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

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

Palomar-Leiden Survey (PLS) -Statistical studies of asteroid population (Extension to MDS [ , lim. mag. 16]) -18° x 12° region centered on vernal equinox  3x2 fields -130 plates 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

-Statistical studies of Jupiter-Trojan population -12° x 12° region  2x2 fields centered on L5 -54 plates 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)

-Statistical studies of Jupiter- Trojan population -12° x 12° region  2x2 fields centered on L4 -76 plates 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)

-Statistical studies of Jupiter-Trojan population at L5 -6° x 30° region  1x5 fields centered on L5 -68 plates 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)

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

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

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

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)

FEM analysis of plate bending

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

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

P-L plate detail as seen from the glass side

Documentation: image processing

Wobbling (Scan direction horizontal)

Wobbling (Scan direction vertical)

25 x 17 crosses out of 116 x 116 matrix

Clean cross and contaminated cross

Wobbler…, 1µm positional, 0.1 pixel accuracy

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

Solver 10min exposure40min exposure

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