1. Digitization and Archiving of the Palomar-Leiden Survey of Faint Minor Planets and the Three Palomar-Leiden Trojan Surveys L. D. Schmadel 1, G. Burkhardt 1, R. M. Stoss 1, W. Paech 2 1 Astronomisches Rechen-Institut, Heidelberg, Germany 2 Institut für Erdmessung, Hannover, Germany

2. Numbers… -1.2-m f/2.5 Oschin Schmidt on Palomar Mountain -Kodak Glass Plates, 35.6cm x 35.6cm, 1mm thickness -Field of View: 6.5° x 6.5° -Limiting magnitude: ~ 20mag

3. Palomar-Leiden Survey (PLS) -Statistical studies of asteroid population (Extension to MDS [1950-52, lim. mag. 16]) -18° x 12° region centered on vernal equinox  3x2 fields -130 plates -1960 Sept. 24, 25, 26, 27, 28, 29, and Oct. 17, 22, 24, 25, 26 -Exposure times of 10min to 40min -Guided on mean asteroid motion! Total of ~ 2400 discoveries 1561 numbered (MPC, 2006 Apr. 16) 1960

4. -Statistical studies of Jupiter-Trojan population -12° x 12° region  2x2 fields centered on L5 -54 plates -1971 Mar. 24, 25, 26, 27, and Apr. 02, 16, and Mai 13, 14, 16 -Exposure times of 12min -Guided on mean Jupiter-Trojan motion! Total of ~ 750 discoveries 429 numbered (MPC, 2006 Apr. 16) 1971 First Palomar-Leiden Trojan Survey (T1S)

5. -Statistical studies of Jupiter- Trojan population -12° x 12° region  2x2 fields centered on L4 -76 plates -1973 Sept. 19, 20, 24, 25, 29, 30, and Oct. 04, 05 -Exposure times of 12min -Guided on mean Jupiter-Trojan motion! Total of ~ 1400 discoveries 1008 numbered (MPC, 2006 Apr. 16) 1973 Second Palomar-Leiden Trojan Survey (T2S)

6. -Statistical studies of Jupiter-Trojan population at L5 -6° x 30° region  1x5 fields centered on L5 -68 plates -1977 Oct. 07, 11, 12, 16, 17, 21, 22 -Exposure times of 9min to 13min -Guided on mean Jupiter-Trojan motion! Total of ~ 1500 discoveries 855 numbered (MPC, 2006 Apr. 16) 1977 Third Palomar-Leiden Trojan Survey (T3S)

7. The authors of THE PALOMAR-LEIDEN SURVEY OF FAINT MINOR PLANETS Astron. Astrophys. Suppl., 2, 339-448 (1970) Tom Gehrels (b.1925) Paul Herget (b.1908, †1981) Ingrid van Houten-Groeneveld (b.1921) Cornelis Johannes van Houten (b.1920, †2002)

8. Palomar Observatory 1.2-m Schmidt MPC in Cincinnati (1947-1978) Leiden Observatory MPC in Cambridge (1978- )

9. A problem and a solution… -Total of ~ 340 plates -Each one 35.6cm x 35.6cm in size (14“ x 14“) -Largest affordable Scanner (DINA3: 29,7cm x 42,0cm): ~ 12“ x 17“  Problem!  Solution… -Two Scans per plate -1800dpi  0.95“/pixel -Each Scan = 0.8 GB -Total of 0.5 TB N *SN *S E W

10. Epson 10000XL A3 flatbed color image scanner Epson MatrixCCD TM line sensor Read area 12.2"x 17.2" (310mm x 437 mm) 87,840 pixels/line (2400 dpi optical resolution) Scanning speed 5.3 msec/line (grayscale) Grayscale depth 16-bit/pixel, Dmax 3.8 AutoFocus system (CCD and lens unit)

11. FEM analysis of plate bending

12. Project stages Phase 1 - Plate shipping from Leiden to Hannover Phase 2 - Photographic documentation Phase 3 - Cleaning Phase 4 - Scanning Phase 5 - Software development Phase 6 - Scanner analysis Phase 7 - Archive generation Phase 8 - Plate shipping from Hannover to Heidelberg Phase 9 - Scientific data mining tasks + Archive Online

14. Palomar Schmidt plate label at the NE corner (emulsion side: plate number, date, center coordinates)

15. P-L plate detail as seen from the glass side

16. Documentation: image processing

18. Wobbling (Scan direction horizontal)

19. Wobbling (Scan direction vertical)

20. 25 x 17 crosses out of 116 x 116 matrix

21. Clean cross and contaminated cross

22. Wobbler…, 1µm positional, 0.1 pixel accuracy

23. Fourieranalysis in direction of Scanning (local distortions) Global distortions Direction of scanning

24. Solver 10min exposure40min exposure

25. GetField

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