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Homepage of Piet van der Kruit

Prof. dr P.C. van der Kruit
Jacobus C. Kapteyn Distinguished Professor of Astronomy
Kapteyn Astronomical Institute
P.O. Box 800, 9700 AV Groningen, the Netherlands
Tel.: +31 50 363 4062 / 4073 ; Fax:+31 50 363 6100
Hertenlaan 65, 9408 CH Assen, the Netherlands
Tel.: +31 592 857 757

Contents of this homepage

Astronomical Images

Hubble Heritage Gallery CFHT Hawaiian Starlight Astronomy Picture of the Day
See also image galleries at: ESO, HST, JPL, SDSS, RC3 and NOAO.

For the latest news see Universe Today

My c.v. and publication list and my academic genealogy.
Kapteyn Astronomical Institute and Jacobus C. Kapteyn
Challenges symposium
Sun, Moon, planets, sky and time
Publications and presentations

Scientific publications
Inaugural and valedictory lectures
Stellar Populations Symposium
Kapteyn Legacy Symposium
Presentations of scientific talks
Citation analysis
General articles
Publieke lezingen/Popular lectures
J.H. van Oosbreelezing
ESO Council
Vijf Jaar voor Beta's
Lecture courses
Inleiding sterrenkunde
Structure of galaxies
Kosmische evolutie
Dynamics of galaxies
Sterren( en melkweg)stelsels
Structure and dynamics of galaxies
Minor Planet 10437 van der Kruit (6085 P-L)
Distinguished professorship
Royal Decoration
In the air
Koninklijk Natuurkundig Genootschap
Earth at night
Powers of Ten
Astronomical and Related Services and Literature
NGC 891

Kapteyn Astronomical Institute and Jacobus C. Kapteyn

The Kapteyn Astronomical Institute is part of the Faculty of Mathematics and Natural Sciences of the University of Groningen in the Netherlands.
It is also part of the Netherlands Research School for Astronomy (NOVA)

The Kapteyn Astronomical Institute as well as my honorary chair are named after the Institute's founder, Professor Jacobus Cornelius Kapteyn, who lived from 1851 to 1922. Below I refer to a "Legacy Symposium" about Kapteyn that Klaas van Berkel and I organised in 1999. Here is a photograph of the painting of Kapteyn by Jan Veth, made in 1918 at the occasion of his 40th anniversary as professor at Groningen University. It resides in the Kapteyn Room at the Kapteyn Astronomical Institute.

I have written a short article about Kapteyn (Jacobus Cornelius Kapteyn) in the "Academische Boekengids" (in Dutch). Here is an English version. Kapteyn also features prominently in my `valedictory' lecture `It all started with Kapteyn' (here is a version for `booklet'-printing).

I am maintaining a dedicated website about Jacobus Cornelius Kapteyn.

The Kapteyn Astronomical Institute is located on the Zernike Complex. Here is a rather old and a new (but already out of date) picture of the complex and a more recent one of the Institute. You can find here a map of the Zernike Complex, an indication of the location with respect to Groningen and directions how to get to the Zernike Campus and the location of the Institute there.

The main building of the University of Groningen is located in the town center. The various locations of the University can be seen in this set of aerial photographs.

I have some time ago written a brief history of the Kapteyn Astronomical Institute.
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Click for a map of the Netherlands , or for a satellite picture of the Netherlands.

This is the house, (Vredewoldlaan 62, Groningen), where we lived between 2002 and 2008. According to the Actueel Hoogtebestand Nederland the location is 0.7 meters below sea level.

Since April 2008, we live at Hertenlaan 65, Assen. This is the front and the back. According to the Actueel Hoogtebestand Nederland this location is 11.6 meters above sea level. The geographical coordinates are: Longitude East 6 degrees 31.1 minutes, Latitude North 52 degrees 59.9 minutes.

Here is a view of our house from Google Maps.

You can use Google Maps for a larger view or for directions how to reach our home.

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Challenges symposium

At the occasion of my 65-th birthday the Kapteyn Astronomical Institute and the Koninklijk Natuurkundig Genootschap (Royal Natural Sciences Society) organized a one-day symposium for a broad audience with the title Challenges. This was held on October 12, 2009. The symposium ended with my valedictory lecture.
At that occasion the Faculty of Mathematics and Natural Sciences presented me with a formal academic painting of me to be donated to the University of Groningen. It now resides in our Faculty Room in the central University building as part of the University's collection of portraits (see here for the catalogue listing of mine).
I was also presented with a set of photo's of the symposium, reception and dinner.

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Click for Eelde, Netherlands Forecast Click for 
Eelde, Netherlands Forecasst

Below are a few sites with interesting information on the weather, concerning both the current situation and archives. Most are in Dutch. Click here for more detailed information on the meteorological conditions in the Netherlands; also available is the site of the official Dutch meteorological service KNMI, which has the current weather and related information. Other excellent Dutch sites with much information are and For information in English click here.

Click for the weather forecast for Groningen from the World Meteorological Organization or the Weather Channel or for the Netherlands from the Microsoft Network MSN. You can find here also a radar map of rain in the Netherlands.

Here are weather statistics for the Netherlands for the current month and the archival data.

The part of the Netherlands, where I live, has the following weather characteristics: The monthly averaged minimum temperature varies from -0.1 C in February to 12.5 C in July and the monthly averaged maximum temperature from 5.1 C in January to 21.9 C in August. There are on average 4 days per year when the temperature gets above 30 C and 8 when the temperature does not get above 0 C. The sun shines 1602 hours per year, which is 36.6% of the available time. There are per year on average 80 days without any sunshine and 29 when the sun shines for more than 80% of the available time. The annual precipitation is 883 mm and the total duration is 667 hours, which is 7.6% of the time. There are on average 165 days per year without any precipitation and 136 with 1 mm or more. All of this of course is quite typical for northern Europe.

The current sea and land temperatures and cloud cover are (if it does not update click it)

There is also a movie of these images over the last week or so.

Worldwide highest temperatures for today can be found here .

The temperatures in Europe over the last 24 hours are shown in the following animation (if it does not show click the little square; if it does not update click the frame)

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Sun, Moon, planets, sky and time

Click for Eelde, Netherlands Forecast

Here are some useful links with astronomical information:

Today's position, times of rising and setting for the Sun, and times of twilight, etc. in the Netherlands, and an advanced calculator.
Today's position of the Moon on the sky, its phase and additional information. Here is a listing of Moon phases.
The data for the planets and a current map of the Solar System.
Information in Dutch on observable occurences on the sky over the next few weeks are listed on the site of Govert Schilling. A comprehensive site in English is that of Sea & Sky.
The sky at this time as seen from Amsterdam.
The Mag-7 Star Atlas Project of Cloudy Nights provides beautiful atlas of the sky.
The Website of the U.S. Naval Observatory can be consulted for all kinds of astronomical information, including rising and setting of Sun and Moon, twilights, moonphases, eclipses and transits, and much more.
Fred Espenak at JPL maintains a nice site with information on past and future solar and lunar eclipses.
A very useful site with much information on time, weather, sunrise, sunset, etc. is time and date. You can find there the current time for most countries and their capitals; this site also has calenders for different countries and years. Accurate clocks are available that show the current Greenwich Mean Time from the UK and Universal Time from the USA. You should not be able to detect any difference. Another useful site is calendar-365.
Click on the picture for an up-to-date day/night picture of the Earth (and many related interesting features)

This day/night picture applies to the equinox at local mean solar time 12:00 at Groningen (longitude 6.550 degrees East; latitude 53.217 degrees North). Here you can see the pictures at the (northern hemisphere) summer and winter solstices.
The civil time in the Netherlands is Central European, corresponding to the meridian of 15 degrees East. The longitude correction for Groningen with respect to that meridian is +33.8 minutes. In the spring (20 March) the Equation of Time is -7.3 minutes (of time), so noon in local mean solar time corresponds to 12:26:30 Central European Standard Time or 11:26:30 Universal Time (UTC). In the fall (22 September) the Equation of Time is +7.4 minutes, so the corresponding times are 13:41:12 Central European Daylight-saving Time and 11:41:12 UTC. The equation of time is one aspect that determines the form of the analemma.

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Publications and presentations

Scientific publications

It is possible to get a list of my papers that are present on the preprint server Astro-ph.

The NASA Astrophysics Data System (ADS) maintains an electronic list of essentially all astronomical literature. It provides for recently published papers links to electronic versions of the scientific journals, but you need an electronic subscriptions to access these papers. Papers and reviews in journals and contributions to many proceedings published before 1999 (or so) have all been scanned and are available through ADS and are available without charge. The ADS can select and order publications in various ways, but not always correctly. In particular book reviews, errata and unrefereed contributions to conference proceedings are added to such lists when they appear in refereed journals. Below are links to my papers, ordered and selected in various ways.
papers ordered by year of publication.
Refereed papers ordered by the number of citations received.
Non-refereed papers ordered by year of publication.
All papers ordered by number of citations.

My papers since 1999, that are not available in scanned versions through ADS, can be obtained in pdf-format directly here. Papers before 1999 that are not available through ADS can be found there as well.
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Inaugural and valedictory lectures

For those who read Dutch there is a copy of my "inaugural lecture" at the University of Groningen at the occasion of my appointment as full professor per June 1, 1987, entitled `Welke ster is nu de mijne?' and delivered on Januari 26, 1988.,
My "valedictory lecture" at the University of Groningen was delivered on October 12, 2009 at the end of the symposium Challenges, held at the occasion of my retirement. It is partly in English, partly in Dutch and has the title `It all started with Kapteyn'. There is also a booklet version.
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Stellar Populations Symposium

The proceedings of IAU Symposium 164 on ``Stellar Populations'' (1994), edited by P.C. van der Kruit and G. Gilmore, have been reprinted and revised in Volume 267 of Astrophysics and Space Science (2000). Here is the preface.
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Kapteyn Legacy Symposium

The Legacy of J.C. Kapteyn: Studies on Kapteyn and the Development of Modern Astronomy, edited by P.C. van der Kruit and K. van Berkel. This are the proceedings of a symposium organized by Klaas van Berkel and myself at the occasion of the 385th anniversary of the University of Groningen in 1999.

Here are the title page, contents and preface .
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Selected presentations of scientific talks

Structure and dynamics of disks , invited review at ``The Dynamics, Structure & History of Galaxies'', a workshop at the occasion of Ken Freeman's 60-th birthday, Dunk Island, Queensland, Australia, July/August 2001.
The stars and gas in outer parts of galaxy disks - Extended or truncated, flat or warped? , invited review at ``Formation and Evolution of Galaxy Disks'', Vatican Symposium, Rome, Italy, October 2007.
The masses of disks , invited review at ``Unveiling the Mass'', in honor of Vera Rubin's 80th birthday; Kingston, Canada, June 2009.
Structure, mass and stability of galactic disks , invited review at ``Galaxies and their Masks'', in honor of Ken Freeman's 70th birthday; Sossusvlei, Namibia, April 2010.
Truncations in stellar disks and warps in the HI layers in spiral galaxies , colloquium given at a number of places, most recently (Sept/Oct 2011) at the National Astronomical Observatory of China in Beijing and the Shanghai Astronomical Observatory in Shanghai, China.
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Citation analysis

A comparison of astronomy in fifteen member countries of the Organisation for Economic Co-operation and Development
P.C. van der Kruit, Scientometrics 31, 155-172 (1994).
The astronomical community in the Netherlands
P.C. van der Kruit, Quarterly Journal of the Royal Astronomical Society 35, 409-423 (1995).
Citation analysis and the NASA Astrophysics Data System (ADS)
P.C. van der Kruit (2005).
Citations and impact of Dutch astronomy
P. Kamphuis and P.C. van der Kruit (2010).
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General articles
The following are in English:
The Recruitement to Science and Engineering Courses in the Netherlands (1997)
Man's Place in the Universe (1994)
Ranking of national soccer teams (1998)
Safety in transport and traffic (2001). This a response to a column by Karel Knip in the national newspaper NRC/Handelsblad. Hier zijn (in Dutch) de oorsponkelijke column, mijn respons and Knip's reactie in een latere column.
Home advantage and tied games in soccer (2006)

The following are in Dutch:
Astronoom van beroep (oorspronkelijk gepubliceerd in 1987 in `Zenit')
Harmonie (1993)
Jacobus Cornelius Kapteyn Academische Boekengids (1999)
Sturing van Wetenschappelijk Onderzoek (1998)
Tijd (2001)
Stonehenge (2001)
Kan de mens niet 100, maar 100.000 jaar overleven?, bespreking van Surviving 1000 centuries: can we do it?, van Roger Bonnet & Lodewijk Woltjer voor de Academische Boekengids (2009)
Dan zouden we het toch gehoord hebben?, bespreking van zes boeken over intelligent leven in het heelal en exoplaneten voor de Academische Boekengids (2010)
Radioruis en de kosmos, bespreking van drie boeken over de geschiedenis van de radiosterrenkunde, kosmologie en kosmische achtergrondstraling voor de Academische Boekengids (2011)
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Publieke lezingen/Popular lectures

In het Nederlands:
De witte netten van zon en maan (2001).
Neem nou het heelal (2007).
De Ster van Bethlehem: Mogelijke astronomische verklaringen (2011).
In English:
The Star of Bethlehem (1993).
2009: the International Year of Astronomy. Lecture held for the Koninklijk Natuurkundig Genootschap, January, 2009.
Intelligent Life in the Universe: Crowded skies, lonely planet or rare Earth?. Lecture held for the Koninklijk Natuurkundig Genootschap on November 15, 2011.
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J.H. van Oosbreelezing

In 2008 ben ik uitgenodigd de tiende J.H. van Oosbreelezing te houden. De lezing is gehouden op 5 april te Amersfoort onder de titel "OORSPRONG: Over mens en heelal, wetenschap en religie, samenhang en toeval, de weg en de herberg".
Hier zijn respectievelijk
De omslag van het boekje, uitgegeven door Eburon.
De beamer presentatie.
Een uitgebreide (XXL) versie van het boekje (ook beschikbaar in `booklet-printing' format met grotere letter; print dubbelzijdig op A4 met optie duplex=short edge en snij middendoor).
Tijdens de lezing vertoonde ik de film Cosmic Voyage, waarvan delen te zien zijn op het Web.
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ESO Council

Between summer 2000 and end of 2005 I was Netherlands delegate and later President of the Council of the European Southern Observatory with an extra year in 2006-2007. I have written down my experiences in Five-and-a-half years in ESO Council. This is a text written for a public that does know little about the European telescopes in Chile.
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Vijf Jaar voor Beta's

De noodzaak van een vijfjarig curriculum voor de beta-opleidingen aan de algemene universiteiten.
Rapport van de Commissie Vijfde Jaar Beta Studies (juni 1997), waarvan ik voorzitter was, op grond waarvan de minister uiteindelijk een vijf-jarig curriculum heeft goedgekeurd.
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Lecture courses

Inleiding Sterrenkunde
This is an introductory course on astronomy that I gave to first year students in Dutch in the years 1975-1982, 1984-1991 and 1998-2002. It developed in the course of time and here are the viewgraphs (in Dutch) of the course in the final year 2002.
Transparanten van de colleges:

1. Positionele sterrenkunde; aardafplatting
2. Het planetenstelsel; twee-lichamen probleem
3. Helderheid, temperatuur, classificatie en massa van sterren; Hertzsprung-Russell diagram
4. Vorming van sterren
5. Evolutie van sterren
6. Eindstadia van sterren
7. Afstandsbepaling en interstellaire materie
8. Structuur en dynamica van ons Melkwegstelsel
9. Melkwegstelsels
10. Kosmologie
11. Waarom is het 's nachts donker?

Het boek bij het college (bruikbaar als achtergrond materiaal; niet voor definitie of tentamenstof) is

De tentamenstof is gedefinieerd aan de hand van de transparanten en deze tekst . Tentamenstof en antwoorden van 26 juni 2000, 2 juli 2001 en 1 juli 2002.
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Structure of Galaxies (Structuur van melkwegstelsels).
This course evolved from an introductory course on galaxies that I first set up in the late seventies together with Ron Allen and Ron Ekers and which I have given by myself since about 1980 until 2002 mostly in a two-year cycle. It has also been the basis of my part of the Saas-fee course "The Milky Way as a Galaxy", that I gave in 1989 together with Ivan King and Gerry Gilmore. I have given the course also at a number of occasions as one-week lecture series: twice as part of the NOVA fall-school, once for students from Bochum University, at the University of Porto, Portugal (this year for the fourth time) and once at ESO-Vitacura in Santiago, Chile.

To the written documentation with the course belong this background document with references, definition of the material for the exam and two exersizes, plus additional background papers summarizing the theories of Galactic Dynamics and Chemical Evolution. (Versions with larger characters for booklet printing are here and here.)
In earlier times the exam consisted partly of presentations by students discussing recent professional publications on related research and for this I prepared a set of Hints on presenting papers. This is from the early nineties, when presentations were done using overhead projectors, so much is out of date.

The viewgraphs of this course were in English. These were available as .pdf files and the full set of the lectures up to 2006 are available as a single zipped tar-file here.

The course was revised and updated in early 2007 for the series of lectures in Santiago and Porto and changed into beamer presentations. The most recent individual chapters are:

1. Structure, kinematics and dynamics of the Galaxy
2. Stellar Populations, classification, surface photometry
3. Luminosity distributions and component analysis
4. Photometric parameters and evolution
5. Kinematics of galaxies
6. Dynamics of galaxies
7. Structure of galaxy disks
8. Absorption, chemical evolution
9. Elliptical galaxies
10. Formation of galaxies

The course uses the textbooks (useful to have as background material):

My chapters in "The Milky Way as a Galaxy" are available as .pdf files in a different lay-out then the original publication:
Ch. 5: Photometric components in disk galaxies
Ch. 10: Kinematics and mass distributions in spiral galaxies
Ch. 12: The distribution of properties of galaxies
Ch. 14: Chemical evolution and disk galaxy formation
Ch. 15: The Milky Way in relation to other galaxies

Hier zijn de tentamen opgaven van 12 maart 1999, 19 maart 2001 en 2 december 2002 .
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Enige jaren heb ik in het college Evolutie van Prof. van Delden aan biologen twee colleges gegeven over Kosmische evolutie. De bijbehorende transparanten zijn hier te vinden. In het nieuwe onderwijsprogramma is daar helaas geen plaats meer voor.
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Dynamics of galaxies
The course follows in broad terms the document Galactic Dynamics (version for booklet printing) that I used in connection with my course on "Structure of galaxies", but expands on it in specific cases. Further supporting material concerns the two-body problem and the restricted three-body problem.
I gave this course first in the academic year 2006-2007. As part of this Bob Sanders lectured for two weeks on barred galaxies. There was a written exam.
I gave the course again in 2008-2009, now with Amina Helmi lecturing for two weeks on a satellite orbiting in a spherical potential. The presentations for my lectures are:
1. Fundamentals
2. Timescales and stellar orbits
3. Motions, instabilities and the velocity ellipsoid
4. The self-consistency problem and potential theory
5. Observations of distributions
6. Observations of kinematics
7. Dynamics of spiral galaxies
8. Dynamics of elliptical galaxies

The course uses for reference to background material the textbook (preferably the second edition):

Sterren( en melkweg)stelsels
This a lecture course (in Dutch) on "stars and galaxies" for first-year students that I gave for the first time in 2007 and for the last time in 2009. It is also known as the course "Sterrenstelsels" and for the most part follows my original course Introductory Astronomy.
Here are pdf-files of the lecture presentations:

1. Eigenschappen van sterren: Hertzsprung--Russell diagram
2. Interstellar medium en stervorming
3. Sterevolutie en afstandbepaling
4. Eindstadia van sterren
5. Structuur en dynamica van ons Melkwegstelsel
6. Melkwegstelsels
7. Kosmologie

Het boek bij het college is voor raadpleging:

De tentamenstof is gedefinieerd aan de hand van bovenstaande presentaties en is dat wat behandeld is op college.

Structure and dynamics of galaxies
This is a 24-lecture course I gave in September 2011 for Master and graduate students at the Graduate University of the Chinese Academy of Science and of Peking University in Beijing, China. It is a merger of the two advanced lecture courses above, but somewhat updated.
The presentations can be downloaded as one large pdf-file (26.9 Mb) or for each lecture separately. In the latter case you download the first lecture and then replace `Beijing01.pdf' in the URL with `Beijingnn.pdf' with nn from 02 to 24.

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Minor Planet 10437 van der Kruit (6085 P-L)

On July 5, 2001 the International Astronomical Union announced that it has named minor planet (or asteroid) 6085P-L after me. The orbital elements of 10437 van der Kruit are a semi-major axis of 2.3690 Astronomical Units (1 A.U. is about 150,000,000 km), an excentricity of 0.2248 and an inclination of 1.779 degrees. The orbital period around the Sun is then 3.65 years. The closest it will get to the Earth is about 125 million kilometers. Upcoming near approaches are September 4, 2011 (0.868 AU or 130 million km), July 12, 2029 (0.882 AU or 132 million km) and July 24, 2040 (0.838 AU or 126 million km). The diameter is unknown, but judging from its brightness it should be about 5 km or so.

Here is the orbit and the position on two dates roughly half a year apart.

These pictures have been produced using . This site is set up for so-called Near-Earth Objects (NEO's), which are minor planets that in their orbits may come very close to Earth. The orbits are bright lines when above that of the Earth and darker when below. The planets and minor planet move in this representation clockwise. The slanted yellow line shows the directions of the equinoxes.
The current position on the sky with respect to the stars and constellations can be found using Your Sky.

The orbit of the Earth (and the planets, minor planetss and comets) is elliptical. The aphelion (point furthest from the Sun) is about 4% further from the Sun than the perihelion (closest point). The Earth is in perihelion early January (usually between 2 and 5 January) and in aphelion early July (usually between 3 and 7 July). The equinoxes (when day and night are equal) are on 20 or 21 March and on 22 or 23 September and the solstices (when day or night are longest) on 20 or 21 June and on 21 or 22 December. A listing of ap- and perihelion passages, equinoxes and solstices between 1992 and 2020 can be found at the U.S. Naval Observatory. The distances in the Solar System are in Astronomical Units (AU), which is the mean distance between the Earth and the Sun; it is about 150 million km or about 8.3 lightminutes.

The site above at JPL can also be used to view where comets are in their orbits. Here is a recent position of Comet Halley in projections face-on and edge-on to the Earth's orbit. In the face-on view the comet moves anti-clockwise (retrograde with respect to the planets, that move clockwise).

Minor planetss are large number of small bodies moving between the orbits of Mars and Jupiter. The largest (discovered on the first day of the 19-th century: January 1, 1801) has Ceres, which is a spherical body with a radius of about 475 km.

In very recent times a number of large bodies have been discovered in the outer Solar System in the so-called Kuiper Belt. Some of these are comparable in size to the Pluto (diameter 2320 km). One (Eris) is even larger than Pluto (see the story of the discoverer Mike Brown). Including Pluto and its moon Charon, there are now at least 11 objects with diameters definitely or possibly larger than 1000 km. It is fun to use the JPL/NEO site to look at their orbits. Some designations (or names when the IAU has assigned these) are Eris, Haumea, Makemake, Sedna, Orcus, Quaoar, Ixion, 2002 AW197 and Varena.

During the 2006 General Assembly of the International Astronomical Union in Prague the astronomical definition of a planet has been adopted. The Website of the I.A.U. gives more details. I have voted for Resolution 5, since Pluto is definitely a different kind of object than the other eight (major) planets, and I have voted against Resolution 6, sincs I felt it was unnecessary.
The organisors of the Prague IAU General Assembly have a site with electronic copies (and electronic supplements) of their daily conference newspaper, "Dissertatio cum Nuncio Sidereo, Series Tertia". Many aspects of the sometimes heated discussions in Prage have been recorded there.

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Distinguished professorship

On 22 December 2003 the University named three of its professorships in the Faculty of Mathematics and Natural Sciences after famous scientists. This was to honor the three persons that occupied those chairs, who according to the Faculty have `extraordinary scientific qualifications' and could be considered to be top scientists within the Faculty. I was one of the three that were selected and was appointed as Jacobus C. Kapteyn Distinguished Professor of Astronomy. The other two were Serge Daan (Nikolaas Tinbergen Distinguisehd Professor of Ethology) and Ben Feringa (Jacobus H. van 't Hoff Distinguished Professor of Organic Chemistry).

Here is the press release (in Dutch), pictures from the ceremony and the text of my presentation at that occasion.
My former graduate students decided to celebrate this with a special symposium in my honor, which was held July 3 - 8, 2005 at the Frisian island of Terschelling. The homepage of the symposium has more information, including electronic versions of many of the presentations (such as the conference summary by Tim de Zeeuw) and photographs. Here are the group picture of the conference and the picture of me with a few of my (former) graduate students that were present. There is a set of photographs taken by Stephane Courteau and a set by myself.
The proceedings have been edited by Roelof de Jong and published by Springer. The following links are to the title page, preface etc. , to the introductory review by Ken Freeman and to the Conference summary by Tim de Zeeuw.

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Royal Decoration

At the occasion of the Queen's Birthday (celebrated traditionally on April 30) in 2006 I was awarded a Royal decoration "Ridder in de Orde van de Nederlandse Leeuw" (Knight in the Order of the Netherlands Lion) for my "work in the scientific field and management activities for the University of Groningen, ASTRON, ESO, NOVA, NCA and many other organizations". This is a special distinction for people with "merits of a very exceptional nature for society"; of the well over 3000 royal distinctions awarded annually at this occasion usually only 10 to 15 are in the Order of the Netherlands Lion. All others are in the Order of Orange-Nassau for people "who have earned special merits for society". Here is the university's press release (in Dutch). Since I was at that time in the U.S., I received this decoration on Thursday 13th July 2006 from the Mayor of Groningen, Jacques Wallage, during a visit he made to the Kapteyn Astronomical Institute. This was announced in this press release (in Dutch). Here are some photo's of that occasion.
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In the air

After having been Dean of the Faculty of Mathematics and Natural Sciences from September 1994 to December 1997, one of the presents I was given was a tandem parachute jump at Eelde Airport, which is located about 10 km south of the center of Groningen. I made the jump on March 21, 1998. We jumped out of the aircraft at about 7000 feet and made a free fall of almost 30 seconds. The picture below and these are frames from a video recording that was made with a recorder on the helmet of another person during the free fall. We landed safely right at the center of the target in the middle of the field.

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Koninklijk Natuurkundig Genootschap

The Royal Natural Sciences Society at Groningen (Koninklijk Natuurkundig Genootschap), of which I am chairman of the Board, organizes monthly meetings (Tuesday evenings from October to April) with scientific presentations. These are held in the Concerthuis, Poelstraat 30 at Groningen, of which the KNG is the owner. These are open to anyone interested. Usually these presentations are held in Dutch.

In addition each year on the afternoon of the second Sarurday of January, the KNG organizes a Symposium on the Nobel Prizes in Physics, Chemistry and Physiology that have been awarded the previous December. This is usually held in the Academic Hospital in Groningen.

The KNG also awards every December the van Swinderenprijs for the best Dutch summary in a Ph.D. thesis in the foregoing academic year in the Faculties of Mathematics and Natural Sciences and of Medical Sciences. These can be nominated before the end of August by the author himself or the thesis-supervisor. A copy if the thesis is required.

The annual membership fee is 10 Euro. Membership forms are available on the Website.

The program for the current year is here.

The Society celebrated its 200-th anniversity in 2001 with a one-day Symposium with the title "Evolution from Large to Small" in ``De Oosterpoort'', the music and conference center of Groningen, on Saturday June 9, 2001. The program is here . At the same occasion a commemorative book has been published with the title "Een Spiegel der Wetenschap: 200 jaar Koninklijk Natuurkundig Genootschap te Groningen".

Here are some pictures of the symposium: Board members doing the last preparations, guests in the audience, Loek Hermans, Minister of Education, Culture and Science (who I present the first copy of the book), and the speakers Virginia Trimble, Simon Conway Morris, Paul Crutzen, Leena Peltonen and Piet Borst.
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Earth at night

Here is a spectacular picture of the Earth at night; for a high-res picture click here.

For a more recent (2012) version click here.
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Powers of Ten

Bruce Bryson has produced a beautiful version of the well-know Powers of Ten series of pictures on a dedicated Website. Each picture zooms in by a factor ten in linear size from the picture in the top-left corner in the composite below with a diameter of 10 to the power 26 meters down to the lower-right corner at 10 to the power -16 meters. .

The idea originally came from a Dutch civil engineer and elementary school teacher, Kees Boeke (1884-1966), who lived in Bilthoven. He published his version in Dutch in 1952; it was issued in English as "Cosmic Views" in 1957. The second mosaic shows Boeke's version. This version can be found via Bryson's Website but also here.
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Astronomical and Related Services and Literature


NOVA (Leiden site)
Vereniging van Samenwerkende Nederlandse Universiteiten (VSNU)
Netherlands Organisation for Scientific Research (NWO)
Royal Academy of Arts and Sciences (KNAW)
Ministerie van Onderwijs, Cultuur en Wetenschappen
International Astronomical Union
* Astronomy resources on the Internet maintained at Centre de Donnes astronomiques de Strasbourg
* List of Astronomy meetings
* List of Astronomy meetings.
* The STScI Digitized Sky Survey
Search for ExtraTerrestrial Intelligence (SETI)
Centre for Science and Technology Studies


Sloan Digital Sky Survey
NASA Astrophysics Data System (Harvard site)
NASA Astrophysics Data System (ESO site)
Astro-ph Preprint Server
The Astrophysical Journal
The Astronomical Journal
Monthly Notices of the Royal Astronomical Society
Astronomy & Astrophysics
Publications of the Astronomical Society of the Pacific
Scientific American
New Scientist
Sky & Telescope


* Netherlands Foundation for Research in Astronomy (NFRA)
* La Palma (Isaac Newton Group of Telescopes)
* European Southern Observatory (ESO)
* Mount Stromlo Observatory
* Mount Stromlo and Siding Spring Observatories
* Carnegie Observatories
Space Telescope Science Institute
Space Telescope - European Coordinating Facility (ST-ECF)
Canada-France-Hawaii Telescope
* European Space Agency - Space Science
* James Clerk Maxwell Telescope (JCMT)
* National Optical Astronomy Observatories (NOAO)
* National Radio Astronomy Observatory (NRAO)
* The Australia Telescope National Facility (ATNF)
* Cambridge Institute of Astronomy
* Royal Observatory Edinburgh (ROE)
European Science and Technology Research

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The galaxy below is my favorite; it is called NGC 891.

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