Open main menu
Home
Random
Recent changes
Special pages
Community portal
Preferences
About Wikipedia
Disclaimers
Incubator escapee wiki
Search
User menu
Talk
Dark mode
Contributions
Create account
Log in
Editing
Timocharis
(section)
Warning:
You are not logged in. Your IP address will be publicly visible if you make any edits. If you
log in
or
create an account
, your edits will be attributed to your username, along with other benefits.
Anti-spam check. Do
not
fill this in!
==Work== What little is known about Timocharis comes from citations by [[Ptolemy]] in the ''[[Almagest]]''. These indicate that Timocharis worked in Alexandria during the 290s and 280s BC. Ptolemy lists the [[declination]] of 18 stars as recorded by Timocharis or [[Aristillus]] in roughly the year 290 BC.<ref>{{cite journal | last=Newton | first=R. R. | date=1974 | title=The obliquity of the ecliptic two millennia ago | journal=[[Monthly Notices of the Royal Astronomical Society]] | volume=169 | issue=2 | pages=331–342 | bibcode=1974MNRAS.169..331N | doi=10.1093/mnras/169.2.331| doi-access=free }}</ref> Between 295 and 272 BC, Timocharis recorded four lunar [[occultation]]s and the passage of the planet [[Venus]] across a star.<ref>{{cite book | first=Alexander | last=Jones | date=1999 | title=Astronomical papyri from Oxyrhynchus | volume=1–2 | page=84 | isbn=0-87169-233-3 | publisher=DIANE Publishing }}</ref> These were recorded using both the [[Egyptian calendar|Egyptian]] and [[Attic calendar|Athenian]] calendars.<ref>{{citation | last=Jones | first=A. | date=1997 | title=On the reconstructed Macedonian and Egyptian lunar calendars | volume=119 | pages=157–166 | url=http://www.uni-koeln.de/phil-fak/ifa/zpe/downloads/1997/119pdf/119157.pdf | access-date=2009-09-10 }}</ref> The observed stellar passage by Venus may have occurred on October 12, 272 BC when the planet came within 15 [[arcminute]]s of the star [[Eta Virginis|η Virginis]].<ref>{{cite book | author=Fomenko, A. T. | author2=Vi︠a︡cheslavovich, Vladimir Kalashnikov | author3=Nosovskiĭ, Gleb Vladimirovich | title=Geometrical and statistical methods of analysis of star configurations: dating Ptolemy's Almagest | page=215 | publisher=[[CRC Press]] | date=1993 | isbn=0-8493-4483-2 }}</ref> The observations by Timocharis are among the oldest [[ancient Greece|Greek]] records that can be assigned a specific date. They are only exceeded by records of the [[summer solstice]] of 432 BC, as noted by [[Euctemon]] and [[Meton]].<ref name="evans">{{cite book | first=James | last=Evans | date=1998 | title=The History & Practice of Ancient Astronomy | page=259 | publisher=Oxford University Press US | isbn=0-19-509539-1 }}</ref> Timocharis worked with [[Aristillus]] in an astronomical observatory that was most likely part of the [[Library of Alexandria]]. Their equipment would have been simple, most likely consisting of [[gnomon]]s, [[sundial]]s and an [[armillary sphere]]. The two were contemporaries of [[Aristarchus of Samos]], but it is unclear whether there was any association between Timocharis and Aristarchus.<ref>{{cite book | first=George | last=Sarton | date=1993 | title=Hellenistic science and culture in the last three centuries B.C. | page=[https://archive.org/details/hellenisticscien00sart/page/53 53] | publisher=Courier Dover Publications | isbn=0-486-27740-2 | url-access=registration | url=https://archive.org/details/hellenisticscien00sart/page/53 }}</ref> During his astronomical observations, Timocharis recorded that the star [[Spica]] was located 8° west of the [[September equinox|Autumnal equinox]]. Later, [[Hipparchus]] observed that Spica was only 6° west of the Autumnal equinox. Hipparchus was able to deduce the period during which Timocharis made his observations based upon the records of earlier lunar eclipses. From this difference, Hipparchus discovered that the [[longitude]]s of the stars had changed over time, which led him to determine the first value of the [[precession|precession of the equinoxes]] as no less than 1/100° per year.<ref name="evans"/> In approximately 3rd century BC, with the help of [[Aristillus]], he created the first [[star catalogue]] in the Western world.{{Citation needed|date=September 2009}} The crater [[Timocharis (crater)|Timocharis]] on the [[Moon]] is named after him.<ref>{{gpn|6012}}</ref>
Edit summary
(Briefly describe your changes)
By publishing changes, you agree to the
Terms of Use
, and you irrevocably agree to release your contribution under the
CC BY-SA 4.0 License
and the
GFDL
. You agree that a hyperlink or URL is sufficient attribution under the Creative Commons license.
Cancel
Editing help
(opens in new window)