Astrophotographer spends 12 years making 1.7 gigapixel Milky Way photo

A Finnish astrophotographer has published a composite mosaic image of the Milky Way with a resolution of 1.7 gigapixels. It took him almost twelve years to create this high-resolution photo.

On an astrophotography blog, JP Metsavainio has published his photo and all kinds of individual shots. The total shutter speed was approximately 1250 hours and the photos were taken between 2009 and 2021. The final merged photo is 100,000 pixels wide and is made up of 234 individual mosaics or panels, which are then stitched together. This is a technique often used for panoramas, including astrophotography.

Some subjects had slower shutter speeds than others, otherwise it was difficult to capture very dark subjects well. The colors come from the different elements, where green stands for hydrogen, red for sulfur and blue for oxygen. About twenty million stars are visible in the photo with the final result.

There are a number of reasons why Metsavainio has taken so long on this project. The size of the photo is the most obvious reason. But another reason is the fact that he first considered the individual elements in the photo as individual compositions and wanted to publish them as independent works of art. “That led to a complex image set with overlaps, with many areas between and around the frames not being photographed,” he says. He later shot the missing data. This mainly concerns the less interesting parts that do not contain nebulae, such as the California Nebula.

Reduced view of the final result

Metsavainio used the necessary equipment to get the picture and the stuff also changed over the years. Until 2014, for example, he used a Meade LX200 GPS 12″ telescope in combination with a QHY9 astro camera and a Canon EF 200mm f/1.8 lens. After 2014, this was exchanged for another combination. He used his own observatory for the shots. and the post-processing, such as connecting the mosaics, he did with Photoshop.

The 234 different panels that have been put together for the final result