MONTHLY OBSERVER’S CHALLENGE

Compiled by:

Roger Ivester, North Carolina

&

Sue French, New York

May 2021

Report #148

Messier 3 (NGC 5272), Globular Cluster in Canes Venatici

Sharing Observations and Bringing Amateur Astronomers Together

Introductio

This month’s target

Charles Messier discovered M3 on 3 May 1764 with a 3.5-inch refractor. The French text of Messier’s catalog in the Connaissance des Temps translates into English as: “Nebula discovered between the Herdsman and one of the Hunting Dogs of Hevelius; it does not contain a star, the center is brilliant & its light imperceptibly fades, it is round; when the sky is good, one can see it with a refractor of one foot [at the time, telescopes were generally described by their length]; it is reported on the Chart of the Comet observed in 1779. Mémoires de l’Académie of the same year. Reexamined 29 March 1781, still very beautiful.”

According to William H. Harris’ Catalog Of Parameters For Milky Way Globular Clusters,

http://physwww.mcmaster.ca/~harris/mwgc.dat , M3 resides 10.2 kiloparsecs (~33,000 light-years) away from us and 12.0 kiloparsecs (~39,000 light-years) from the galactic center. It shines with an integrated V-magnitude of 6.19, and the spectral type of the integrated cluster light is F6. Does its color look slightly yellow to you?

May 2021 Observer’s Challenge Complete Report: may-2021-observers-challenge-_m3-2