Claire Brock
Teoksen The Comet Sweeper: Caroline Herschel's Astronomical Ambition tekijä
Tietoja tekijästä
Claire Brock is a lecturer in the English Department at the University of Leicester, UK.
Image credit: University of Leicester
Tekijän teokset
Merkitty avainsanalla
Yleistieto
- Sukupuoli
- female
- Palkinnot ja kunnianosoitukset
- British Society for the History of Science Singer Prize (2004)
Jäseniä
Kirja-arvosteluja
Tilastot
- Teokset
- 3
- Jäseniä
- 58
- Suosituimmuussija
- #284,346
- Arvio (tähdet)
- 3.1
- Kirja-arvosteluja
- 2
- ISBN:t
- 9
*Despite being denied an education and turned into a domestic servant by her mother (her father Isaac was supportive but too easy-going to argue with his wife) she taught herself to play the violin.
*Breaking free of Hannover and her now widowed mother’s household on the invitation of her musician brother William, she journeyed to Bath, England, and became an accomplished singer. (Her method for learning to sing seems strange, but was apparently common in the 18th century – she practiced with a gag in her mouth. I’ve seen pictures of that on the Internet, but never realized opera was involved).
*When her brother abandoned his musical career to become an astronomer, Caroline dutifully accompanied him and became his observing assistant, carefully noting positions dictated by William, keeping papers and star catalogs in order, and generally being “invaluable” (in William’s words).
*When not required by William, Caroline took up her own observing program, eventually discovering seven comets.
The problem here is Brock’s explanation of what was involved in 18th century telescopic astronomy is badly muddled. All of William Herschel’s telescopes were reflectors with what we would now call altazimuth mountings, and pretty crude ones at that. (Brock has a hopelessly confused description of the difference between and relative merits of the reflectors and refractors of the time).
Any celestial object observed with the rig had to have its coordinates converted to right ascension and declination (Brock refers to “night ascension” several times; I suspect a misunderstanding except sometimes it’s in direct quotes from one of the Herschel’s letters. Perhaps that’s what they called it then). I have no idea how this was done. Pictures of Herschel’s telescopes don’t seem to have any sort of indices or scales for measuring an object’s position; I can only assume they aren’t visible or have been removed. You can determine right ascension without scales by starting with an object of known position and timing how long it takes the target object to come into view (and there’s a hint it might have been done this way, since Caroline Herschel records consulting the clocks as one of her duties) but declination measurement requires some sort of scale. To get there with an altazimuth mounting you have to have the telescope’s position accurately surveyed (apparently Caroline helped with that too; Brock says she “learned to use rods to measure the ground” without explaining why), know the time of the observation as precisely as possibly, measure the object’s distance above the horizon (ideally, an artificial horizon) or from the zenith or from another object of known position, and do spherical trigonometry. Caroline Herschel was responsible for resolving these observations and making fair copies of the results – William Herschel sometimes called out object positions at the rate of six a minute. Her mathematics, beyond basic arithmetic, was entirely self-taught. This is vastly more impressive than her comet discoveries – which could have been made by anybody with reasonable perseverance.
Ironically, while Brock claims that modern histories have relegated Caroline Herschel to a footnote to her brother’s accomplishments, her contemporaries and near contemporaries were seemingly quite aware of what was involved. Francis Baily, Neville Maskelyne, John Dreyer, and Joseph de Lalande all praised Caroline Herschel’s abilities (de Lalande named his daughter “Caroline” in her honor; he’d named his son “Isaac” after Newton) as an observing assistant; unfortunately Brock only mentions this in passing and almost as if it were sort of a patronizing insult.
Good enough as a straightforward biography but not adequate as a description of 18th century astronomy, regardless of the astronomer’s gender.… (lisätietoja)