James Roger Prior Angel (born February 7, 1941) is a British-American astrophysicist known for telescope design and the development of spin casting, a technique used to produce mirrors for several of the largest optical telescopes in the world.^[1][2] He is a Regents' Professor of Astronomy and Optical Sciences at the University of Arizona.^[3]

He graduated from St Peter's College, Oxford, with a BA, in 1963, from California Institute of Technology, with an MA in 1966, and from the University of Oxford, with a D Phil, in 1967.^[1]

He has taught at Columbia University. He is a Fellow of the Royal Society. He was elected a Fellow of the American Academy of Arts and Sciences in 1990.^[4]

In 1979, he proposed the lobster-eye optics principle for X-rays.^[5]

In 2006, Angel proposed assembling a space sunshade to mitigate global warming by placing trillions of 0.6-meter, 1-gram disks of refractive material into stable orbit between the Earth and the Sun (Lagrange point 1, or L₁). The disks would be launched in stacks of 800,000 by electromagnetic acceleration and transported to L₁ (1.5 Gm from Earth) via ion propulsion. After separation the individual disks would remain in place by autonomously modulating solar radiation pressure. Together the cloud of disks would deflect 2% of solar radiation onto the Earth, enough to counteract the warming effect of a 100% increase in atmospheric carbon dioxide from pre-industrial levels. He concluded that such a sunshield "could be developed and deployed in ≈25 years at a cost of a few trillion dollars, <0.5% of world gross domestic product (GDP) over that time."^[6]

On August 23, 2012, Angel and his inventions were the subject of a story on NPR's Morning Edition.^[7]

• 1976 Newton Lacy Pierce Prize in Astronomy
• 1996 MacArthur Fellows Program^[8]
• 2010 Kavli Prize for Astrophysics
• 2016 National Inventors Hall of Fame^[9]