Baltic
Astronomy,
vol. 6, 271-274,
1997.
THE WIDE-FIELD PLATE DATABASE :
P R E S E N T STATUS AND F U T U R E
DEVELOPMENT
M . K . Tsvetkov 1 , K . Y . Stavrev 1 , K . P . Tsvetkova 1 , E.H. Semkov 1 ,
A. S. Mutafov 2 and M.-E. Michailov2
Institute of Astronomy,
Bulgarian Academy of Sciences,
72
Tsarigradsko
Shosse Blvd., BG-1784 Sofia,
Bulgaria
2Astronomical
Observatory,
Sofia University,
Sofia 1504, Ρ·0.
Box 36,
Bulgaria
1
Received July 20, 1996.
Abstract. The current status and future development of the WideField Plate Database, which is in preparation at the Institute of Astronomy in Sofia, are described. The database will be centralized
and will provide on-line access to the information on about 2 million
photographic observations.
K e y words:
databases - plate archives
1. INTRODUCTION
The Wide-Field Plate Database (WFPDB), which has been in
preparation during the last few years at the Institute of Astronomy
of the Bulgarian Academy of Sciences, is a register of the wide-field
( > I o ) photographic observations stored in numerous archives all over
the world. It will be centralized and will provide on-line access to
the information on about 2 million observations obtained since the
end of the last century. Previous descriptions of the W F P D B can be
found in Tsvetkov et al. (1994, 1995).
2. C U R R E N T VOLUME OF T H E W F P D B
The W F P D B is generated by merging the data from a number of
original plate catalogs provided to us by the institutions possessing
archives of wide-field observations. Table 1 shows the number of
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M. Κ. Tsvetkov, Κ. Y. Stavrev, Κ. P. Tsvetkova, Ε. H. Semkov et al.
observations incorporated in the database up to June 1996 compared
with the total number of wide-field observations. At present, 281
archives all over the world contain a total of nearly 1900 000 widefield plates and films. The W F P D B already includes the data from
more than 400 000 of them. Thus, the completeness of the W F P D B
has reached 20%. Note that almost half of all wide-field observations
(about 900 000) axe still not catalogued in computer-readable form
at the institutions where they are archived and this imposes certain
restrictions on the rate at which the W F P D B can be completed.
Fig. 1 shows a sky map of the W F P D B observations in equatorial
coordinates (equal-area projection).
T a b l e 1. The number of plates in the Wide-Field Plate Archives (WFPA)
and in the WFPDB (June 1996).
Archives
WFPA
WFPDB
281
87
Instruments Observatories Plates
93
1886200
219
73
28
405 280
Fig. 1. All-sky distribution of the WFPDB observations.
3. W F P D B CONTENT AND DATA REDUCTION
For each observation the W F P D B provides information including a reference to the corresponding archive, parameters of the observational instrument, observation parameters (position on the sky,
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The Wide-Field
Plate
Database
273
observation time, object name, etc.), as well as plate quality, comments, observer and plate availability.
Prior to incorporating into the WFPDB, the data from the original plate catalogs undergo a complex reduction procedure aimed
at standardization of the observation parameters, including coordinate and time transformations to J2000 and UT; standardization
of object, emulsion and filter designations; decoding of coded data;
translation of notes if they are not in English; correction/marking
of errors; supplementing/marking of missing data and structuring of
non-structured data.
As a result of this reduction, the data originating from a large
number of very different plate catalogs appear in the W F P D B in
a homogenized form. The WFPDB thus allows easy extraction of
complete and correct sets of observations obtained with selected instruments within selected sky areas and time intervals.
4. ACCESS AND DATA RETRIEVAL
The WFPDB is installed on a PC 486 DX4/100 under the management of MS ACCESS 7.0.
At present we provide only a limited access to the WFPDB.
The data on the archives and the corresponding observational instruments - the so-called List of Wide-Field Plate Archives (LWFPA)
- are available from the WFPDB WWW home page located under
URL at http://www.wfpa.acad.bg. The data on individual observations are currently accessible only in batch mode by user requests
sent to wfpdbQwfpa. acad. bg. Search results are sent to the users as
ASCII files.
5. FUTURE DEVELOPMENT
First of all, we expect a considerable enlargement of the
WFPDB. One of the sources of new data is the Harvard College
Observatory Plate Collection, which is the largest plate archive in
the world, containing 500 000 plates. About 50 000 of these are already catalogued in machine-readable form. We also anticipate a
flow of data from archives that do not possess machine-readable catalogs of observations. In this case the data will be converted into
electronic form by the WFPDB team.
Another important development of the WFPDB will be its installation on a Hewlett Packard 9000/712/80 workstation under the
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M. Κ. Tsvetkov, Κ. Y. Stavrev, Κ. P. Tsvetkova,
Ε. H. Semkov et ai
management of the ORACLE DBMS version 7.2.2.3.0 with search
and sampling based on SQL commands.
After this reorganization of the database, access to it will be
provided online through the Internet.
ACKNOWLEDGMENTS. This work was supported by grants
F-311/93 and 1-529/95 from the National Science Foundation of the
Bulgarian Ministry of Education, Science and Technologies, Alexander von Humboldt Stiftung (Germany), the Computer Center and
the Astronomical Institute of the Westfaelische-Wilhelms University,
Muenster (Germany).
One of us (K.Y.S.) is very grateful to the LOC of the St.
Petersburg Colloquium for partial support that allowed him to attend it.
REFERENCES
Tsvetkov M.K., Stavrev K.Y., Tsvetkova K.P., Ivanov P.V., Iliev M.S.
1994, in Astronomy from Wide-Field Imaging (Proc. IAU Symp.
No. 161), eds. H.T.MacGillivray et al., Kluwer Academic Publishers,
Dordrecht, p. 359
Tsvetkov M., Stavrev K., Tsvetkova K., Mutafov Α., Michailov M.-E.
1995, in The Future Utilisation of Schmidt Telescopes (Proc. IAU
Coll. No. 148), eds. J.M. Chapman et al., ASP Conf. Ser., vol. 84,
p. 148
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