When I take my laptop outdoors in the night for astronomical observations, I tend use use a lot of Astropy scripts. But the sheer brightness and the color-scheme is messing with my vision in the night. Simply lowering the brightness of the screen only helps partially.

So I found out - quite in fact already years ago, and I do not even recall the original source - how to set your screen to monochrome in a red on black color scheme.

For this I use the xcalib for Xorg program, which should be part of every Linux distribution.

To enable red-on-black monochrome, start a shell and start:

xcalib -green .1 0 1 -blue .1 0 1 -red 0.5 1 40 -alter

To go back to the usual mode, simply start:

xcalib -clear

I suggest to set up two aliases for quickly changing, such as:

alias goclear='xcalib -clear'
alias gored='xcalib -green .1 0 1 -blue .1 0 1 -red 0.5 1 40 -alter'