Setting a Red Computer Display to Preserve Night Vision in Linux

August 10th, 2014

Astrophotography sometimes requires the use of the computer screen whilst operating the telescope. This is damaging to night vision. It is better to use a red screen.

Linux users can install the program “xcalib”. For systems that use the Apt package manager (such as Ubuntu), xcalib can be installed with the command:

sudo apt-get install xcalib

The green and blue components of the display can then be switched off with the commands:

xcalib -green .1 0 1 -alter

for green, and

xcalib -blue .1 0 1 -alter

for blue. The display will now be red. The display can be reset with:

xcalib -clear

These commands can be added as aliases. If the bash shell is being used (it probably is, this is the default for Ubuntu and Mint) the following lines can be added to the .bashrc file (note the full stop).

alias astro=”xcalib -green .1 0 1 -alter;xcalib -blue .1 0 1 -alter”
alias notastro=”xcalib -clear”

The .bashrc  file needs to be in the /home/[username] directory, and may not exist so you might need to create it.

The display can now be set to red with the command “astro” and reset with “notastro” at the command line.

Alternatively, these commands could be added to a shell script and kept on the desktop where they can be run with a mouse click.

Don’t forget that the brightness control still works…

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