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Dr. Renate Budell

Photometric Accuracy of Flatbed Scanners Compared to PDS Microdensitometers. Dr. Renate Budell. Institut of Astronomy, Bulgarian Academie of Sciences. Physikalisches Institut, Westfälische Wilhelms-Universität Münster. e-mail: budell@wwu.de. Scanners. Epson V700. PDS 2020 GM.

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Dr. Renate Budell

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  1. Photometric Accuracy of Flatbed Scanners Compared to PDS Microdensitometers Dr. Renate Budell Institut of Astronomy, Bulgarian Academie of Sciences Physikalisches Institut, Westfälische Wilhelms-Universität Münster e-mail: budell@wwu.de

  2. Scanners Epson V700 PDS 2020 GM

  3. Parameters of the scanners tested Epson V700 PDS Maximum Density D=5.2 D~3 Resolution > 12 μm >= 5 μm Depth of Focus ~ 1 mm some μm Scanning Speed fast slow

  4. Transmission and Density I T= I0 1 D=lg T

  5. Scanning of the negative

  6. VueScan • VueScan is an alternative to the usual scan programmes delivered with the scanners. • With VueScan one can get unprocessed data (raw mode) • VueScan is a program, not a driver. It is not possible to use it together with FitsScan. • Output in raw mode is possible in Tiff format only.

  7. Interobservatory Calibration WedgeSet 38, No. 3, IIIaJ

  8. Inter Observatory Calibration Wedge Set 38, No.3, IIIaJ

  9. Stray Light at Flatbed Scanners

  10. Gray-wedge without Silver-grain

  11. MTO Gray-wedge (grainless)

  12. Characteristic Curves of Kodak IIIaJ

  13. Characteristic Curves of Kodak IIaO

  14. CCD-Line

  15. Color to Gray

  16. Infrared - Blue

  17. Conclusions • Photometrie with Flatbedscanners goes wrong while scanning photo plates with silver grains. If density is higher, the error of photometrie is bigger. • PDS Microdensitometers should be kept working when scanning in high presition.

  18. Recommendations • Investigations in astrometric accuracy using scans of flatbed scanners should continue. • Investigations how to use flatbed scanners on spectral plates must be done.

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