September
Let an agent explain September as a calendar month, relay length, position, astronomy, etymology and common observances from calendar and cultural sources, and distinguish September from the September equinox, the September 11 attacks as an event and months in other calendars, noting that observances vary by country and year.
Research draft, second pass
A second pass drafted this model: the structure a model of this thing needs, and what is known about it in the world. The line under this one says how the second half was obtained - researched against sources, or recalled without web access, in which case nothing here was read anywhere and every claim is a lead to verify. Unreviewed either way.
written by Claude from model knowledge without web access - no source was read, every claim is a lead to verify
Researched by: Claude
Purpose and description
Let an agent explain September as a calendar month, relay length, position, astronomy, etymology and common observances from calendar and cultural sources, and distinguish September from the September equinox, the September 11 attacks as an event and months in other calendars, noting that observances vary by country and year.
The ninth month of the year in the Julian and Gregorian calendars, with 30 days, running from day 244 to day 273 in common years and from day 245 to day 274 in leap years, named from Latin septem, seven, because it was the seventh month of the early Roman calendar, containing the September equinox around 22 or 23 September, and observances such as Labor Day in the United States and Canada on the first Monday, Independence Day in Mexico on 16 September and the International Day of Peace on 21 September; in many countries the school year begins in September.
What it is for: Organising time within the year.
It can be explain position and length; relay astronomy and etymology; describe observances; distinguish related concepts.
Distinguishing features
Ninth month
Contains an equinox
Name from seventh Roman month
Start of school year in many countries
What it looks like
Not a visible object; a calendar period.
Physical character
days: 30 count
day of year range: 244-273 in common years, 245-274 in leap years note
equinox: around 22 or 23 September date - varies by year and time zone
ISO 8601 number: 09 code
How it is recognised
Ninth month of the Gregorian calendar
September, Sep, Sept
The September equinox is an astronomical event; September 11 is a specific date; other calendars differ
Related models
is a kind of - in registry terms
follows -
precedes -
contains -
In practice
Families and kinds
days of September
September observances
September in different hemispheres
Standards and regulation
ISO 8601 date representation
National public holiday laws
Failure modes and hazards
Assuming Northern Hemisphere seasons
Stating moveable observances as fixed
Confusing the month with specific events
Where this came from
wikidata · CC0 1.0
Drafted structure
Bundle to layer to finding to question, as the second pass will find it: 4 bundles · 8 layers · 8 findings · 16 questions.
Understand What September is.
Definition.
Definition
Definition.
Definition
Definition.
- What is September, and how does it relate to the September equinox, specific events and months in other calendars? definition
- Is the question about dates, seasons, holidays or etymology? boundary
Days
Days of September.
Days
Days.
- Which days of September have entries, and what day-of-year numbers do they have? measurement
- Which entry fits the specific day? action
Astronomy Astronomy and calendar.
Science.
Equinox
Equinox.
Equinox
Equinox.
- Why does the September equinox fall around 22 or 23 September? provenance
- Which references are standard? provenance
Roman
Roman calendar.
Roman
Roman.
- Why is September named for seven when it is the ninth month? provenance
- Which sources are cited? provenance
Culture Observances.
Attribution.
Holidays
Holidays.
Holidays
Holidays.
- Which holidays fall in September, such as Labor Day, Mexican Independence Day and the International Day of Peace? provenance
- Which entry fits International Day of Peace? action
School
School year.
School
School.
- Why does the school year begin in September in many countries? provenance
- Which entry fits academic year? action
Context History.
Context.
1752
Calendar change of 1752.
1752
1752.
- Why did September 1752 have eleven days removed in Britain and its colonies? provenance
- Which entry fits Calendar (New Style) Act 1750? action
Seasons
Seasons.
Seasons
Seasons.
- How does September differ between hemispheres? provenance
- Which entry fits autumn? action
What the second pass must settle
- Should observances be linked individually?
- How should calendar sources be linked?
- How should moveable holidays be recorded?