Archives of Photographic PLates for Astronomical USE

Archive - Baldone Astrophysical Observatory

General Information

Baldone Schmidt telescope (80/120/240 cm), one of the 12 largest Schmidt telescopes worldwide

operating since December 1966 on the Riekstukalns hill (lon = +24°24.0', lat = 56°47', alt = 75 m) near Baldone town (Latvia)

first photographic plates obtained in January 1967

entire operation period: 1967–2001

mostly covering the zone along the galactic equator

plate archive at the Astrophysical Observatory of the Institute of Astronomy of the University of Latvia

the glass and film plates are stored vertically in the rooms of the Schmidt telescope dome in original ORWO 24×24 cm size plate packing boxes, arranged in chronological sequence

used emulsions: mostly ORWO Astro ZU1, ZU2, ZU21, ZP1, ZP3 and Russian A500, A600, A700

used bandpasses: U, B, V, Becker R, Kron I

Schmidt plates

~22000 plates of size 24×24 cm with field of view 4°46' in diameter

more than 160 combinations of filters and emulsions

image scale 72"/mm

Spectral plates

~3000 plates

obtained using 2° and 4° objective prisms of 80 cm diameter

reciprocal dispersion of 1130 Å/mm, resp. 600 Å/mm at the Hγ line

more than 110 combinations of filters and emulsions

Catalogues and Digitization

the entire plate catalogue is available in a computer readable form with 12 data columns:

- plate number - date before midnight of the observation night - object designation - equatorial right ascension - equatorial declination - exposure start time - exposure duration in minutes - emulsion type - filter type - photometric passband - codes for cloud-interrupted or multiple-exposure observations - codes for auxiliary equipment used in observation

a separate list of objects observed (with more than 1300 objects for direct and more than 600 objects for spectral plates) with 7 data columns:

- sequential object number - object designation - equatorial right ascension - equatorial declination - plate number of the chronologically first observation - date of the chronologically first observation - total number of plates for the object

digitization started in 2012 with Epson Expression 10000XL flatbed scanner with 2400 dpi, 4000 plates are digitized, approximately ~900 MB per digitized plate, IRAF packages used for data processing

preliminary image reduction in MIDAS/ROMAFOT to obtain x-y pixel coordinates and instrumental magnitude estimations of fixed objects

no online database available so far

Description based on:

Alksnis, A. et al. Baldone Schmidt Telescope Plate Archive and Catalogue in: Baltic Astronomy, vol. 7, pp. 653–668 (1998). Eglitis, I. Baldone Schmidt telescope astronomical photos archive (poster) (abstract)