6080
They are given in Aratus ' work " Phenomena " and Ptolemy 's " Almagest " , though their origin probably predates these works by several centuries .
 Aratus, Ptolemy
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: location, person, organization 
Text: {0} 
Answer:
 Aratus, Ptolemy