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
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
2015
Spring
Mar 20
5:45 PM CDT
Summer
Jun 21
11:38 AM CDT
Autumn
Sep 23
3:20 AM CDT
Winter
Dec 21

10:48 PM CST

 

2015 Major Meteor Showers
Shower
Peak Time
ZHr*
Interference 
Quadrantids
Jan 3-4
50-100
Will be badly interfered by a full moon on January 5th

Lyrids

Evening Apr 22

15-20

Little moon interference, small crescent waxing moon

Eta Aquarids

Approximately May 6

10-20

Near full moon, major interference

Delta Aquarids
July 28
15-20
Full moon on July 31, will provide major interference
Perseids

Late evening Aug 12 to early morning Aug 13

100
Little to no moon interference, small crescent waxing moon
South Taurids
Night of Oct 10
5-10
Little to no moon interference, new moon on October 13

Orionids

Late evening Oct 21 to early morning Oct 22

15

Waxing first quarter moon will set before peak Orionid hours after midnight leaving good viewing

North Taurids

Evening Nov 11 to early morning Nov 12

5-10

 Near new Moon, no interference

Leonids

Late evening Nov 17 to early morning Nov 18

15

 Waxing first quarter moon will set shortly after midnight leaving good viewing

Geminids
Evening Dec 13 to early morning Dec 14
120
No interference, waxing crescent moon will set in evening
Ursids
Evening Dec 22 to early morning Dec 23
5-10
Will be badly interfered by a full moon on Dec 25

*ZHr is the maximum numbers of meteors expected per hour at Zenith (straight up in sky) and under a very dark sky.  Average meteor rate can be expected to be less.

  

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


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