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:
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…
July 27th, 2014
I've been doing a little bit of web design the last few weeks.
It appears that css style sheets do not natively support the definition of variables and the ability to perform basic addition/subtraction operations. This would be helpful when an element is resized and other page elements must be resized appropriately, or when the colour of an element is defined as a different shade of the colour of an adjacent element where a hex value can be simply added or subtracted Read More...
July 27th, 2014
I've been having problems with the RA setting circle on my Skywatcher EQ5 mount.
The RA setting circle is a collar that slides onto the RA axis with a surrounding fixed sleeve that extends down to the scale on the circle. As the mount rotated along the RA axis I was finding the RA circle had a tendency to slip Read More...
January 1st, 2014
Recently, I was doing research online to select a new telescope. This has since been purchased, but I am still being bombarded by adverts for telescopes. Clearing my cookies has helped, but my browsing history appears to be linked to my IP address and browser request header. I find this to be a continuing source of annoyance Read More...
August 3rd, 2013
The substrate of an aquarium is the gravel at the bottom of the tank. The choice of substrate is important. Things to consider are:
Colour: The colour of the substrate changes how some species of fish or invertebrate behave. The popular cherry shrimp changes colour depending on the colour of the gravel Read More...
January 19th, 2013
I have previously blogged about difficulties with Linux and the Fujitsu-Siemens V5535 laptop. This is now an old laptop, and hardware support is now a lot better in Linux.
I have recently installed Lunux Mint.
Everything works following a default installation, without the need for any custom configuration.
January 13th, 2013
Periodically my phone gets *really* hot and my battery drains quickly.
I have wasted a tremendous amount of time troubleshooting. I've cleared RAM, killed background tasks and uninstalled lots of apps.
August 13th, 2012
Whenever I get into a discussion about the importance of strong passwords, the response I am invariably "challenged" with generally goes as follows:
I am an obscure and unimportant individual. I am not famous. I do not have any political connections. I do not hold any sensitive information online Read More...
June 13th, 2012
For most people, the water from the kitchen tap is mostly OK for a typical fish tank. However, water quality can vary greatly, even within the same county. This is one of the advantages of finding an experienced aquarist in your area - for most people this will be a local dealer. They will advise on the suitability of your local water Read More...