False Dawn

on Tuesday, 02 September 2014.

Zodiacal Light

False Dawn

Two of my favorite sky phenomena are the Belt of Venus and Zodiacal Light.  I've written about the Belt of Venus in the Night Sky News and will likely write again about it here but right now, I'm going to focus on the "false dawn".

Zodiacal Light can be seen almost anytime during the year and anywhere on Earth (depending upon the ecliptic)  but it is most starkly evident during the Spring and the Fall. It's a rare sight in populated areas but here in Central Oregon, outside of the cities, we are perfectly situated to enjoy this magical light.

This morning, while driving east through the desert, I was treated to what appeared to be the light from a town reflecting up into the clear sky.  It was about 4:30 AM and, for what it's worth, the closest town to the east of me, Burns,  was about 100 miles away.  There was no light coming from Burns at all.  This cone of light was a "false dawn" or Zodiacal light.

Zodiacal Light can be seen anywhere that is very dark and usually about two hours before dawn or about two hours after sunset. It is caused by grains of cosmic dust in our solar system that reflect the light from the sun. It is very faint and even the slightest glow from city lights and or the moon can make it invisible.

I could go into a long, pseudo-scientific description and reason for why this light occurs but suffice it to say that it is magical to our eyes and a lovely addition to a clear dark sky (unless you are doing astro-photography).  It often appears as a pyramid of faint light that extends from the horizon to zenith.  

If you can see the Milky Way, you are likely to see the false dawn or the evening version depending on the time of the year.  It's worth hunting down and a wonderful "add" to your bucket list of Night Sky objects.

Comments (0)

Leave a comment

Please login to leave a comment.