In 1998, Boltwood won the Sky & Telescope magazine Deep Field Challenge. The contest, proposed by professional astronomer Bradley Schaefer, challenged amateur astronomers to take the deepest image of a designed patch of the sky in the constellation Serpens. Using 20 hours of exposure time on his 16-inch telescope and custom software to add the resulting 767 images together, Boltwood achieved a limiting magnitude of 24.1, a result comparable with those seen in professional observatories. His photo was featured as the Astronomy Picture of the Day on April 14, 1999.
