(apart from my
August, 2019: solar spectrum formation for irradiancers, a
brief tutorial expanding my
in a review article published here
- but better view the
because the publisher destroyed 100+ citation links
( more Springer
A year at Sunspot.
Reminiscenses of 1977 - 1978 at the Sacramento Peak Observatory.
January, 2018: renewed IDL programs to obtain and co-align
image cutout sequences from the
Dynamics Observatory. See
Also a multi-movie browser and blinker
The Sun with ALMA: jets and
contrails! at the
72th Nederlandse Astronomenconferentie.
for clickers that open specific pages
with cited figures, tables, equations, etc.
November, 2015: new edition of
to Astrophysical Radiative Transfer"
by Luc Rouppe van der Voort
March 1, 2012:
November 25, 2011: my last day at the
SIU. As farewell I
scanned the courses of M.G.J. Minnaert with which I started my 50
years in Utrecht astronomy.
I also scanned vintage lecture notes by C. Zwaan and his high-school
texts with J. van der Rijst (all in Dutch, under
Cleaning out my desk also made me scan or retrieve ancient courses
"Natuurkunde van zon en sterren"
"Opwekking en transport van straling"
"Introduction to Solar Spectrum Formation"
"Generation and Transport of Radiation"
"Solar and Stellar Magnetism"
January 2011: end of operation funding for the
Dutch Open Telescope.
It is mothballed since - you are welcome to revive it.
"citeads" latex commands
that generate citations in a pdf file which
link to the corresponding ADS abstract page.
"solabs" solar abstracts
with ADS and ArXiv links for many solar
September 2010: updates of my
simple IDL manuals.
August 2010: a
speckle demonstration movie
USO School "Solar Magnetism"
held at ASTRON, Dwingeloo, The
Nederlandsch-Indisch Java and Sumatra
taken by my father during 1936-1939.
of the 12th European Solar
in a new webpost format for talks.
farewell party at Sonnenborgh
at my mandatory retirement.
which I led during 1998 -
( in memoriam).
200-km kayak voyage circuiting
the "Eye of Quebec" asteroid impact.
Epsilon, written in 1997 in memory
of Richard N. Thomas, was finally published.
review of solar
C. ("Kees") de Jager's 80th birthday.
November 2000: the
housing of Utrecht
February 2000: Cornelis ("Kees") Zwaan obituaries for
Solar Physics, Bull. Am. Astron. Soc.,
and JOSO Annual Report 1999. Also a Zwaan
Zwaan's publication list. Zwaan's correspondence and other
science materials are archived at the
on what one did not
see during the August 11 eclipse (in Dutch). What one did not see
were Fraunhofer lines!
The inner corona is the only sunshine-illuminated body in the entire
solar system that does not show them. Walter Grotrian
explained their absence in 1934 as due to enormous Doppler smearing in
Thomson scattering, but without daring to suggest that such large
electron velocities indicate very high temperature. He did that only
much later, after identifying the few coronal emission lines in the
visible as due to highly ionized iron.
During a total solar eclipse you should particularly appreciate that
the corona basks you in pearly sunshine without Fraunhofer lines (and
polarized as well).
November 1997: photographs of the DOT First Light Ceremony
(featuring Crown Prince Willem-Alexander, Science Minister Jo Ritzen
and many other dignitaries) among other
August 1997: many
thirty-year old astronomer
added to the
June 1995: start of this website, to offer my course notes
"Radiative transfer in stellar atmospheres"
electronically. I am proud that it started
just when the web came of age, at the same time as the second-best
astronomy site: the Astronomy Picture of the Day
(here is the
very first APOD display). The number-one
astronomy site is the ADS literature server, started in 1994 by