134 research outputs found
Errata in \em {Enclyclopedia of Cosmology}
I have noted a number of errors, most of them quite minor, in the {\em
Encyclopedia of Cosmology} (New York and London: Garland), 1993, Norriss S.
Hetherington, ed. The majority occur in my mathematically verbose article,
``Fundamental cosmological parameters". Some errata were passed on to me by
Prof. Ralph Alpher. In the interests of accuracy, I feel that the corrections
should be publicized, since no book review will mention more than a couple of
them. Also, the incorrectly typeset equations could lead to serious confusion
in the minds of readers seeing such material for the first time.Comment: 5 pages, Late
The Usefulness of Type Ia Supernovae for Cosmology - a Personal Review
We review some results of the past 12 years derived from optical and infrared
photometry of Type Ia supernovae. A combination of optical and infrared
photometry allows us to determine accurately the extinction along the line of
sight. The resulting distance measurements are much more accurate than can be
obtained from optical data alone. Type Ia supernovae are very nearly standard
candles in the near-infrared. Accurate supernova distances, coupled with other
observational data available at present, allow us to determine the matter
density in the universe and lead to evidence for the existence of Dark Energy.
We can now address some questions on the grandest scale such as, "What is the
ultimate Fate of the universe?"Comment: 14 page, 9 figures, to be published in Journal of the American Assoc.
of Variable Star Observer
Strange Cases from the Files of Astronomical Sociology
What astronomer could not use his own surname because his father was beheaded
for sorcery? Who built the only observatory worth $5 billion in today's money?
Who had worse luck than YOU travelling thousands of miles NOT to observe an
astronomical event? Who had one of his books bound in human skin at the request
of his most ardent fan? Is there an anti-correlation between scientific output
and the number of children one has? Are astronomers known for having unusual
honeymoons? Who wrote the most egotistical work in the history of astronomy?
What famous astronomer was present for the opening of King Tutankhamen's tomb
and later began having hallucinations of an elf, which advised him on the
running of his observatory? What is the strangest abstract published in the
Bulletin of the American Astronomical Society? What well-known bad tempered
astronomer was born in 1898 (the year after Bram Stoker's {\em Dracula} was
published) in Varna, Bulgaria, which all vampirologists recognize as the
nearest port from which any self-respecting Transylvanian vampire would embark
on a sea voyage to London? In this article we provide answers to these
fascinating questions.Comment: 7 pages, Late
A Mixture of Ancient and Modern Understanding Concerning the Distance and Motion of the Moon
Ptolemy's model of the Moon's motion implied that its distance varies by
nearly a factor of two, implying that its angular size should also vary by
nearly a factor of two. We present an analysis of 100 naked eye observations of
the Moon's angular size obtained over 1145 days, showing regular variations of
at least 3 arc minutes. Thus, ancient astronomers could have shown that a key
implication of Ptolemy's model was wrong. In modern times we attribute the
variation of distance of the Moon to the combined effect of the ellipticity of
the Moon's orbit and the perturbing effect of the Sun on the Earth-Moon system.
We show graphically how this affects the ecliptic longitudes and radial
distance of the Moon. The longitude and distance "anomalies" are correlated
with the Moon's phase. This is illustrated without any complex equations or
geometry.Comment: 10 pages, 4 figures; to be published in Asian Journal of Physic
Observatories
I give a brief history of astronomical observatories as an institution. This
includes: 1) observatories in Islam; 2) China and India; 3) early European
observatories; 4) the rise of national observatories; 5) private (amateur)
observatories; 6) mountaintop observatories and the modern era. Additional
references, to material not cited in the version that will be published in the
encyclopedia, are also given.Comment: 12 pages, 1 postscript figure included, for Encyclopedia of Astronomy
and Astrophysics, Institute of Physics Publishin
A Brief History of Astronomical Brightness Determination Methods at Optical Wavelengths
In this brief article I review the history of astronomical photometry,
touching on observations made by the ancient Chinese, Hipparchus and Ptolemy,
the development of the concept (and definition) of magnitude, the endeavors of
Argelander and Zoellner, work at Harvard at the end of the 19th century, and
the development of photography, photomultipliers, and CCD's and their
application to astronomy.Comment: 13 pages, 2 figures, 40 reference
Where Did Copernicus Obtain the Tools to Build His Heliocentric Model? Historical Considerations and a Guiding Translation of Valentin Rose's "Ptolemaeus und die Schule von Toledo" (1874)
We present a translation of the German text of an 1874 article by Valentin
Rose that concerns the possible school of translators that worked in Toledo,
Spain, from about 1150 to 1250. Rose's article relies significantly on the
first-hand account of the activities in Toledo by the Englishman Daniel of
Morley. The most prolific translator in Toledo was Gerard of Cremona, who
translated Ptolemy's Almagest from Arabic into Latin with the help of Galib the
Mozarab; this translation was significant to Copernicus's work. Georg Peurbach
and Regiomontanus based their Epitome of the Almagest (1463) on Gerard's
translation, which in turn introduced Greek astronomy to astronomers in Italy
and throughout Europe. Copernicus studied in Padua in the first few years of
the sixteenth century, where he learned about Ptolemy's Almagest. Copernicus's
book De Revolutionibus (1543) also contains two geometrical tools of
astronomers from thirteenth century Maragha, and his model of the motion of the
Moon is mathematically identical to that of Ibn al-Shatir (fourteenth century
Damascus). A Greek language manuscript written prior to 1308, and the residence
in Padua of Moses Galeano, a Jewish scholar from Constantinople and Crete, who
was familiar with the work of Ibn al-Shatir, provide evidence of the
transmission of Arabic astronomical ideas to Copernicus. We have only begun to
understand this conduit of transmission.Comment: 26 page
At What Distance Can the Human Eye Detect a Candle Flame?
Using CCD observations of a candle flame situated at a distance of 338 m and
calibrated with observations of Vega, we show that a candle flame situated at
~2.6 km (1.6 miles) is comparable in brightness to a 6th magnitude star with
the spectral energy distribution of Vega. The human eye cannot detect a candle
flame at 10 miles or further, as some statements on the web suggest.Comment: 9 pages, 6 figure
The Sign of Four: A new class of cool non-radially pulsating stars?
In this paper we discuss four early F-type variable stars whose periods are
an order of magnitude slower than known pulsators of comparable luminosity.
They cannot be stars undergoing simple radial pulsations. For one or more of
these stars we can discount the possibility that the variability is due to
rotational modulation of star spots, interactions with (or tidal distortions
by) a close companion, or obscuration by a rotating lumpy ring of dust orbiting
the star. They are certainly not eclipsing binaries. The only possibility left
seems to be non-radial pulsations, though this explanation involves
difficulties of its own. If they are indeed pulsating stars exhibiting non-
radial gravity modes, they would be the first stars on the cool side of the
Cepheid instability strip in the Hertzsprung-Russell Diagram to be so
identified.Comment: 16 pages Latex, 1 ASCII table, 3 figures (available from author
New Photometry of the Hyades Scuti star V777 Tau (71 Tau)
71 Tau was discovered to be a Scuti star by Horan (1979, AJ 84,
1770). To our knowledge no other photometry of this star has been published. 71
Tau is the second brightest X-ray source in the Hyades and has been shown to be
variable by as much as 30 \% at ultraviolet wavelengths near 1700 to 2000 \AA.
We find that the best two-frequency fit to the new photometry is obtained with
= 5.485 and = 7.637 d, with amplitudes = 6.0 and
= 3.4 mmag, respectively. However, one-day aliases of these frequencies
{\em could} be the true values. (For Scuti stars pulsating radially
the ratio of first overtone period to fundamental period is 0.773.) It would be
useful to obtain more extensive data runs on this and other Scuti
stars in the Hyades.Comment: 2 pages, Latex; uses IBVS.STY; 3 figures, available via Fax or ftp at
ftp://ftp.jach.hawaii.edu/usr/local/ukirt/ftp/kevin ; to appear as
Information Bulletin on Variable Stars, No. 426
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