Copyright 1999 M.Fuhs

 The July setting sun casts its brilliance
over Lake of the Woods, Ontario

The principle of Rayleigh Scattering explains the red or orange sunsets.  As the sun moves lower in the sky, its light has to travel through "more" of the atmosphere since the sun is at a much lower angle.  In fact at the horizons on a level plane, the atmosphere is about 40 times more thick than it is directly overhead.  Particles and molecules in the atmosphere will scatter out the shorter wavelengths (blue in the color spectrum) more easily than longer ones (red).  Thus, we are left with the reddish portion of the light spectrum to see.  

Season Starting Dates and Times
2013
Spring
Mar 20
6:02 AM CDT
Summer
Jun 21
12:04 AM CDT
Autumn
Sep 22
3:44 PM CDT
Winter
Dec 21
11:11 AM CST
2014
Spring
Mar 20
11:57 AM CDT
Summer
Jun 21
5:51 AM CDT
Autumn
Sep 22
9:29 PM CDT
Winter
Dec 21
5:03 PM CST

 

                2013 Major Meteor Showers
Shower
Peak Time
ZHr*
Interference in northern plains
Quadrantids
Pre-dawn hours Jan 3
50-100
Waning gibbous Moon gives major interference

Lyrids

Pre-dawn hours Apr 22

15-20

Waxing gibbous Moon gives major interference until moonset

Eta Aquarids

Pre-dawn hours May 5

10-20

Near new Moon, no interference.  This shower favors the southern hemisphere and tropical northern hemisphere, but is viewable in the northern plains.

Delta Aquarids
Pre-dawn hours July 28-Aug 2
15-20
Broad peaked shower.  Waning Gibbous moon will give some interference.  Early August may be better then late July due to less Moon interference.  Also favors southern hemisphere and tropical northern hemisphere.
Perseids
Aug 10–13
50-100
Waxing crescent Moon.  No interference after midnight each night
Orionids
Pre dawn hours Oct 21
25
Major interference from waning gibbous Moon

South Taurids

Late evening Nov 4 to dawn Nov 5

5-10

 Near new Moon, no interference

North Taurids

Late evening Nov 11 to dawn Nov 12

5-10

 Waxing gibbous Moon provides major interference until the pre dawn hours after moonset

Leonids
Pre-dawn hours Nov 17
15
Full Moon, major interference
Geminids
Late evening Dec 13 to dawn Dec 14
50-100
Waxing gibbous Moon provides major interference until the pre dawn hours of Dec 14 after moonset

*ZHr is the maximum numbers of meteors expected per hour at Zenith (straight up in sky) and under a very dark sky.

  

These pages were developed in response to public inquiries concerning astronomical data.  


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