Chemical Wedding, a software design and development company, has announced the availability of Helios, a professional-quality sun position calculator for the iPhone and iPod touch. Using code from the National Renewable Energy Laboratory, Helios enables users to pinpoint exactly where the sun will be at any particular time and location, accurate to within a tiny fraction of a degree.
Helios is aimed at a broad market of professionals including those involved in cinematography, stills photography, architecture, urban planning, landscape gardening and solar panel installation – who need to know the position of the sun and the shadows it casts in order to do their jobs. Helios costs $29.99 (18) and is available exclusively through the Apple iTunes store.
As the iPhone rapidly becomes the smart mobile device of choice, particularly within the creative industries, we believe that people will increasingly want to use their phones for work as well as play, said Toby Evetts, director at Chemical Wedding. Helios has been developed and designed for a professional audience and is a good deal more sophisticated than the average iPhone app. $29.99 may seem relatively expensive for software on a phone, but depending on the business, Helios replaces kit worth up to $300.
Initially developed for the film industry, Helios is already in use by movie professionals including Russell Carpenter, the Oscar-winning Director of Photography on 'Titanic', and Seamus McGarvey, the Oscar-nominated Director of Photography on 'Atonement'.  
If youre a cinematographer or stills photographer shooting in natural light, its essential you know how the light is going to change throughout the day, says Nic Sadler, a Partner in Chemical Wedding and a Cinematographer for the past 20 years. And while an enormous amount of preparation goes into exterior location filming, decisions are often made on the fly about the exact set-up and location of shots. As such, its essential to have sun position information available in a fast and easy to use, mobile format.
Helios works with all versions of the iPhone and iPod touch, incorporating new features as they are added. For example, iPhone 3GS users can use the internal compass feature to show the exact sun position from their location, and use the devices accelerometer as a pocket inclinometer to pinpoint the suns elevation, and thus plan shoots without the need for a separate inclinometer and compass kit.
Theres a video explaining how Helios works here.