The phrase "astonishing source" is correct and usable in written English.
It can be used to describe a source of information or inspiration that is surprising or impressive in its quality or impact.
Example: "The researcher cited an astonishing source that revealed new insights into the ancient civilization."
Alternatives: "remarkable source" or "incredible source".
Though I think it's also undeniable that they created something unique and astonishing from their source material.
The Barbican show will explore the astonishing range of source material Basquiat used for his works, from bebop jazz to surreal silent films to trashy TV to 19th-century impressionism.
Even more astonishing is the source of his swelling wealth: an Internet stock.
Over two decades of spying for the Russians, Wise writes, Hanssen "betrayed an astonishing 50 human sources or recruitment targets".
Each month will bring a delivery of single-origin chocolates in an astonishing variety of sources and flavours from around the world.
From short clips off Google's YouTube to movies and TV episodes downloaded from Apple's iTunes store or Amazon's Unbox store to home movies from friends captured on a digital camcorder, and maybe even a bit of illegally pirated footage, consumers are getting their video from an astonishing array of sources.
Notable only for the astonishing longevity of its source material, the film strains to wring humor from slutty bridesmaids and a black priest with Baptist vocal stylings.
The effect on the children of a generation of people whose bricks and mortar, such a treasured thing, became a source of astonishing stress, they became unreal to them, and the money became super-real.
(Laura Kern) 'TONY N' TINA'S WEDDING' (No rating, 1 46) Notable only for the astonishing longevity of its source material, this dated sendup of low-class comportment celebrates the merger of two equally dysfunctional Italian-American families.
