Did you know that your eyes take about 20 minutes to become adjusted to the dark (known as ‘dark adapted’). Once adapted, your eyes are more sensitive to much dimmer objects, making it easier to see feint stars and deep sky objects (like galaxies and nebulas).
If white light from a normal torch strays into your eyes once you’re dark adapted, it means that you need to wait another 20 minutes to see those feint targets! For nighttime observing, it’s therefore essential to use a red light torch, which preserves your night vision.
Red light torches are available from specialist equipment shops and online, but you can easily make your own. All you need is a torch, two red sweet wrappers (e.g. Quality Street), and a strong elastic band. This works better with a powerful torch, as the beam will still be bright after passing through the red film.
1) Place the two pieces of red film (sweet wrappers) over the end of the torch.
2) Secure them with elastic band.
It couldn’t be simpler!