All Sky Automated Survey
Encyclopedia
Poland
Poland , officially the Republic of Poland , is a country in Central Europe bordered by Germany to the west; the Czech Republic and Slovakia to the south; Ukraine, Belarus and Lithuania to the east; and the Baltic Sea and Kaliningrad Oblast, a Russian exclave, to the north...
project implemented on 7 April 1997 to do photometric monitoring of approximately 20 million star
Star
A star is a massive, luminous sphere of plasma held together by gravity. At the end of its lifetime, a star can also contain a proportion of degenerate matter. The nearest star to Earth is the Sun, which is the source of most of the energy on Earth...
s brighter than 14 magnitude
Magnitude (astronomy)
Magnitude is the logarithmic measure of the brightness of an object, in astronomy, measured in a specific wavelength or passband, usually in optical or near-infrared wavelengths.-Background:...
all over the sky. The automatic telescope
Telescope
A telescope is an instrument that aids in the observation of remote objects by collecting electromagnetic radiation . The first known practical telescopes were invented in the Netherlands at the beginning of the 1600s , using glass lenses...
s discovered two new comet
Comet
A comet is an icy small Solar System body that, when close enough to the Sun, displays a visible coma and sometimes also a tail. These phenomena are both due to the effects of solar radiation and the solar wind upon the nucleus of the comet...
s in 2004 and 2006. The ASAS-South, located in Chile
Chile
Chile ,officially the Republic of Chile , is a country in South America occupying a long, narrow coastal strip between the Andes mountains to the east and the Pacific Ocean to the west. It borders Peru to the north, Bolivia to the northeast, Argentina to the east, and the Drake Passage in the far...
and ASAS-North, located in Hawai'i, are managed by Grzegorz Pojmański
Grzegorz Pojmanski
Dr Grzegorz Pojmański , Polish astronomer, worker of Warsaw University Astronomical Observatory, Poland. In 1997 Pojmański together with professor Bohdan Paczyński implemented the project All Sky Automated Survey . With the ASAS Alert System Pojmański discovered two new comets: C/2004 R2 and...
of the Warsaw University Observatory via the internet
Internet
The Internet is a global system of interconnected computer networks that use the standard Internet protocol suite to serve billions of users worldwide...
.
The idea was initiated by the Polish astronomy Professor Bohdan Paczyński
Bohdan Paczynski
Bohdan Paczyński or Bohdan Paczynski was a Polish astronomer, a leading scientist in theory of the evolution of stars, accretion discs and gamma ray bursts....
of Princeton University
Princeton University
Princeton University is a private research university located in Princeton, New Jersey, United States. The school is one of the eight universities of the Ivy League, and is one of the nine Colonial Colleges founded before the American Revolution....
. The prototype instrument and data pipeline were designed and built by Grzegorz Pojmański. The work on the ASAS program began in 1996 with a mere $1 million budget. The automatic telescope, located in Las Campanas Observatory
Las Campanas Observatory
Las Campanas Observatory is an astronomical observatory owned and operated by the Carnegie Institution for Science It was established in 1969 and remains the primary observing site of that institution. The headquarters is located in La Serena, Chile and the observatory is in the southern Atacama...
, Chile, was designed to register the brightness of circa one million stars in the Southern Hemisphere
Southern Hemisphere
The Southern Hemisphere is the part of Earth that lies south of the equator. The word hemisphere literally means 'half ball' or "half sphere"...
. However, it proved very efficient and helped to find many new variable stars. The project was then expanded, and now operates four telescopes located in Las Campanas Observatory. The Chilean observatory is operated by the Carnegie Institution of Washington.
So far, ASAS has discovered 50,000 variables located south of declination +28°, which means that it has covered 3/4 of all the sky. Pojmański comes to Chile only once every year. The telescope works automatically. Routine work such as exchanging of the data is done by the Optical Gravitational Lensing Experiment (OGLE)
Optical Gravitational Lensing Experiment
The Optical Gravitational Lensing Experiment or OGLE is a Polish astronomical project based at the University of Warsaw that is chiefly concerned with discovering dark matter using the microlensing technique. Since the project began in 1992, it has discovered several extrasolar planets as a side...
observers. Such an intervention is needed once a week. On each starry night when an OGLE observator opens or closes the dome, the ASAS booth is opened or closed automatically.
Grzegorz Pojmański is supported in the project by the State Committee for Scientific Research, Poland. The project is assisted by OGLE observers. Paczyński was supported by William Golden.
The ASAS 1-2 systems
The prototype ASAS instrument, equipped with 768x512 Kodak CCDCharge-coupled device
A charge-coupled device is a device for the movement of electrical charge, usually from within the device to an area where the charge can be manipulated, for example conversion into a digital value. This is achieved by "shifting" the signals between stages within the device one at a time...
and 135/1.8 telephoto lens, and mounted on the computer controlled robotic mount, operated from 7 April 1997 until 6 June 2000. Prototype took about 15 3-minute exposures (covering 90 sq. deg.) per hour (over 120 per night) with limiting I-magnitude 13 and resolution of 14 arcsec/pixel. Initial setup consisted of 24 fields covering 150 sq. deg. (later increased to 50 fields - 300 sq. deg) monitored few times each night.
ASAS 2 results obtained during 1997-2000 available at the ASAS website contain:
- The ASAS-2 Photometric I-band Catalog - giving interactive access to over 50 million measurements of over 140,000 stars,
- Sky Atlas - graphic interface to the I-band Catalog,
- The ASAS-2 Catalog of Variable Stars containing over 350 Periodic and 3500 Miscellaneous variables,
- The ASAS Gallery presenting collection of the variables' light curves.
The ASAS-3 system
On 6 June 2000 the ASAS-3 system replaced the low cost prototype. It consists of two wide-field 200/2.8 instruments, one narrow-field 750/3.3 telescope and one super-wide 50/4 scope. Each of them is equipped with the Apogee 2Kx2K CCD camera, located in the custom made automated enclosure.In April 2002 ASAS-3 was expanded and is now housing four instruments. The fourth one is a very-wide-field scope equipped with the 50 mm lens and another AP-10 camera. It features 36x26 deg. FOV and observes only a few selected fields in purpose to test instrument sensitivity for fast transient events.
ASAS-3 is directly connected to the BACODINE network and is ready for immediate follow-up observations of GRB events.
ASAS-3 results obtained since the year 2000 are available at the ASAS website:
- The ASAS-3 Catalog of Variable Stars containing over 10,000 eclipsing binaries, almost 8,000 periodic pulsating and over 31,000 irregular stars found among 15,000,000 stars on the sky south of the declination +28.
Selected discoveries
Number of stars observed by ASAS: approx. 15 million. Number of detected variables: approx. 50,000. Number of new variables: approx. 39,000.Comets
- C/2006 A1 (Pojmański)Comet PojmanskiComet Pojmański is a non-periodic comet discovered by Grzegorz Pojmański on January 2, 2006 and formally designated C/2006 A1. Pojmański discovered the comet at Warsaw University Astronomic Observatory using the Las Campanas Observatory in Chile as part of the All Sky Automated Survey...
- the new comet was discovered by the ASAS Alert System on 2 January 2006 on the image taken on 1 January. Confirmation images were taken on 4 January, and one prediscovery image was identified on 29 December 2005. - C/2004 R2 (ASAS) - the new comet was discovered by the ASAS Alert System on 7 September 2004. Confirmation images were taken on 8 September and one prediscovery image was identified on 1 September .
Novae
- Nova SMC = ASAS 011500-7325.6 (predisc. autom. detect.)
- V1663 Aql = Nova Aql = ASAS 190512+0514.2 (ASAS discovery)
- V378 Ser = Nova Ser 2005 = ASAS 174924-1300.0 (ASAS discovery)
- V5114 Sgr = Nova Sgr 2004 = ASAS 181932-2836.6 (predisc. autom. detection)
- V2574 Oph = Nova Oph 2004 = ASAS 173845-2328.3 (predisc. autom. detection)
- V1186 Sco = Nova Sco 2004 = ASAS 171251-3056.6 (ASAS discovery)
- V1188 Sco = Nova Sco 2005 = ASAS 174422-3416.5 (ASAS discovery)
- V477 Sct = Nova Sct 2005 Number 2 = ASAS 183843-1216.3
Dwarf Novae
- ASAS 160048-4846.2 - UGSU in Nor (ASAS discovery)
- ASAS 091858-2942.6 - CV in Pyx (ASAS discovery)
- ASAS 153616-0839.1 - UGWZ (ASAS discovery)
- ASAS 002511+1217.2 - UGWZ/UGSU ? (ASAS discovery)
(predisc. autom. detection) = object was independently detected by the ASAS Alert System before official discovery, but was not verified by a human until later.
ASAS Alert System
Since 1 March 2003 the ASAS data reduction pipeline is working in real time. All photometric data is available through a web interface within 5 minutes after exposure.ASAS publications
- Eclipsing binaries in ASAS catalog by B. Paczyński, D. Szczygieł, B. Pilecki, G. Pojmański
- The All Sky Automated Survey. The Catalog of Variable Stars. V. Declinations 0 deg - 28 deg of the Northern Hemisphere by G. Pojmański, B. Pilecki, D. Szczygieł
- The All Sky Automated Survey. The Catalog of Variable Stars. IV.18^h - 24^h Quarter of the Southern Hemisphere by G. Pojmański, Gracjan Maciejewski
- The All Sky Automated Survey. The Catalog of Variable Stars. III. 12h - 18h Quarter of the Southern Hemisphere by G. Pojmański, Gracjan Maciejewski
- The All Sky Automated Survey. The Catalog of Variable Stars. II.6h-12h Quarter of the Southern Hemisphere by G. Pojmański
- The All Sky Automated Survey. A Catalog of almost 3900 variable stars by G. Pojmański
- The All Sky Automated Survey. Variable Stars in the 0h - 6h Quarter of the Southern Hemisphere by G.Pojmański
- The All Sky Automated Survey. The Catalog of the Short Period Variable Stars in the Selected Fields by G. Pojmański
- The All Sky Automated Survey by G. Pojmański