which were based on two different approaches. In this article we will tell some words about these procedures, give an some examples and show how these procedures improve the quality of our data.
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.
The aim of the paper is to show methods used by Pi of the Sky team to search for optical counterparts of GW event candidates during Looc-Up science run1 and methods that we are planning to develop as part of the future Looc-Up. During the future joint GW-EM observations a new Pi of the Sky telescope unit could image more than 1/3 of GW candidate probability maps in less than 10 minutes, taking many pictures of the same observation eld. The system could automatically recognize optical transients and perform follow-ups of interesting events.
Two fully automatic Pi of the Sky detectors with a large field of view, located in Spain (INTA) and
Chile (SPDA) observe the sky in search of rare optical phenomena but also collect observations
which include many kinds of variable stars. To be able to draw proper conclusions from the data
received, their adequate quality is very important. Data of the Pi of the Sky are subject to a
systematic errors caused by various factors such as e.g. cloud cover seen as significant fluctuations
in the number of stars observed by the detector, the problems with conducting mounting, a strong
background of the moon or passing of a bright object near the observed star, such as a planet. Some
of these adverse effects are already detected during the cataloging of individual measurements,
but the quality of our data was still not satisfactory for us. In order to improve quality of our
data we developed two new procedures which were based on two different approaches. In this
article I will tell some words about these procedures, give an some examples and show how these
procedures improve the quality of our data.
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.
In this paper we present analysis of Cepheids using data obtained by the Pi of the Sky detector located
in Las Campanas Observatory in season 2006-2009. We have identified nearly 150 Cepheids classified as
classical, overtone or population II Cepheids. The calculation of Fourier parameters of Cepheid light curves
is described. In order to facilitate Fourier analysis we developed a new program capable to determine a
variability period and calculate Fourier coefficients. Additional program allow for automatic classification
of the variability type of Cepheid basing on neural network. Results of automatic classification of Cepheids
based on a neural network are shown.
At the end of 2010 the new detector of the Pi of the Sky project was installed in the INTA
El Arenosillo Observatory∗ near Huelva, Spain, at the coast of the Atlantic Ocean. The robotic
telescope consisting of 4 CCD cameras on one parallactic mount was installed in the telescope
dome of the BOOTES experiment from IAA. It can monitor about 0.5 steradians of the sky (40x40
degrees) with 10 s time resolution. The device is fully autonomous, designed to work without
human supervision. After successful installation it had to be tested and optimally positioned
before it started taking data. In this paper we describe in details deteremination of the Pointing
Model for the new detector.
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.
After brief introduction to the Pi of the Sky project standard photometry method used in the data reduction
will be described. After data quality cuts uncertainty of the single measurement is of the order of 0.018-0.024
magnitudo for stars 7-10m. With new calibration algorithm taking into account the spectral type of reference
stars stability of the photometry algorithm can be significantly improved. Preliminary results from the BGInd
variable are presented showing than uncertainty of the order of 0.013 can be obtained.
One of the goals of "Pi of the Sky" project is to observe and analyze variable stars. In the second edition of variable
stars we have identified over 70 Cepheids, which we classified further analysis. We identified type of pulsation of these
stars using "Pi of the Sky" data collected since 2006. This paper describes analysis of Cepheids based on Fourier
decomposition, which is powerful method for classification purposes.
We presented preliminary results for our catalogue of the variable stars from the 2006-2007 "Pi of the Sky"
data. Our catalogue contains more than 1 000 variable stars of different type. The most numerous group in our
catalogue are eclipsing variables (515) whereas pulsating variables are less numerous (292). Significant group
consists stars classified simply as "variable" (180). For these stars we can not be able to determine more detailed
type of the variability. Our classification was based on the shape of the light curve, as in the GCVS catalogue.
However, some stars from the GCVS catalogue were classified differently in our catalogue.
We present a method of determination of space debris detection possibility by the "Pi of the Sky" telescopes,
based on observations made during normal service. Main feature of objects orbiting Earth is its movement on
celestial sphere, comparing to the stars. This movement diminishes measured brightnesses of these objects, and
in consequence influences possibilities of satellite detection. The altitude of orbit decreases, the satellite should
be brighter, but at the same time possibility of detection diminishes because of higher angular velocity in the
sky. As preliminary results we show an estimations of both of these effects.
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.
Real-time analysis of data from optical telescopes becomes very important topic in the modern astronomy. Particularly
interesting and important is fast automatic identification of short optical transients. Many violent and interesting
processes occur on very short timescales. Such kind of processes may be related to gamma-ray bursts, but there are also
other interesting processes in the short time regime. One of the biggest problems with their investigation is fast
detection and distribution, which would allow deeper studies in the most interesting phase of the event. Thus
development of real-time pipelines for identification of optical transients is a very hot topic. Another issue which
becomes important is that data streams produced by modern astronomical experiments becomes larger and larger,
which requires real-time analysis and pre-selection of only most interesting data. We present implementation of such a
pipeline dedicated to identification of optical transients in the "Pi of the Sky" experiment.
The "Pi of the Sky" system was initially created for searching of optical partners of gamma ray bursts [5,7]. The system
is located in Chile and consists of two CCD cameras on a common mounting base . Currently, it performs various
astronomical observations [1,5,7,8]. Among others, system also records passages of satellites and fragments of Earth's
artificial satellites, so called "space debris". Since now, this kind of data was identify as a disturbing transient signal and
team members usually focus on identify and eliminating it. Handle of this problem is especially important, because
software algorithm which search for optical companion of gamma ray bursts focus on transient phenomena events.
On the other hand, comparison of the "Pi of the Sky" system parameters with different facilities which are used for
space debris searching and monitoring shows, that its properties are similar to some of those systems. It means, that it
should be possible, to obtain valuable data of artificial satellites motion analyzing "Pi of the Sky" data. Moreover,
expected in the near future system upgraded to 6 small telescopes equipped totally with 24 CCD detectors system 
will cover a major part of the sky (field of view of each detector equals 20 x 20 degrees) which gives possibility of
visual measurements objects up to 16 magnitude. It will be an unusual advantage in the field of system categories with
that size. In the paper, we would like to shortly describe a space debris community activities, present properties of
selected systems which are using for space debris surveys and finally examples of observational data will be presented.
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.
The Pi of the Sky experiment, located at Las Campanas Observatory in Chile, searches for rapidly changing optical
objects such as optical counterparts of Gamma Ray Bursts. The system consists of two CCD cameras placed on
parallactic mount and operated by a PC equipped with dedicated software. The data acquired is reduced and essentially
only the brightness of stars is stored in the database. A web interface for the star databases offers easy and quick access
to the experiment's data and to other star catalogs that are also stored in our databases.
Based on the data from the "Pi of the Sky" project a catalog of variable stars with a period from 0.1 to 10 days
was prepared. We analyzed data collected during the period of two years (2004 and 2005) and we identified 725
variables stars. Most of the stars in our catalog are classified as eclipsing binaries - 464 (about 64%) while the
number of pulsating stars is 125 (about 17%). Our classification was based on the shape of the light curve, as
in the GCVS catalog. However, some stars from the GCVS catalog were classified differently in our catalog. We
found periods for 15 stars included in GCVS catalog as stars with yet unknown period and absent in the ASAS
A robotic system for continuous observation of a night sky is proposed. The "Full Pi of the Sky" system will consist of 32 CCD cameras and 8 motorized parallaactic mounts. The location of a future observation site requires full remote control and autonomous on-line and off-line data analysis. Inorder to test scalability of the sytem and to develop optimal control and analysis algorithms a full, real-time jardware simulation will be employed. The concept of the "Full Pi of the Sky" architecture and some aspects of its software emulation are discussed in this paper.
The main aim of the "Pi of the Sky" experiment is to search for optical flashes associated with the gamma ray bursts.
The detector also allows us to study other kinds of short timescale astrophysical phenomena. During everyday
observations "Pi of the Sky" detector collects many measurements of interesting objects like blazars, quasars, variable
stars etc. It is very important to make this data available to other experiments as fast as possible. Dedicated WWW
interface connected with the "Pi of the Sky" database in Chile was created to provide on-line access to selected objects.
The interface allows quick and easy accesses to the "Pi of the Sky" data right after all measurements processes are
The large amount of data collected by the automatic astronomical cameras has to be transferred to the fast computers in a reliable way. The method chosen should ensure data streaming in both directions but in nonsymmetrical way. The Ethernet interface is very good choice because of its popularity and proven performance. However it requires TCP/IP stack implementation in devices like cameras for full compliance with existing network and operating systems. This paper describes NUDP protocol, which was made as supplement to standard UDP protocol and can be used as a simple-network protocol. The NUDP does not need TCP protocol implementation and makes it possible to run the Ethernet network with simple devices based on microcontroller and/or FPGA chips. The data transmission idea was created especially for the "Pi of the Sky" project.
There is currently no experiment running that can perform non-accidental observations of Gamma Ray Bursts (GRB) optical counterparts from their very beginning, not mentioning seconds before the GRB. The main reason is the time that even small telescopes need for moving to the burst coordinates after receiving a trigger from a satellite and the time of the trigger propagation itself. "π of the Sky" project overcomes this obstacle by introducing an array of CCD cameras aimed at simultaneous observations of large sky area - and thus the location of the GRB source during and even before the burst itself. The price for this solutions is, however, a lower magnitudo range, reaching only about 14m - 15m. In this paper we present a preliminary analysis, based on most of the currently available optical lightcurve measurements, indicating that a significant fraction of GRB optical counterparts should lie in this range.
The main aim of the "Pi of the Sky" experiment is a search for short optical transients in the sky. During each night the whole sky is scanned two times, at the beginning and at the end of the night. This paper describes the basic analysis carried out on the sky scan data and its preliminary results.
Modern astronomical image acquisition systems dedicated for sky surveys provide large amount of data in a single measurement session. During one session that lasts a few hours it is possible to get as much as 100 GB of data. This large amount of data needs to be transferred from camera and processed. This paper presents some aspects of image acquisition in a sky survey image acquisition system. It describes a dedicated USB linux driver for the first version of the "Pi of The Sky" CCD camera (later versions have also Ethernet interface) and the test program for the camera together with a driver-wrapper providing core device functionality. Finally, the paper contains description of an algorithm for matching several images based on image features, i.e. star positions and their brightness.
Modern research trends require observation of fainter and fainter astronomical objects on large areas of the sky. This implies usage of systems with high temporal and optical resolution with computer based data acquisition and processing. Therefore Charge Coupled Devices (CCD) became so popular. They offer quick picture conversion with much better quality than film based technologies. This work is theoretical and practical study of the CCD based picture acquisition system. The system was optimized for "Pi of The Sky" project. But it can be adapted to another professional astronomical researches. The work includes issue of picture conversion, signal acquisition, data transfer and mechanical construction of the device.
This paper describes databases used in the Pi of the Sky experiment, particularly the databases of stars and observations. The Pi of the Sky experiment, located at Las Campanas Observatory in Chile searches for rapidly changing optical objects such as Gamma Ray Bursts (GRB). The system consists of two CCD cameras placed on paralactic mount and operated by a PC, equipped with dedicated software. The data acquired is reduced and mainly the brightness of stars is stored in the database. A web interface for the database has been created. It allows easy and quick access to the experiment's data and to other star catalogs, which are also included in our databases.
The main aim of the "π of the Sky" project is all night monitoring of a large sky area in search for GRB optical counterparts. Contrary to the most of existing experiments, "π of the Sky" does not rely on satellite GRB triggers only, but independently detects optical flashes in the sky and later seeks an association with a satellite alert. This approach requires an efficient self-triggering system, capable of reducing the rate of flash candidates to an amount suitable for a human-eye analysis. This paper covers main aspects of our flash recognition algorithms, briefly describing main false event types that are encountered as well as cuts designed to eliminate them. Physical results based on the data gathered by the "π of the Sky" apparatus prototype during it's first year of operation are presented.
This paper describes PiMan, a CORBA based system manager of the "Pi of the Sky" experiment. The "Pi of the Sky" experiment, located at Las Campanas Observatory in Chile searches for rapidly changing optical objects such as Gamma Ray Bursts (GRB). The system is composed of two CCD cameras located on paralactic mount and operated by a PC, equipped with the dedicated software. The software, divided into modules that correspond to hardware or logical components, controls all aspects of data collection and on-line data analysis. The PiMan assures communication between modules, coordinates their behavior and gives possibility to operate the system automatically and to control it remotely over low bandwidth and unstable link.
The detector "Pi of the Sky" searches for optical flashes in the sky. Its main goal is to look for optical afterglows associated with gamma ray bursts (GRB), but it also has a capability to detect other phenomena like variable stars. Collected data passes through a specially designed software pipeline. At last. a collection of stars' light curves is obtained and put into a database. At this level it is possible to study stars and analyse their variability. Example results are presented.
"Pi of the Sky" is a detector designed for search for optical flashes of cosmic origin in the sky. Its primary goal is to look for optical afterglows associated with the gamma ray bursts (GRB) but it is capable to detect also other optical transients of extragalactic origin. The apparatus consists of two arrays of 16 cameras each, which allow for simultaneous observation of large part of the sky. Thanks to on-line data analysis in real time, it has self-triggering capability and can react to external triggers with negative time delay. The prototype with two cameras has been installed at Las Campanas (Chile) and is operational from July 2004. General idea of experiment, the apparatus and its performance will be presented.
Effective search for gamma ray bursts optical counterparts and other fast astrophysical phenomena requires robotic telescopes. Such telescopes have to be able to realise programmed survey schedule and to react to various kind of alerts. Robotic telescope used in the prototype phase of the "Pi of the Sky" project is described.
Design of the full size detector is briefly presented.
The "Pi of the Sky" project is an attempt to create fully autonomous system for detection and analysis of optical flashes in the sky at the time scale of seconds, which are connected with gamma ray burst (GRB). This paper presents briefly the "Pi of the Sky" observing strategy. Test toolkits for schedule scripts and sky scans is described. Application of web services technology for data analysis in the experiment is discussed.
"Pi of the Sky" is a detector designed for search for optical flashes of the cosmic origin in the sky. Its primary goal is to look for optical afterglows associated with the gamma ray bursts (GRB), but it is capable to detect also other optical transients of extragalactic origin. The apparatus consists of two arrays of 16 cameras each, which allow for simultaneous observation of the whole sky. Due to on-line data analysis in the real time, it has self-triggering capability and can react to external triggers with negative time delay. The prototype with two cameras has been installed at Las Campanas (Chile) and is operational from July 2004. General idea of experiment, the apparatus and its performance will be presented. Physical results will be reviewed and perspectives for the future will be outlined.
We present optimized performance of algorithms developed for detection of point like, visible light bursts in the sky. The algorithms based on analysis of series of consequtive images and detecting local differences between them were tested on simulated data obtained by inserting images of stars of different magnitudes at random positions. We discuss the choice of parameters which results in the maximal detection efficiency and simultaneously keeps the number of false detections as low as possible.
Perhaps the most powerful cosmic processes ever observed are gamma ray bursts (GRB). So far, phenomena responsible for GRB have not been unambiguously identified. In the present paper we propose an approach completely different from the classical one. It employs experimental techniques developed for particle physics. Presented project is pioneering research in the unexplored so far domain of cosmic phenomena on the time scale of seconds. Both the rate of signal in question and the rate of unexpected background are not known. Therefore we decided to divide the project into two phases: phase I -- two CCD cameras, phase II - a system of cameras covering all sky. The phase I is well defined whereas detailed realization of phase II will depend strongly on results and experience gained in phase I.