Fun_People Archive
5 Jan
Bits o' TBTF for 1999-01-04: Blue moons

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From: Peter Langston <psl>
Date: Tue,  5 Jan 99 18:23:43 -0800
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Subject: Bits o' TBTF for 1999-01-04: Blue moons

X-Lib-of-Cong-ISSN: 1098-7649
Excerpted-from: TBTF for 1999-01-04: Blue moons
From: Keith Dawson <>

  T a s t y   B i t s   f r o m   t h e   T e c h n o l o g y   F r o n t

  Timely news of the bellwethers in computer and communications
  technology that will affect electronic commerce -- since 1994

  Your Host: Keith Dawson

  This issue: < >

..Blue moons

More than you ever wanted to know about lunar chronology and

  In 1999 January and March will each enjoy two full moons, and Feb-
  ruary will have none at all. This happens far more rarely than once
  in a blue moon, as the second full moon in a month is called. Ac-
  cording to the Blue Moon page [28], blue moons are governed (to a
  first order) by the 19-year Metonic cycle of lunar phases. Over one
  Metonic cycle there are 235 lunar months (236 full moons) and 228
  calendar months. So "once in a blue moon" amounts to about 8 times
  in 228, or 3.5 per cent. (228 calendar months differs from 235 lu-
  nar months by about 2 hours. Then there are leap years to consider.
  Plumb exhaustive detail at [29] and [30]; calculate blue moons for any
  year at [31].) February last lacked a full moon two Metonic cycles
  ago, in 1961, and will miss one again on the next cycle in 2018. The
  last time a moonless February was surrounded by blue moons in
  January and March was in 1915.

  We conclude with an enumeration of the common names for the year's
  full moons, synthesized from a variety of sources [32], [33], [34].

           Algonquin/  English/  neo-Pagan     Other
           colonial    medieval

    Jan    Old         Wolf      Ice           Moon After Yule
    Feb    Hunger      Storm     Snow
    Mar    Crust       Chaste    Death         Sap; Crow; Lenten
    Apr    Pink        Seed      Awakening     Grass; Egg
    May    Flower      Hare      Grass         Planting; Milk
    Jun    Rose        Dyan      Planting      Strawberry; Flower
    Jul    Buck        Mead      Rose          Hay; Thunder
    Aug    Sturgeon    Corn      Lightening    Grain; Dog Days
    Sep    Harvest     Barley    Harvest       Fruit
    Oct    Hunter's    Blood     Blood
    Nov    Beaver      Snow      Tree          Frosty
    Dec    Cold        Oak       Long Night    Moon Before Yule


N o t e s

> TBTF has finally adopted an unambiguous and sort-friendly date term-
  inology based on ISO 8601 [35]. ("And about time!" the readers cry.
  Thanks to Dan Kohn <> for the final push.) I have
  reworked all the internal links on -- please write me if
  you find problems in this area. But feel less compelled to tell me
  about broken external links: the older the issue the less the com-
  pulsion. The links work on the date of publication and I make an
  effort to keep them alive for weeks more, but inevitably linkrot
  [36] sets in over time.


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