> LED back light screens flicker research
Most of the modern LED backlight screens including Laptops, TV and smart phones use PAM technique for Pulse-amplitude modulation. This means that they switch on and off state very rapidly.
This is implemented to save energy and control the back light brightness, but it is harmful to the human nervous system and case eye strain.
I have tested some devices with photographic method by taking a shot of 1/8000 of the second. Each on and off transit state will produce a dark line in the shot. On the picture below is Samsung galaxy s3 that has a very poor performance. You can measure the on/off state frequency by counting the dark lines. A good display should has no lines on the shot. This will produce the comfortable frequency of above 4000Hz.
The flicker increase by reducing the screen brittleness. But using appropriate screen birthrates is important for eye comfort when staying at night in front of the computer.
You can easily test if your screen is good with a pen. Wave the pan in front of the screen. If you see a blued image, it is ok. If you see a scattered image then the flicker frequency is too low and your eye could see it.
If you have already such a bad device, you can use a software to reduce the brittleness that will actually twerk thee tone instead of the display back light. Such is Twilight for smartphone or flux for PC. Those apps also can make the screen warmer as the violet-blue light is most harmful for the eye. For Win 10 and latest Mac OS there is also embalmed functionality to make the screen tone warmer.
Here is my Samsung Galaxy S3 screen with 1/8000 of a second exposure:
Nowadays we are so into the globalization and technologies, that I can submit observation plan to a remote, professional observatory at the other part of the word!
This is a comparison of my not modified Pentax k5 DSLR and the same, but modified one without IR-cut filter.
Astrotracer is a great way to take advantage of the Pentax DSLR camera in-body shake reduction mechanism. It is available since Pentax k5 and track celestial bodies by moving the sensor. Here is what is it ablout:
Staying at my home inspires me to make some documentation of my experience. I got a dedicated drive for my astrophotos and start reorganize them by objects. Here is an article of the most recent process I use on my photos. Enjoy: )
For a few months from now Betelgeuse (Alpha Orion) dim so much, that it looks as bright as the stars in the Orion belt. This is not so disturbing and does not mean that cataclysmic events are happening with it.