An attempt to view the Ashen light was made in Hawaii using the Keck 1 telescope. Researchers claimed to see a faint green glow on the night side of Venus. They suspected that is was carbon dioxide which is known be of a high concentration in that atmosphere. When the molecules are split by the ultraviolet light from the Sun, they become carbon monoxide and oxygen, which emits a green light. However, this light emitted is very faint, and researchers doubt that it is the explanation surrounding Ashen Light.
Amateur astronomers attempting to view the Ashen Light can try it by using an occulting bar, an opaque mask for one’s eyes. This lens blocks the sunlit portion of Venus which greatly cuts down extraneous light that is scattered in the eye, improving the chances of witnessing the faint Ashen glow. However, Venus light scattered by the Earth's atmosphere and in the telescope's lens still works against the observer, and it is very hard to get the timing just right. Nevertheless, there have been calculated times in which the light scattered by Earth is covered partially by our Moon. For example, on July 17 2001, the progression of a crescent Moon temporarily hid the illuminated portion of Venus. Unfortunately the location needed to catch this almost perfect occultation was somewhere in the middle of the Atlantic Ocean, and it was only visible in this manner for 10 to 20 seconds.
The fact that many totally independent observers have observed the Ashen Light simultaneously, that some of these simultaneous observations were made by professional astronomers and that the observations persist today with improved instrumentation suggest the phenomenon is real.
In a pictorial representation,
Inferior vs. superior conjunctionAssuming that the location and the ability to observe the Ashen Light is in our favor, meaning we do not have to be in the middle of the ocean with technical instruments that allow us to view it without damage done to the eyes, Russell and Phillips found that it is possible to replicate the common characteristics of the sightings measured in the figure above. A more detailed explanation can be found in the paper itself for those interested in the mathematics of it.
Taking into consideration the limited amount of observation and the “simplicity of the model”, according to Russell and Phillips, the relation between observed sightings and the calculation seems to bring more promise in finding out the true cause of Ashen light. It supports the hypothesis that the source of Ashen Light occurs mostly on the night side of Venus. The distance from the Earth to Venus could be a factor that controls the visibility of the light, however it also has to do with the observer’s specific location.
- Gingrich, M.; Myers, E. "The Paradoxical Ashen Light of Venus". Bulletin 77 (7):