March 2nd is your next chance!

Upper image - Zodiacal light from Europe. Taken in Wiltshire, England on 14th February by Richard Fleet webmaster of Glows Bows & Haloes. 60s unguided exposure at f/4 ISO 1600, Canon 20D, Sigma 10-20mm lens at 10mm. Unprocessed JPG.

Lower image - On the same night by Claudia Hinz (Atmospheric optics site) from high on Mount Wendelstein in the Bavarian Alps, Germany. Unguided exposure.
Images © the photographers, shown with permission.
Atmospheric
Optics

About - Submit Optics Picture of the Day Galleries Previous Next Today Subscribe to Features on RSS Feed
                    
 
The zodiacal light is a soft cone of light stretching upwards from the horizon after sunset or before dawn when it is sometimes called the 'false dawn'.   It is sunlight scattered by a disk of innumerable dust particles extending outwards in the plane of the Solar System to Jupiter and perhaps beyond.

The light is faint and is best seen in or near the tropics when skies are dark and the ecliptic - where it is concentrated - is strongly inclined to the horizon.

Is there hope of seeing it in more northerly and light polluted Europe? These images show that there is.  

Richard Fleet gives these tips. “The Zodiacal Light is the largest feature in the solar system visible to the naked eye and yet most people have never seen it.  From less developed parts of the world it is all part of the normal pattern of changing light between night and day and is easily taken for granted.  It says a great deal about what we've done to our skies that something so commonplace should be regarded as a challenge for most people.

Time of year and latitude makes a huge difference to how visible it is. Under really favourable conditions it can be surprisingly bright, “False Dawn” isn't a bad name for it and you can tell the dawn is coming hours before the sky gets light.

What really makes it obvious is having a dark horizon so that you see the broader and brighter regions lower down. That shows up well on Chris Brown's earlier OPOD but is completely lost in sky glow on mine. Of course the 60 second exposure shows rather more stars than you would see with the naked eye, but the eye is remarkably good at picking out diffuse glows like this.

This is the best time of year (February/early March) to see it in the evening from the UK or middle to north Europe. Some people think it is only visible around the spring equinox because then the ecliptic is at its steepest, but any time from mid January is good for us. If you leave it until after the equinox the ZL extends into the Milky Way and gets lost.

For early risers the best times for the pre-dawn view are from mid September to late November, before the autumn equinox the Milky Way tends to be a nuisance.

Now the Gegenschein really is a challenge!   I have seen it from Wales and a number of times from Africa. That needs careful planning to choose times when it is high, when there is no moon and there are no bright stars, planets or Milky Way anywhere nearby.



The next sighting opportunities will be from March 2nd when the moon no longer brightens the sky. Look in the south west after sunset and when the sky has fully darkened. Can you find it?