"deep sky" is a valid phrase in written English.
You can use it to refer to the sky as seen from earth. For example, "The stars in the deep sky shone brightly."
"A lot of what we look for is deep sky objects.
The result was typical of the designer: upbeat colors like deep sky blue and burning-sun yellow.
Brady Haran, the producer of the Deep Sky astronomy videos and Numberphile math videos, will develop two of the channels.
I spent a week roaming the observatory and visiting most of the telescopes for the Deep Sky Videos series.
Complicated antirrhinums, yellow-lipped, salmon mixed with pale brick-red, deepest maroon, stand against a deep sky blue.
Occasionally, however, heads turn and conversation pauses as a deep sky blue 1975 Corvette pulls in, driven by the state's usually buttoned-up attorney general, Andrew M. Cuomo.
He all but apologized for his own ride — a deep sky-blue 1975 model that he bought for $4,750 while in college — saying it was nothing compared with most at the show.
ISO's program included both solar-system and deep-sky objects.
Like other apps, you can filter the view in other respects, to show only constellations or deep-sky objects.
(Another Zooniverse project, Galaxy Zoo, has enabled more than 600,000 amateur astronomers to help with classifying an immense number of deep-sky objects since 2007).
It conducted a photometric deep-sky survey in the ecliptic plane for part of the mission and then collected spectroscopic observations in the final phase of the mission.
