skycultures/greek_almagest/description.md
The Almagest consists of 13 sections, called books. In the seventh and eighth book, Ptolemy listed a total of 1022 stars in 48 constellations (among which are about 5 star-like objects like globular star clusters). It is a table of coordinates of the stars with a description of their position in the constellation (such as "star at the elbow of X, longitude, latitude, magnitude"). With regard to precession, Ptolemy used ecliptic coordinates. As one of the first of his time, Ptolemy included the magnitude, a quantitative scale of stellar brightness, probably adopted from Hipparchus (which is not certain because Hipparchus’ catalog is not preserved). The scale starts with the brightest star with the magnitude of 1, going down to magnitude of 6, for the faintest stars visible.
<p>For the computation of planet positions Ptolemy used a geocentric model (which is allowed because the observer always stands on Earth) and, thus, contributed to the scientific belief that the heliocentric model by Aristarch was not needed. However, for the star catalogue of the <i>Almagest</i> this does not matter at all because a star catalogue always represents a sort of inventory of the fixed dots in the sky and Ptolemy's proclaimed aim of the catalogue is to provide a list for making a celestial globe (see Alm., VIII, 3). Being aware of precession he wants to ease the business of future globemakers by using ecliptical coordinates: Precession as known to Ptolemy shifts all stars parallel to the ecliptic, therefore updates to the epoch of the respective globemaker could be applied by a simple subtraction of the value for ecliptic longitude.</p>Out of more than 1,000 stars, Ptolemy mentions a proper name for only 15. The rest are identified by fairly long descriptions such as "The star on the end of the tail" for the Polaris. In order to avoid displaying such long strings across the screen in Stellarium, we invented short labels for all Almagest stars based on the constellation and the order in which they appear in the catalogue. For example, Polaris is given a designation "UMi 1" because it is the first star in the constellation of Small Bear (UMi). See the table below for the correspondence between Ptolemy constellations and IAU abbreviations. In addition, where Ptolemy describes a star as lying outside of the figure, we use lowercase letters in the corresponding label. To see the long description for a given star, users should enable "Use additional names of stars" in the "View [F4]/Sky" settings and click on the star. The long description will then be displayed at the top of the screen.
The process can be described as sketched here with the example of Corvus:
In the constellation of Corvus (Raven), α Crv is the star in the "head of the raven". It is connected with the "star in the neck", ε Crv. This one is connected with "the star in the breast" ζ Crv. From there two lines go to the tips of the wings. γ Crv is the star in the advanced wing and δ Crv the star in the rear wing. From the star in the breast another line goes to the "foot of the raven", the star β Crv.
<p></p> <p>After identifying the stars based on their coordinates and names, we reconnected the stars according to the descriptions in the table presented in the <i>Almagest</i>.</p> <p>The names of stars and names of deep sky objects rely on the Almagest only, e.g. Ptolemy uses the name "λαμπαδίας (The Torch-like)" for Aldebaran in his other work, the <i>Tetrabiblos</i>, but this is not implemented in this sky culture because it doesn't show up in the Almagest.</p>The following table displays the original constellation name in Greek and its English translation (column 2 and 3) and denotes our uncertainties in the reconstruction (column 6).
<table> <tr valign="top"> <td><b>Abbreviation</b></td> <td><b>Original name</b></td> <td><b>Translation</b> (direct)</td> <td><b>IAU (Latin) name</b></td> <td><b>hints to constellation</b></td> <td><b>freedom of art</b></td> </tr> <tr valign="top"> <td><notr>UMi</notr></td> <td><notr>Μικρή ʾˊΑρκτος</notr></td> <td>Small She-Bear</td> <td><notr>Ursa Minor</notr></td> <td>like IAU constellation</td> <td></td> </tr> <tr valign="top"> <td><notr>UMa</notr></td> <td><notr>Μεγαλή ʾˊΑρκτος</notr></td> <td>Great She-Bear</td> <td><notr>Ursa Major</notr></td> <td>like IAU constellation</td> <td></td> </tr> <tr valign="top"> <td><notr>Dra</notr></td> <td><notr>Δράκων</notr></td> <td>Dragon</td> <td><notr>Draco</notr></td> <td>all triangles or squares are vertebra or parts of the body; line at the head is the tongue</td> <td></td> </tr> <tr valign="top"> <td><notr>Cep</notr></td> <td><notr>Κηφεύς</notr></td> <td>Kepheus</td> <td><notr>Cepheus</notr></td> <td>king, upside down </td> <td>three head stars are tiara; β seen as part of the belt, although Almagest says beneath belt</td> </tr> <tr valign="top"> <td><notr>Boo</notr></td> <td><notr>Βοώτης</notr></td> <td>Ploughman</td> <td><notr>Boötes</notr></td> <td>has a shepherd's staff in his hand (ω)</td> <td>star HIP 72582 added as neck star</td> </tr> <tr valign="top"> <td><notr>CrB</notr></td> <td><notr>Στέφανος</notr></td> <td>Crown</td> <td><notr>Corona Borealis</notr></td> <td>like IAU constellation; no details for lines in the text</td> <td></td> </tr> <tr valign="top"> <td><notr>Her</notr></td> <td><notr>ʿΕνγόνασιν</notr></td> <td>Kneeler</td> <td><notr>Hercules</notr></td> <td>one of the foot stars is top of staff of Bootes</td> <td>star HIP 82764 added as neck star</td> </tr> <tr valign="top"> <td><notr>Lyr</notr></td> <td><notr>Λύρα</notr></td> <td>Lyre</td> <td><notr>Lyra</notr></td> <td></td> <td></td> </tr> <tr valign="top"> <td><notr>Cyg</notr></td> <td><notr>ʾˊΟρνις</notr></td> <td>Bird</td> <td><notr>Cygnus</notr></td> <td>swan with legs</td> <td>Tips of wings connected with tail</td> </tr> <tr valign="top"> <td><notr>Cas</notr></td> <td><notr>Κασσιέπεια</notr></td> <td>Kassiepeia</td> <td><notr>Cassiopeia</notr></td> <td>Queen sitting on a throne</td> <td>to avoid confusion we did not draw the throne</td> </tr> <tr valign="top"> <td><notr>Per</notr></td> <td><notr>Περσεύς</notr></td> <td>Perseus</td> <td><notr>Perseus</notr></td> <td>Double star cluster NGC 869 and NGC 884 as Deep Sky Object - >one of the stars in the cluster was used for drawing</td> <td>one of the stars in Gorgon-head is added to make the head look more spherical</td> </tr> <tr valign="top"> <td><notr>Aur</notr></td> <td><notr>ʿΗνίοχος</notr></td> <td>Charioteer</td> <td><notr>Auriga</notr></td> <td>wears long garment; garment limited through shoulders and hem</td> <td>ο Aur added as neck star; 1 Aur added as hem star</td> </tr> <tr valign="top"> <td><notr>Oph</notr></td> <td><notr>ʾΟφιούχος</notr></td> <td>Serpent Bearer</td> <td><notr>Ophiuchus</notr></td> <td>has serpent in his hand</td> <td>a star added as neck star</td> </tr> <tr valign="top"> <td><notr>Ser</notr></td> <td><notr>ʾˊΟφις</notr></td> <td>Snake</td> <td><notr>Serpens</notr></td> <td>two separate parts of the snake (head and tail); square is head</td> <td></td> </tr> <tr valign="top"> <td><notr>Sge</notr></td> <td><notr>ʾΟιστός</notr></td> <td>Arrow</td> <td><notr>Sagitta</notr></td> <td>Like IAU constellation, η Sge is missing </td> <td></td> </tr> <tr valign="top"> <td><notr>Aql</notr></td> <td><notr>ʾΑετός</notr></td> <td>Eagle</td> <td><notr>Aquila</notr></td> <td>τ Aql as head star, β as neck, Altair is between shoulders, γ and μ are shoulders</td> <td></td> </tr> <tr valign="top"> <td><notr>Del</notr></td> <td><notr>Δελφίς</notr></td> <td>Dolphin</td> <td><notr>Delphinus</notr></td> <td></td> <td>refined shape</td> </tr> <tr valign="top"> <td><notr>Equ</notr></td> <td><notr>Προτομή</notr></td> <td>Bust [of a horse]</td> <td><notr>Equuleus</notr></td> <td></td> <td></td> </tr> <tr valign="top"> <td><notr>Peg</notr></td> <td><notr>ʿˊΙππος</notr></td> <td>Horse</td> <td><notr>Pegasus</notr></td> <td>with mane and one wing</td> <td></td> </tr> <tr valign="top"> <td><notr>And</notr></td> <td><notr>ʾΑνδρομέδα</notr></td> <td>Andromeda</td> <td class='latin'><notr>Andromeda</notr></td> <td>dress and belt</td> <td></td> </tr> <tr valign="top"> <td><notr>Tri</notr></td> <td><notr>Τρίγωνος</notr></td> <td>Triangle</td> <td><notr>Triangulum</notr></td> <td>four given stars  middle star of one side</td> <td></td> </tr> <tr valign="top"> <td><notr>Ari</notr></td> <td><notr>Κριός</notr></td> <td>Ram</td> <td><notr>Aries</notr></td> <td>turned head; only one horn</td> <td></td> </tr> <tr valign="top"> <td><notr>Tau</notr></td> <td><notr>Ταυ̃ρος</notr></td> <td>Bull</td> <td><notr>Taurus</notr></td> <td>half body, only two legs visible; direction of view to observer</td> <td></td> </tr> <tr valign="top"> <td><notr>Gem</notr></td> <td><notr>Δίδυμοι</notr></td> <td>Twins</td> <td><notr>Gemini</notr></td> <td>one star in common; touching each other with hands</td> <td></td> </tr> <tr valign="top"> <td><notr>Cnc</notr></td> <td><notr>Καρκίνος</notr></td> <td>Crab</td> <td><notr>Cancer</notr></td> <td>square body</td> <td></td> </tr> <tr valign="top"> <td><notr>Leo</notr></td> <td><notr>Λέων</notr></td> <td>Lion</td> <td><notr>Leo</notr></td> <td>opens jaw</td> <td></td> </tr> <tr valign="top"> <td><notr>Vir</notr></td> <td><notr>Παρθένος</notr></td> <td>Maiden</td> <td><notr>Virgo</notr></td> <td>no separate head</td> <td>fainter stars added to draw the wings</td> </tr> <tr valign="top"> <td><notr>Lib</notr></td> <td><notr>Χηλαί</notr></td> <td>Claws [of the Scorpion]</td> <td><notr>Libra</notr></td> <td>Ptolemy always uses the term "claws", never "the balance".</td> <td></td> </tr> <tr valign="top"> <td><notr>Sco</notr></td> <td><notr>Σκορπίος</notr></td> <td>Scorpion</td> <td><notr>Scorpius</notr></td> <td></td> <td>arms added around the head: ν and ρ</td> </tr> <tr valign="top"> <td><notr>Sgr</notr></td> <td><notr>Τοξότης</notr></td> <td>Archer</td> <td><notr>Sagittarius</notr></td> <td>a centaur with bow ahead; „cloak“ behind</td> <td>we included many faint stars in our stick figure in order to make the picture clear.</td> </tr> <tr valign="top"> <td><notr>Cap</notr></td> <td><notr>Αίγόκερος</notr></td> <td>The One with the Goat's Horn</td> <td><notr>Capricornus</notr></td> <td>fish tail; two legs visible</td> <td></td> </tr> <tr valign="top"> <td><notr>Aqr</notr></td> <td><notr>ʿΥδροχόος</notr></td> <td>Water-Carrier</td> <td><notr>Aquarius</notr></td> <td>water out of jug</td> <td></td> </tr> <tr valign="top"> <td><notr>Psc</notr></td> <td><notr>ʾΙχθύες</notr></td> <td>[2] Fish</td> <td><notr>Pisces</notr></td> <td></td> <td>northern fish: 68(h), 67(k), and 65(i) described as head in Almagest but we took them as fin because mouth should be at g and τ Psc. Additional change on tail fin: extended to ρ</td> </tr> <tr valign="top"> <td><notr>Cet</notr></td> <td><notr>Κη̃τος</notr></td> <td>Sea Monster</td> <td><notr>Cetus</notr></td> <td></td> <td>Body does not go through star τ, but through star υ</td> </tr> <tr valign="top"> <td><notr>Ori</notr></td> <td><notr>ʾΩρίων</notr></td> <td>Orion</td> <td class='latin'><notr>Orion</notr></td> <td></td> <td>The "head" is labeled as "nebulous" which means Ptolemy interpreted φ<sub>1</sub>, φ<sub>2</sub>, and λ, together with fainter stars between them as a "cluster" (or association which is more extended than the modern "λ Ori Assoc."). Head does not have direct connection to the shoulder stars anymore, but a connection to a star between the stars in the shoulders.</td> </tr> <tr valign="top"> <td><notr>Eri</notr></td> <td><notr>Ποταμοός</notr></td> <td>River [nameless]</td> <td><notr>Eridanus</notr></td> <td>Like IAU constellation, but shorter</td> <td></td> </tr> <tr valign="top"> <td><notr>Lep</notr></td> <td><notr>Λαγω̃ς</notr></td> <td>Hare</td> <td><notr>Lepus</notr></td> <td></td> <td>took the "4 stars over the ear" as ear</td> </tr> <tr valign="top"> <td><notr>CMa</notr></td> <td><notr>Κύων</notr></td> <td>Dog</td> <td><notr>Canis Major</notr></td> <td></td> <td></td> </tr> <tr valign="top"> <td><notr>CMi</notr></td> <td><notr>Προκύων</notr></td> <td>The One before the Dog</td> <td><notr>Canis Minor</notr></td> <td></td> <td>In Almagest, the name of the constellation is "The One before the Dog" or "Harbinger of Sirius" as Toomer puts it. However, β CMi is called "the neck" (of whom is unknown).</td> </tr> <tr valign="top"> <td><notr>Arg</notr></td> <td><notr>ʾΑργω</notr></td> <td>Ship "Argo"</td> <td><notr>Argo</notr></td> <td>smaller than the sum of the IAU-constellations Pup+Pyx+Car+Vel</td> <td>Many stars not integrated in the constellation, to create a boat-like shape; in many depictions (including the ancient Farnese globe), only a half of a ship is painted.</td> </tr> <tr valign="top"> <td><notr>Hya</notr></td> <td><notr>ʿˊΥδρος</notr></td> <td>Water Snake</td> <td><notr>Hydra</notr></td> <td>like IAU constellation</td> <td></td> </tr> <tr valign="top"> <td><notr>Crt</notr></td> <td><notr>Κρατ̀ηρ</notr></td> <td>Krater (vessel)</td> <td><notr>Crater</notr></td> <td></td> <td>a Krater is special Greek wine mixing vessel which looks like an amphora or vase: <a href="https://en.wikipedia.org/wiki/Krater">https://en.wikipedia.org/wiki/Krater</a> Ptolemy describes only one star in the foot (α Crt) and two handles (η, θ Crt)</td> </tr> <tr valign="top"> <td><notr>Crv</notr></td> <td><notr>Κóραξ</notr></td> <td>Raven</td> <td><notr>Corvus</notr></td> <td>like IAU constellation</td> <td></td> </tr> <tr valign="top"> <td><notr>Cen</notr></td> <td><notr>Κένταυρος</notr></td> <td>Kentauros</td> <td><notr>Centaurus</notr></td> <td></td> <td>deviation from description: HIP 65373 instead of ω Cen (cluster) taken as star on the back. ‘Thyrsus‘ not drawn (to avoid confusion), backward arm added.</td> </tr> <tr valign="top"> <td><notr>Lup</notr></td> <td><notr>Θηρίον</notr></td> <td>Beast</td> <td><notr>Lupus</notr></td> <td></td> <td>β described as ‘End of hind leg‘ -> taken as star in the belly; τ<sub>1</sub> as hindleg; χ in head, because otherwise shapelessness arises; HIP 73493 taken as foreleg</td> </tr> <tr valign="top"> <td><notr>Ara</notr></td> <td><notr>Θυμιατήριον</notr></td> <td>Altar</td> <td><notr>Ara</notr></td> <td>like IAU constellation</td> <td></td> </tr> <tr valign="top"> <td><notr>CrA</notr></td> <td><notr>Στέφανος Νότιος</notr></td> <td>Southern Crown</td> <td><notr>Corona Australis</notr></td> <td>like IAU constellation; only uncertainty with stars that only got a BSC number in the Almagest, because these are not clearly to identify in Stellarium</td> <td></td> </tr> <tr valign="top"> <td><notr>PsA</notr></td> <td><notr>Νότιος ʾΙχθύς</notr></td> <td>Southern Fish</td> <td><notr>Piscis Austrinus</notr></td> <td>the fish is laying on his back</td> <td>the fish is apparently dead: the belly up, or an eelwith twisted spine; we added a few stars to mark the tail fin whose tip is given as β PsA.</td> </tr> </table>This sky culture originates from a student's year of research. We provide this for free but authors of contributions certainly deserve to be cited according to the common rules. Thank you!
The authors thank Patrick Gleason and Georg Zotti for English proofreading and interesting discussions.
This sky culture was compiled and added to Stellarium by Alina Schmidt, Lea Jabschinski, Marie von Seggern and Susanne M. Hoffmann: [email protected]
Written in English: the authors
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