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Four Instruments in Martín Cortés' Breve Compendio de la Sphera and a Rule for Finding the Age of the Moon

Gislén, Lars LU (2024) In Journal of Astronomical History and Heritage 27(1). p.53-62
Abstract
This paper investigates and discusses four instruments found in a sixteenth century Spanish book of navigation. The night clock is a rather standard application of similar instruments known since the fourteenth century in Europe. Cortés’ explanation of the causes of the deviation of the magnetic and geographical north is quite original. His instrument to correct for that the Polaris deviates from the North Celestial Pole is an original way of presenting the practical tradition of Spanish mariners. The general sundial is essentially a copy of the same instrument appearing in in Peter Apian’s books Cosmographia LIber and Ein kunstlich Instrument but with an addition for finding the azimuth of sunrise and sunset. The paper also investigates a... (More)
This paper investigates and discusses four instruments found in a sixteenth century Spanish book of navigation. The night clock is a rather standard application of similar instruments known since the fourteenth century in Europe. Cortés’ explanation of the causes of the deviation of the magnetic and geographical north is quite original. His instrument to correct for that the Polaris deviates from the North Celestial Pole is an original way of presenting the practical tradition of Spanish mariners. The general sundial is essentially a copy of the same instrument appearing in in Peter Apian’s books Cosmographia LIber and Ein kunstlich Instrument but with an addition for finding the azimuth of sunrise and sunset. The paper also investigates a simple rule for finding the age of the Moon for any date. Observations of the Moon and its phases were an important part of navigational art for predicting with the tides. (Less)
Please use this url to cite or link to this publication:
author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Journal of Astronomical History and Heritage
volume
27
issue
1
pages
10 pages
publisher
National Astronomical Research Institute of Thailand
ISSN
1440-2807
DOI
10.3724/SP.J.1440-2807.2024.01.04
language
English
LU publication?
yes
id
d5f4a28e-4261-473e-bdc6-d6b4b326875c
date added to LUP
2024-04-02 09:22:05
date last changed
2024-04-02 14:35:26
@article{d5f4a28e-4261-473e-bdc6-d6b4b326875c,
  abstract     = {{This paper investigates and discusses four instruments found in a sixteenth century Spanish book of navigation. The night clock is a rather standard application of similar instruments known since the fourteenth century in Europe. Cortés’ explanation of the causes of the deviation of the magnetic and geographical north is quite original. His instrument to correct for that the Polaris deviates from the North Celestial Pole is an original way of presenting the practical tradition of Spanish mariners. The general sundial is essentially a copy of the same instrument appearing in in Peter Apian’s books Cosmographia LIber and Ein kunstlich Instrument but with an addition for finding the azimuth of sunrise and sunset. The paper also investigates a simple rule for finding the age of the Moon for any date. Observations of the Moon and its phases were an important part of navigational art for predicting with the tides.}},
  author       = {{Gislén, Lars}},
  issn         = {{1440-2807}},
  language     = {{eng}},
  number       = {{1}},
  pages        = {{53--62}},
  publisher    = {{National Astronomical Research Institute of Thailand}},
  series       = {{Journal of Astronomical History and Heritage}},
  title        = {{Four Instruments in Martín Cortés' Breve Compendio de la Sphera and a Rule for Finding the Age of the Moon}},
  url          = {{http://dx.doi.org/10.3724/SP.J.1440-2807.2024.01.04}},
  doi          = {{10.3724/SP.J.1440-2807.2024.01.04}},
  volume       = {{27}},
  year         = {{2024}},
}