RARE "Dutch Astronomer" Peter van de Kamp Signed 4X6 Card For Sale

Up for sale a RARE! "Dutch Astronomer" Peter van de Kamp Hand Signed 4X6 Card.

ES-4168E

Piet van de Kamp (December

26, 1901 in Kampen – May 18, 1995 in Amsterdam), known as Peter van de Kamp in the

United States, was a Dutch astronomer who lived in the United States most of his

life. He was professor of astronomy at Swarthmore College and

director of the college's Sproul Observatory from

1937 until 1972. He specialized in astrometry, studying parallax and proper motions of stars. He came to public attention in

the 1960s when he announced that Barnard's star had a planetary system based on observed

"wobbles" in of its motion, but this is now known to be false. On

November 14, 2018 the Red Dots project

announced that Barnard's star hosts

an exoplanet at least 3.2 times as massive as Earth. Van de Kamp was the son of

Lubbertus van de Kamp, who had an administrative job at a cigar factory, and

Engelina C.A. van der Wal. His younger brother Jacob van de Kamp was also a

successful scientist: an organic chemist, who spent most of his career in the

United States.[5] Van de Kamp studied at the University of Utrecht and

started his professional career at the Kapteyn Astronomical Institute in Groningen working with Pieter Johannes van Rhijn.

In 1923 he left for the Leander McCormick Observatory at

the University of Virginia for

a year's residence supported by the Draper Fund of the National Academy

of Sciences. There he assisted Samuel Alfred Mitchell with

his extensive stellar parallax program and Harold Alden with the lengthy Boss star project. The following year Van de Kamp went to

the Lick Observatory in

California as a Kellogg fellow. There he received his PhD from the University of California in

Astronomy in June 1925. The next year he also received a PhD from the University of Groningen.[1] Van de Kamp returned to McCormick on

October 1, 1925 to take up the position left vacant by Harold Alden, who had just taken up the directorship of

the Yale University Observatory Southern

Station in Johannesburg, South Africa. His work

consisted of assisting with the parallax program and continuing the proper

motion work that he and Alden had begun. Van de Kamp and Alexander N. Vyssotsky spent

eight years measuring 18,000 proper motions. He did additional, smaller

projects individually, including an investigation for general and

selective absorption of light within

the Milky Way. In the spring of 1937, Van de Kamp left McCormick

Observatory to take over as director of Swarthmore College's Sproul Observatory. There

he Star and in the 1960s reported a periodic

"wobble" in its motion, apparently due to planetary companions. It was not until several decades had

passed that a consensus had formed that this had been a spurious detection. In 1973 astronomers George Gatewood of the Allegheny the University of Florida,

using data obtained with improved equipment on the 30-inch Thaw Refractor

telescope, did not detect any planets but instead detected a change in the

color-dependent image scale of the images obtained from the 24-inch refractor

telescope at the Sproul Observatory used

by Van de Kamp in his study.[10] Astronomer John L. Hershey found

that this anomaly apparently occurred after each time the objective lens was removed, cleaned, and replaced.

Hundreds more stars showed "wobbles" like Barnard's Star's when photographs before and after cleaning

were compared – a virtual impossibility. Wulff Heintz, Van de Kamp's successor at Swarthmore and an

expert on double stars, questioned his findings and

began publishing criticisms from 1976 onwards; the two are reported to have

become estranged because of this. Van de Kamp never admitted that his

claim was in error and continued to publish papers about a planetary system

around Barnard's Star into

the 1980s, while modern radial velocity curves place a limit on the

planets much smaller than claimed by Van de Kamp Recent evidence suggests

that there is, indeed, a planet orbiting Barnard's Star, albeit of much lower

mass than Van de Kamp could have detected.

From

the 1940s on Van de Kamp and his staff made similar claims of planetary systems

around the nearby stars Lalande 21185, 61 Cygni, and many others, based on the same flawed

photographic plates. All of these claims have been refuted. However,

with the recent discoveries of numerous planetary systems, the idea that

planetary systems are common—of which throughout his life Van de Kamp was a

strong promoter—is being gradually proven correct.