What is Journey North?
Sunlight and Mystery Class
What is the mystery class?
When does this start?
What will I need to know?
Pnotoperiod: What is it? How to calculate it.
Dates to Record; Dec. 1 and Dec. 22 for your "Home" location which is Irasburg, VT
Record Sunrise, Sunset and calculate the photoperiod.
Figure out the number of hours and minutes between sunrise and sunset. It's easier if you understand military time.
When you go to the site above, enter the day and location. This is what you’d get for Dec. 22:
Example of Sun and Moon Data for One Day:
U.S. Naval Observatory
Astronomical Applications Department
Sun and Moon Data for One Day
The following information is provided for Irasburg, Orleans County, Vermont (longitude W72.3, latitude N44.8):
22 December 2011 Eastern Standard Time
Begin civil twilight 6:50 a.m.
Sunrise 7:24 a.m.
Sun transit 11:48 a.m.
Sunset 4:12 p.m.
End civil twilight 4:45 p.m.
Moonset 1:30 p.m. on preceding day
Moonrise 5:03 a.m.
Moon transit 9:43 a.m.
Moonset 2:19 p.m.
Moonrise 6:11 a.m. on following day
Phase of the Moon on 22 December: waning crescent with 6% of the Moon's visible disk illuminated.
New Moon on 24 December 2011 at 1:07 p.m. Eastern Standard Time.
Definition of Civil twilight (From Wikipedia)
Under civil twilight circumstances, the horizon is clearly visible, and terrestrial objects are easily perceptible without artificial light.
Morning civil twilight begins when the geometric center of the sun is 6° below the horizon (civil dawn) and ends at sunrise. Evening civil twilight begins at sunset and ends when the geometric center of the sun reaches 6° below the horizon (civil dusk).
Most civil laws refer to 30 minutes before/after sunrise/sunset instead of number of degrees. Turning on vehicle lights, hunting laws, are the common laws using the phrase “civil twilight.”