March Hare precession of the equinoxes? (APOD 20 Mar 2008)

Comments and questions about the APOD on the main view screen.
Post Reply
User avatar
neufer
Vacationer at Tralfamadore
Posts: 18805
Joined: Mon Jan 21, 2008 1:57 pm
Location: Alexandria, Virginia

March Hare precession of the equinoxes? (APOD 20 Mar 2008)

Post by neufer » Thu Mar 20, 2008 1:45 pm

http://apod.nasa.gov/apod/ap080320.html
-------------------------------------------------------------
<<A bright idea came into Alice's head. 'Is that the reason
. so many tea-things are put out here?' she asked.
'Yes, that's it,' said the Hatter with a sigh:
'it's always tea-time, and we've no time
. to wash the things between whiles.'
'Then you keep moving round, I suppose?' said Alice.
'Exactly so,' said the Hatter: 'as the things get used up.'
'But what happens when you come to the beginning again?'
Alice ventured to ask. 'Suppose we change the subject,'>>
.
<<'I want a clean cup,' interrupted the Hatter:
. 'let's all move one place on.'
He moved on as he spoke, and the Dormouse followed him:
the March Hare moved into the Dormouse's place, and Alice
rather unwillingly took the place of the March Hare. The Hatter
was the only one who got any advantage from the change:
and Alice was a good deal worse off than before, as the
March Hare had just upset the milk-jug into his plate.>>
-------------------------------------------------------------
  • <<The "T" party "precesses" around the table in a clock-wise
    fashion emulating the precession of the equinoxes.
    The "precession" places Hatter at the teapot (Sagittarius).
    The March Hare upsets of the milk-jug (during a
    discussion of drawing water/treacle) indicating that
    the "March equinox" has moved into Aquarius. However,
    Alice (with a May 4th birthdate) remains stuck in Pisces.>>
    http://www.earthvisions.net/bcp/aster/c ... ns/Sgr.htm
------------------------------------------------------------
Art Neuendorffer

ruff_hi
Asternaut
Posts: 2
Joined: Thu Mar 20, 2008 3:13 pm

Not Quite Accurate

Post by ruff_hi » Thu Mar 20, 2008 3:27 pm

Known as the equinox, the geocentric astronomical event marks the first day of spring in the northern hemisphere and autumn in the south.
All seasons in Australia start on the first day of a month. For example: Summer in Australia starts on December 1. For reference ... http://www.bom.gov.au/climate/environ/t ... titialskip

User avatar
neufer
Vacationer at Tralfamadore
Posts: 18805
Joined: Mon Jan 21, 2008 1:57 pm
Location: Alexandria, Virginia

Re: Not Quite Accurate

Post by neufer » Thu Mar 20, 2008 4:40 pm

ruff_hi wrote:
Known as the equinox, the geocentric astronomical event marks the first day of spring in the northern hemisphere and autumn in the south.
All seasons in Australia start on the first day of a month. For example: Summer in Australia starts on December 1. For reference ... http://www.bom.gov.au/climate/environ/t ... titialskip
http://en.wikipedia.org/wiki/Winter

<<It is often said that, astronomically, winter starts with the winter solstice and ends with the vernal equinox. In meteorology, it is by convention counted instead as the whole months of June, July and August in the Southern Hemisphere and December, January and February in the Northern Hemisphere.
.
In Celtic nations such as Ireland using the Irish calendar, the winter solstice is traditionally considered as midwinter, with the winter season beginning November 1 on All Hallows or Samhain. Winter ends and spring begins on Imbolc or Candlemas, which is February 1 or February 2. This system of seasons is based on the length of days exclusively. The three-month period of the shortest days and weakest solar radiation occurs during November, December and January in the Northern Hemisphere and May-July in the Southern Hemisphere.
.
Also many mainland European countries tend to recognize Martinmas, St. Martin's day (November 11) as the first calendar day of winter. The day falls at midpoint between the old Julian equinox and solstice dates. Also, Valentines Day (February 14) is recognized by some countries as heralding the first rites of Spring (season), such as flower blooming. In Chinese astronomy (and other East Asian calendars), winter is taken to commence on or around November 7, with the Jiéqì known as (立冬 lì dōng, literally "establishment of winter".)
.
The three-month period associated with the coldest average temperatures typically begins somewhere in late November or early December in the Northern Hemisphere. If "winter" is defined as the statistically coldest quarter of the year, then the astronomical definition is too late by almost all local climate standards, and the traditional English/Irish definition of November 1 (May 1 in the Southern Hemisphere) is usually too early to fit this standard.>>
Art Neuendorffer

Arramon
Science Officer
Posts: 210
Joined: Mon Sep 13, 2004 2:52 pm

Post by Arramon » Fri Mar 21, 2008 6:31 am

Image

we don't have blue sky in these parts... more grayish blue. meh... really surprises me to see the difference between the valley and the bay along the coast (San Francisco). the astronauts must have it faaaaaantabulous up there in the space station.

ruff_hi
Asternaut
Posts: 2
Joined: Thu Mar 20, 2008 3:13 pm

Re: Not Quite Accurate

Post by ruff_hi » Fri Mar 21, 2008 10:21 am

neufer wrote:<<It is often said that, astronomically, winter starts with the winter solstice and ends with the vernal equinox. In meteorology, it is by convention counted instead as the whole months of June, July and August in the Southern Hemisphere and December, January and February in the Northern Hemisphere.
That is interesting. So there is a difference betwee astronomical and meteorological seasons. I've lived in Aust, UK and the US. I would say that Aust and (IIRC) the UK use the meteorological definition (when I say 'use', I mean the person in the street or the early morning TV show) while the US use the astronomical definition.

User avatar
neufer
Vacationer at Tralfamadore
Posts: 18805
Joined: Mon Jan 21, 2008 1:57 pm
Location: Alexandria, Virginia

Post by neufer » Fri Mar 21, 2008 12:56 pm

Arramon wrote:we don't have blue sky in these parts... more grayish blue. meh... really surprises me to see the difference between the valley and the bay along the coast (San Francisco). the astronauts must have it faaaaaantabulous up there in the space station.
Volcanic dust and other aerosols also collect in the (San Francisco like) temperature inversion situation of the lower stratosphere as can be seen in this APOD picture between the blue upper stratosphere and the red troposphere. By blocking the blue of the upper sky it makes for prettier sunset on earth (but not from space).
Art Neuendorffer

apodman
Teapot Fancier (MIA)
Posts: 1171
Joined: Wed Aug 15, 2007 6:48 pm
Location: 39°N 77°W

Post by apodman » Sat Mar 22, 2008 12:40 am

The obvious advantage in using astronomical rather than meteorological seasons is that the American meteorologist gets to make a big deal four times a year over the dates and times of the equinoxes and solstices to celebrate the change of the seasons. It fills otherwise empty and wasted broadcast time.

At least that's the excuse for the common man. Our excuse is that we're all first and foremost astronomers here, aren't we? We only learned meteorology so we could predict weather for good seeing, remember?

At the bottom line where the astronomical meets the meteorological to create the gastronomical, we have the crop planting and harvest schedule business down to a science. Call the seasons what you want, but farmers with calendars and soil temperature thermometers will not be fooled at all.

User avatar
neufer
Vacationer at Tralfamadore
Posts: 18805
Joined: Mon Jan 21, 2008 1:57 pm
Location: Alexandria, Virginia

Post by neufer » Sat Mar 22, 2008 1:21 am

apodman wrote:The obvious advantage in using astronomical rather than meteorological seasons is that the American meteorologist gets to make a big deal four times a year over the dates and times of the equinoxes and solstices to celebrate the change of the seasons. It fills otherwise empty and wasted broadcast time.
In the United States and Canada the local woodchuck determines whether we go astronomical or quasi-meteorological:
-----------------------------------------------------
First D.J.: Okay, campers, rise and shine, and don't forget your booties 'cause it's cooooold out there today.

Second D.J.: It's coooold out there every day. What is this, Miami Beach?

First D.J.: Not hardly. And you know, you can expect hazardous travel later today with that, you know, that, uh, that blizzard thing.

Second D.J.: [mockingly] That blizzard - thing. That blizzard - thing. Oh, well, here's the report! The National Weather Service is calling for a "big blizzard thing!"

First D.J.: Yessss, they are. But you know, there's another reason why today is especially exciting.

Second D.J.: Especially cold!

First D.J.: Especially cold, okay, but the big question on everybody's lips...

Second D.J.: - On their chapped lips...

First D.J.: - On their chapped lips, right: Do ya think Phil is gonna come out and see his shadow?

Second D.J.: Punxsutawney Phil!

First D.J.: Thats right, woodchuck-chuckers
- it's [in unison] GROUNDHOG DAY!
-----------------------------------------------------
  • http://en.wikipedia.org/wiki/Groundhog_Day
    .
    <<Groundhog Day is a holiday celebrated in the United States and Canada on February 2. In weather lore, if a groundhog, also known as a woodchuck, marmot, or ground squirrel, emerges from its burrow on this day and fails to see its shadow because the weather is cloudy, winter will soon end. If the groundhog sees its shadow, it will return into its burrow and winter will continue for 6 more weeks. Candlemas is sometimes the same day, and has similar beliefs about the coming weather.
    .
    In western countries in the Northern Hemisphere the official first day of Spring is about six weeks after Groundhog Day, on March 20 or March 21. About 1,000 years ago, before the adoption of the Gregorian calendar when the date of the equinox drifted in the Julian calendar, the spring equinox fell on March 16 instead. This was exactly six weeks after February 2. Some ancient traditions marked the change of season at cross-quarter days such as Imbolc when daylight first makes significant progress against the night. Other traditions held that Spring did not begin until the length of daylight overtook night at the Vernal Equinox. So an arbiter, the groundhog/hedgehog, was incorporated as a yearly custom to settle the two traditions. Sometimes Spring begins at Imbolc, and sometimes Winter lasts 6 more weeks until the equinox.>>
Art Neuendorffer

apodman
Teapot Fancier (MIA)
Posts: 1171
Joined: Wed Aug 15, 2007 6:48 pm
Location: 39°N 77°W

Post by apodman » Sat Mar 22, 2008 4:50 am

Please accept my apology for the accidental redundant phrase "temperature thermometer"; it was written in haste, though it might be used to check my "hot water heater".

Post Reply