introduction importance of the night sky ambiance of night scenes applications –films, planetarium...

Introduction

• Importance of the night sky

• Ambiance of night scenes

• Applications– Films, planetarium shows,

simulators, games

Sources of Illumination (W/m2)• Sun 103

• Moon 10-3

• Stars 10-8

• Zodiacal light 10-7

• Airglow 10-8

• Cosmic light10-10

• Dim misc. 10 -8 10-9

Model Overview

Moon Position

• ~ 59% of the Moon is visible from the Earth• Rotates around itself at the same speed as around the

Earth• Elliptical orbit

Modeling the Moon

• Geometric model– Albedo map– Elevation map

• Illuminated by– Sun (black body)– Earth (earthshine)

• Specialized BRDF

Data from the Clementine project

BRDF of the Moon

• Low albedo (7%)

• Reddish color

• Backscattering (much brighter at full moon)

• No limb darkening (uniform disc at full moon)

• Constant across the surface

• We decouple BRDF, spectral properties and albedo

Photo by Antonio Cidadao

Low Moon over cityscape

Close-up of rendered stars

Fish-eye view of a clear, moonless night

Time-lapse rendering of stars

Moon and stars over the Little Matterhorn

Moon rising above a mountain

Full Moon with thin layer of clouds

Gibbous Moon

Earthshine

Quarter moon with daylight

Zodiacal light