The Palomar - Leiden Survey ( PLS also short ) is a large-scale sky survey, which was conducted from 1960 to 1977 for the targeted search for small planets. " Palomar - Leiden " is an extension of McDonald Asteroid Survey ( MDS) by Gerard Peter Kuiper 1952, and comparable to the Palomar Sky Survey, but enough with 20.5 may not quite reach the limiting magnitude approach.
Intitiatoren of the project were mainly Kuiper, Paul Herget, Tom Gehrels and Cornelis Johannes van Houten, Ingrid van Houten and his wife - Groeneveld. It served - as well as the three Trojan Surveys - as a basis for studies of statistical and dynamic properties of the main asteroid belt between the orbits of Mars and Jupiter.
For Palomar - Leiden Survey were in 1960 a total of 100 field plates ( plate size 35.6 x 35.6 cm, 1 mm thick) taken with the large Schmidt telescope at Mount Palomar Observatory. Among the 100 field plates for a further 30 individual plates of gauge fields came to the photometry of the field plates. Exposure time was about 10 minutes ( for blue-sensitive photographic plates ) and 40 minutes ( yellow plates), the sky section shown is 6.5 x 6.5 degrees in size. The covered area of sky of the PLS was 12 x 18 degrees and was in a total of eight individual fields of 6.5 ° divided.
Given the scope of the surveys, the project was divided into three institutes: the Lunar and Planetary Laboratory in Tucson, the Cincinnati Observatory (then seat of the Minor Planet Center ), and the suffering Observatory in Holland. The Lunar and Planetary Laboratory ( Gehrels ) was responsible for the creation of shots, Leiden ( I. van Houten - Groeneveld and CJ van Houten ) for the measurement of the plates and the Cincinnati Observatory ( Herget ) ultimately for the calculation of the orbital parameters of the newly found minor planets.
On the Palomar - Leiden plates over 2,000 new minor planets were discovered, of which 14,000 positions and 7,500 were measured from reference stars. To this day, " Palomar - Leiden " is used for orbit determination of asteroids.
Since the spring of 2005, the Astronomical computing Institute (ARI ) is cooperating in Heidelberg under the direction of Lutz D. Schmadel with the Erdmessungs Institute of the Technical University of Hanover for archiving and digitization of the Palomar - Leiden Survey and the Trojan survey, which was at that time carried out for similar purposes.