VIIth Bulgarian-Serbian Astronomical Conference (VII BSAC):

1- 4 June, 2010, Chepelare, Bulgaria

DIGITIZING OF THE ASTRONOMICAL PHOTO PLATES IN

THE NATIONAL ASTRONOMICAL OBSERVATORY ROZHEN

Nikola Petrov, Asia Tzvetkova,  Milcho Tsvetkov

Institute of Astronomy and National Astronomical Observatory ROZHENBulgarian Academy of Sciences, Bulgaria

Abstract

The structure and capabilities of computer network in the National Astronomical Observatory Rozhen were carried out. Described is a method and hardware to scan the astronomical observational material on photo plates obtained by telescopes at the Institute of Astronomy, Bulgarian Academy of Sciences. Observations cover the period 1979-1998. Digital representation of the observations is part of the Virtual Astronomical Database.

Computer network in the National Astronomical Observatory Rozhen

Wireless connection

4 MB transfer

Scanning process of astro-platesand create of data base

Askoiris tool for photometric studies of astronomical observations on photo-plates of NAO Rozhen. Measurements were made until 1997.

The first professional scanner-microdensitometer in NAO Rozhen. Similar to that instrument in Bulgaria are only 3. During 1999 in the Institute of Astronomy, Sofia is installed the next generation matrix scanner – PDS.

Epson Expression 10000XL

Hardware and Software Details

Scanning Speed 2400 dpi, draft mode: Color 16.0 msec/line; Grayscale 5.3 msec/lineLight Source Xenon gas cold cathode fluorescent lampInterface Hi-Speed USB 2.0, FireWire® (IEEE 1394)Reliability MCBF - 100,000 cyclesMaximum Read Area 12.2" x 17.2" (310mm x 437mm)

SpecificationsScanner Type Flatbed color image scannerPhotoelectric Device Color Epson MatrixCCD™ line sensorOptical Resolution 2400 dpiHardware Resolution 2400 x 4800 dpi with Micro Step Drive™ technologyMaximum Resolution 12,800 x 12,800 dpi with software interpolationEffective Pixels 87,840 pixels/line (2400 dpi)Color Hardware Bit Depth 48-bits per pixel internal, 48-bits per pixel external (External bit depth is selectable to 48 bits depending on the image editing software.)Grayscale Hardware Bit Depth 16-bits per pixel internal, 16-bits per pixel external (External bit depth is selectable to 16 bits depending on the image editing software.)Optical Density 3.8 Dmax broad dynamic range Focus Control AutoFocus optics system (CCD and lens unit)

Process of scanning

24b color image by resolution 800dpi in JPG format (preview)

16b Grayscale image by resolution 1600dpi in FITS format (~18 min of scanning, original)

500 plates 30х30cm, more than 300GB

http://www.skyarchive.org/

Thank you for attention!

Acknowledgments:

This work is possible due to the National Scientific Foundation under Grants NIK-05, DO-02-273 and DOES 02-85.