Amateur Astronomers Help Professionals Unveil The Atmosphere Of Venus

Silvia Kowollik, from the Zollern-Alb Observatory in Germany and one of the participants in the project, said, "This is the first time there’s been a European collaboration between amateur astronomers and scientists. In the United States, they have a long tradition and a lot of experience in this kind of work. In Europe we are just starting."

Since its launch in 2006, ESA’s Venus Amateur Observing Project (VAOP) has invited amateur astronomers to submit scientifically useful images and data to support scientists working on the Venus Express mission. The amateur images, taken in the infrared, visible and ultraviolet bands, give a different, global perspective on features observed by the spacecraft, show a comparative view of the planet in various parts of the spectrum covered by instruments aboard Venus Express, and can also capture views of Venus that are hidden to the spacecraft in its orbit. The highly elliptical orbit of Venus Express means that the spacecraft moves slowly around the planet’s south pole but whips over the northern latitudes, so the ground-based images are especially important for observing features north of the equator.

Dr Thomas Widemann, who is participating in a parallel professional campaign of ground-based observations to support Venus Express said, "There have been huge advances in relatively cheaply available equipment, which means that amateurs can take images in wavelengths from infrared through to ultraviolet with impressive accuracy and content. These amateur observations are the last link in a chain that starts with Venus Express and continues with the professional ground-based activities. When joined together, all these observations will all help to peel back the atmosphere of Venus and reveal her mysteries."

Developments in video astronomy have meant that amateurs can select and combine thousands of rapidly exposed video frames in order to cancel out the distorting effects of atmospheric turbulence.

Ms Kowollik said, "This has been a great experience for amateurs. Several observers in Germany have taken part and have gained considerable expertise in image processing. We are now looking forward to future Venus observation campaigns."

The ultraviolet observations are of particular interest because scientists still do not know the chemical constituent of Venus’s atmosphere that causes the planet’s yellowish tinge. Dr Widemann said, "Something is absorbing the blue end of the visible spectrum. There are many theories – it could be material derived from meteorites that contains iron, it could be molecules of carbon monoxide dissolved in sulphuric acid droplets, or molecules made of several sulphur atoms. Perhaps it’s a combination of all of these. The amateur ultraviolet observations may assist in this investigation. To know for sure, we need measurements taken within the Venusian atmosphere, perhaps by instruments carried by a balloon."

"The next ground-based observing campaign will begin in September, when Venus increases its angular distance to the Sun in the morning sky", Dr Widemann said, "By participating in the VAOP, amateurs can receive proper recognition for their skill from the professional community. It should be a great boost for amateurs across Europe and will give them a just reward for their enthusiasm.