antisolar
adjective
an·ti·so·lar 
ˌan-tē-ˈsō-lər,
ˌan-ˌtī- : being or having a direction away from the sun
the antisolar point
Example Sentences
Recent Examples on the Web Rainbows always form 42 degrees outward from the antisolar point because of how raindrops refract, or bend, sunlight. 
Washington Post, 18 Aug. 2020 Lobby power: Indiana legislators received thousands in gifts while pushing antisolar policy. Emily Hopkins, Indianapolis Star, 26 Mar. 2018 The tail of the comet always points straight away from the sun, in antisolar direction. Donna Vickroy, Daily Southtown, 2 Nov. 2017
Washington Post, 18 Aug. 2020 Lobby power: Indiana legislators received thousands in gifts while pushing antisolar policy. Emily Hopkins, Indianapolis Star, 26 Mar. 2018 The tail of the comet always points straight away from the sun, in antisolar direction. Donna Vickroy, Daily Southtown, 2 Nov. 2017 Word History
First Known Use
1842, in the meaning defined above