ASTRONOMICAL ARCHIVES USED FOR NEO PRECOVERY WORK

This section is dedicated to Astronomical Archives used for NEO precovery work and consists in a network of links about the activities and the archives used by a few dedicated teams.

This page is organized in a very simple way. After a brief hystorical review of what has been done in the past and why archives are so important for NEO work, we provide four general listings that include: i) general archival resources; ii) a review of the teams/individuals involved in precovery work; iii) a collection of archives currently used in NEO precovery work, both photographic and CCD.

Hystorical Review and the Importance of Archives

Precovery searching for minor bodies (comets and asteroids) is not a new activity since it has led to scientifically valuable results in the recent past. For example, the identification of the Amor-type object (4015) = 1979 VA with Periodic Comet Wilson Harrington (1949 III) on two plates from the First Palomar Sky Survey ( Bowell 1992), showed clear evidence that the distinction between asteroid and comets is not very straightforward. The well-known comet Hale-Bopp had its orbital solution significantly improved thanks to precovery data obtained during the early stages of the follow-up process ( McNaught 1995).

The interest for astronomical archives has grown significantly in the NEO community in the past few years. This is because studies and discussions among scientists have concentrated more and more on the hazard aspect of these bodies. It is becoming clearer and clearer that hazard mitigation requires much more than just discovery: there is a need to obtain very good orbits of NEOs in the shortest possible time. The inspection of astronomical archives is one of the most interesting and rapid methods to meet this goal. It was aptly demonstrated recently when two km-sized NEOs, 1997 XF11 and 1999 AN10, were found to have very small collisions probabilities with the Earth. The collision solutions could be excluded with data from photographic archives.


Current situation

After the pioneer efforts of the Anglo-Australian Near-Earth Asteroid Survey (AANEAS) in 1990-1996, newly discovered NEOs are now routinely searched for on some archival resources (mostly photographic) by a variety of dedicated programs. These initiatives have benefited from one obvious factor in common: access to some local archival resouces. Part of their success is that they could conduct this activity without travelling around the world, because the working team either:

  • Owns the plate collection.
  • Is based where the plates are stored.
  • Remotely retrieves archival material in a digital form on the internet.
By using these available options the teams involved in archival searches have managed to secure the orbit of almost 200 of the more than 500 multiple-opposition NEAs currently known (as of October 18, 2001). About 80 % of these identifications was made in the past two years alone, mostly by DANEOPS and ANEOPP: 90 % of these were made on photographic archives and 10 % on CCD resources. It is clear that CCD can even play a more important role in the coming years if data is appropriately preserved and made available to the community.

Teams and individuals currently involved in this activity


Here we provide a list of people and teams involved in NEO precovery work. Some of them carry out this activity systematically, maintaing a costant level of attention on all the newly discovered NEOs. Part of their activity is also devoted to main-belt objects (MBOs), as well as other unusual objects.

Other individuals, who may have access to additional archives have been willing to look for specific objects, but they do not currently carry out a systematic effort for all the known NEOs. Further occasional collaborators come from astronomers not too expert in the field they may need some assistance during their initial experiences.


Each team/individual is flagged with a three letter designation (in parenthesis) that will be used later in the list of archives currently available for work.

While the DANEOPS team is rapidly incresing the number of archival collections available for their work, at the SCN we have been trying to expand the number of people who are willing to collaborate on an occasional basis, so that a wider range of archives could be accessed. In addition to targeted efforts, a collaboration can result in planning work visit where these archives are stored for a more systematic work.

General Archival Resources

  • The Wide-Field Plate Database (WFPDB) - CDS contains the descriptive information for the astronomical wide-field (~>1 deg.) photographic observations stored in numerous archives all over the world. The Catalogue of Wide-Field Plate Archives (WFPA) is prepared in the Institute of Astronomy at the Bulgarian Academy of Sciences within the activities of the IAU Commission 9 Working Group on Wide-Field Imaging, founded in 1991.

  • The UDAPAC project: Uccle Direct Astronomical Plate Archive Centre. It was born in March 2000 with the goal to digitize about half million direct photographic plates in a time frame of 5 years.

Archives used for NEO precovery work

    There are several hundred of photographic archival collections, consisting of more than two million of plates all over the world. Only a minor fraction of these are really suitable for NEO work and a smaller percentage of this is available in some way to the community for investigation and study. In the following scheme we have divided the archives available (both photographic and CCD) into three catgories:

    • (A) - archives directly accessible at any time (at least for one team) Precovery plans for NEOs with large uncertainties can be set-up ahead of time and pursued until success if there are indeed images that contain the desired object.

    • (B) - archives not directly accessible at any time, but data can be retrieved through various forms of collaborations. Activity generally limited to objects with small uncertainty or more improtant for the community.

    • (C) - archives not directly accessible at any time and data may not be retrieved at all, either because of lack of personell or impossibility to find a particular plate. Sometime all is available is a catalogue on file or simply on paper. A dedicated project or a funding program may be needed to extract data from these resources.

    For each archive we put its category of accessibility and the designation of the teams that have been using it. The category may vary from team to team since it might be better accessible for some people than for other.

  • The Digital Sky Survey

    In order to fully exploit their scientific potential, astronomers realized that photographs must be converted into a digital format, suitable for computer analysis. This led to the Digital Sky survey or DSS, a project carried out at the Space Telescope Science Institute (STScI).

  • The role of the Digital Sky Survey

    The Digital Sky Survey is like a virtual observatory. It is the result of a large project, consisting in the digitization of a set of high-quality plates.The project goal was to map the entire sky in different colours, typically blue, red and near-infrared. Three telescopes have been employed in this task: the 1.2-m Oschin Schmidt telescope, the 1.2-m UK Schmidt telescope in Australia and the 1.1-m ESO Schmidt telescope in Chile.

    The role of DSS has gone well beyond the work on NEOs. This great resource has been used to locate and measure thousands of main-belt objects. This served both the purposes of confirming many uncertain identifications and of speeding the process of numbering these bodies by the Minor Planet Center.


  • Photographic Archives

    • POSS-I - First Palomar Sky Survey (1949-1958) - (part of DSS I) :

      (A) - DAN - ANP - ALW - RHP

    • POSS-II - Second Palomar Sky Survey (1985-1999) - (part of DSS II) :

      (A) - DAN - ANP - ALW - RHP

    • POST - Palomar Oschin Schmidt Telescope (1958-1985) :

      (B) - PCS : (C) - ANP

    • UKSTU - UK Schmidt Telescope Unit archive (1973-2001) - (part of DSS I and II)

      Survey plates: (A) - ANP - DAN - RHM - ALW - RHP
      Non survey plates: (B) - ANP - RHM - DJA

    • ESO-ST - European Southern Observatory Schmidt Telescope (1974-1997):

      (A-B) - DAN : (B-C) ANP

    • ESO-WFI - European Southern Observatory - WFI, ASTROVIRTEL project. -- ESO-ST :

      (A) - DAN

    • PCAS - The Palomar Planet-Crossing Asteroid Survey (1973-1995):

      (A) - PCS

    • PACS - The Palomar Asteroid and Asteroid Survey (1983-1995):

      (A) - LOW : (B) ANP - DAN

    • Indiana Goethe Link - Indiana Goethe Link plates: (A) - LOW

    • PLUTO CAMERA - Pluto Camera - Lowell Observatory: (A) - LOW

    • LICK-AS - Lick Observatory Double Astrograph (1941-1988) :

      (B) - AKL : (C) ANP

    • KISO - Kiso Schmidt telescope archive : (B) - DJA

    • Tautenberg - Tautenberg Schmidt telescope archive : (B) - DAN

    • Sonneberg - Sonneberg Schmidt telescope archive: (B) - DAN

    • Bigelow Sky Survey - Bigelow Schmidt telescope archive : (B) - DAN

    • Uppsala Sky Survey - Uppsala Schmidt telescope archive : (B) - DAN

    • Kvistaberg Sky Survey - Kvistaberg Schmidt telescope archive : (B) - DAN


  • CCD Archives

    Although NEO dedicated programs have been sweeping huge region of the celestial sky by means of powerful CCD cameras at various limiting magnitudes in these last few years, the number of available CCD archival resources is still very limited.

    • NEAT - Near-Earth Asteroid Tracking : 1.2-m reflector : (A) DAN - RHP

    • CFHT - Canada-France Hawaii Telescope : 3.6-m reflector : (A) DAN

    • AAT - Anglo-Australian Telescope : 3.9-m reflector : (A) RHM - DAN

    • SLOAN SDSS - Apache Point Observatory : 2.5-m reflector : (A) DAN

    • Spacewatch - Spacewatch telescopes : 0.9-m and 1.8-m reflectors, Kitt Peak Observatory :

      (B) SCN - only limited pointing history data

    • LONEOS - LONEOS telescope : 0.6-m Schmidt, Lowell Observatory :

      (B) SCN - only limited pointing history data

Further Useful Links

Publications

The following papers have discussed precovery work on minor planets, with special emphasis on NEOs:

  • Boattini A., D'Abramo G., Forti G., Gal R., 2001, Astronomy & Astrophysics, 375, pp. 293-307

  • McNaught R. H., Steel D. I., Russell K. S., Williams G. V., 1995, IAU Colloquium 148: The Future Utilization of Schmidt Telescopes , pp. 170-173

  • Steel D. I., McNaught R. H., Garradd G. J., Asher D. J., Russell K.S., 1997, Australian Journal of Astronomy, 7, pp. 67-77


Acknowledgements


We want to thank A. Doppler, A. Gnadig, R. Stoss, A. Lowe, R. McNaught, D. Asher and B. Skiff for providing comments and useful information about their precovery activities. The information in this page is still incomplete and might be affected by several errors. We apologize for that and hope to have your useful comments. Some of the links from this page are not active yet.


This document was updated on February 19, 2002, by Andrea Boattini and Germano D'Abramo