The Helix Nebula is a trillion-mile-long cloud of hot gases.” At its center is dying star which has ejected masses of dust and gas to form tentacle-like filaments stretching toward an outer rim composed of the same material. Our own sun may look like this in several billion years.
The Hubble Space Telescope has 5 cameras on it but not one of them recorde the colors of visible light that we see in this image. All visible light images are in the grayscale.
- (WFC3) - The Wide Field Camera 3 sees three different kinds of light: near-ultraviolet, visible and near-infrared.
- (COS) - The Cosmic Origins Spectrograph is a spectrograph that sees exclusively in ultraviolet light.
- (ACS) - The Advanced Camera for Surveys sees visible light, and is designed to study some of the earliest activity in the universe.
- (STIS) - The Space Telescope Imaging Spectrograph is a spectrograph that sees ultraviolet, visible and near-infrared light.
- (NICMOS) - The Near Infrared Camera and Multi-Object Spectrometer is Hubble's heat sensor.
So one might ask how does NASA end up with color images of deep space objects like the Helix Nebula? The finished color images are the work of NASA photo imaging specialists adding color to the image. The colors are assigned to represent various makeup of the nebula. The color enables us to visualize the gas and dust that is not visible to the human eye.