Numbers…

1. Digitization and Archivingof thePalomar-Leiden Survey of Faint Minor Planetsand theThree Palomar-Leiden Trojan Surveys L. D. Schmadel1, G. Burkhardt1, R. M. Stoss1, W. Paech21Astronomisches Rechen-Institut, Heidelberg, Germany 2Institut 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. 1960 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)

4. 1971 First Palomar-Leiden Trojan Survey (T1S) • 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)

5. 1973 Second Palomar-Leiden Trojan Survey (T2S) • 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)

6. 1977 Third Palomar-Leiden Trojan Survey (T3S) • 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)

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

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

9. N * S EW 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

10. A3 flatbed color image scanner • Epson MatrixCCDTM 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) Epson 10000XL

11. FEM analysis of plate bending

12. Projectstages • 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) Direction of scanning Global distortions

24. Solver 10min exposure 40min exposure

25. GetField

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