As a prelude to my post on head torches (and the Petzl Tikkina in particular), I asked @ukjeeper, a regular night time countryside walker (and Social Hiker), to write a post on walking at night, why he enjoys it, and any hints and tips he has. Here is what he has to say:
With the days drawing short, most people’s only option for walking, during the week at least, is going to be in the dark.
Personally I enjoy it. The world at night has a completely different feel to it. Familiar walks can often appear to be quite different when the sun has gone down. Different viewpoints, smells and often wildlife are experienced during the twilight hours. Once you are practised and experienced at walking in the dark, it actually becomes quite easy. Paths are usually easy to find and follow as the dark line on the ground is visibly clearer than the surrounding area.
I am fortunate enough to have good night vision, only having to resort to using a torch on moonless nights or when under tree cover. Perhaps I have particularly efficient ‘rods’ in my eyes. I’m not referring to a horrible industrial accident or some form of cybernetic upgrade, the human eye retina is composed of ‘cone’ and ‘rod’ cells. Cone cells are used for seeing colour and brighter light environments, rods are designed for black and white and low light environments (ie, the dark).
Molecules of rhodopsin in the rods of the eye undergo a change in shape as they absorb light. Rhodopsin is the chemical that allows night-vision, and is extremely sensitive to light. Exposed to a spectrum of light, the pigment immediately bleaches, and it takes about 30 minutes to regenerate fully, but most of the adaptation occurs within the first five or ten minutes in the dark. Rhodopsin in the human rods is less sensitive to the longer red wavelengths of light, so many people use red light to help preserve night vision as it only slowly depletes the eye’s rhodopsin stores in the rods and instead is viewed by the cones.
Rod cells are also more sensitive to movement. A useful tip when trying to focus in on an object in low light is NOT to stare at the object directly, but use peripheral vision as this uses more of the rods. Look slightly away from the object and move your eyes.
Although the cones and rods work together, it can take a while for your eyes to adjust to the lower light, which can take as much as 20-30 minutes. Before starting off, try as much as possible to allow for your eyes to adjust. It would be embarrassing to fall into a ditch 10 feet from the car (yes, I’ve done it). While out walking, also try to avoid looking directly into artificial light. Halogen floodlights and car headlights are great for the owners, but reset your retinas back to ‘day view’.
As I prefer to walk in the dark as much as possible rather than walking along like an illuminated Cyclops with a head torch, I carry a small, but strong LED torch in my pocket, covering the lens to only emit as much light as I need for the situation. Another option is coloured filters that fit over your torch lens. Just be aware that some, especially red, the most popular filter, will ‘filter’ out the colour red. A colour often used in OS maps. You might not see an important symbol or contour line. Some people prefer to use a blue filter instead.
With the absence of identifiable features and landmarks at night, make even more sure than usual you know where you are on the map and where you intend to go. Its incredibly easy to get lost at night, and often harder to get oriented again.
For those that are lucky enough to have electronic mapping solutions (EG; Viewranger) turn the brightness down as much as possible while still being able to see the display. On more than a few occasions I’ve been blinded by a 7” LCD screen while checking my position. The Symbian version of Viewranger has a ‘night vision’ setting. If you have it, use it.
Also, look in the app market (smartphones and tablets) as there are often (depending on your model) apps that turn your camera LED light into an emergency torch. A useful item to have if your torch happens to die when you least expect it.
Some even have an SOS option, useful if you end up in the unfortunate position of having to be rescued. That little light can be seen for a very long way.
While on the subject of mobile phones and summoning help, it is even more important to leave word of where you’re going and when you should be expected back. If you have a tracking system (such as Viewranger, Instamapper, SPOT, etc) use it, and make sure someone else knows how to look you up if needed.
Searching for a lost soul will take even longer in the dark, and its generally colder (and damper) at night so a quick recovery is a good idea.
Guest post by Tim Cooper – @ukjeeper on Twitter
Thanks Tim for an interesting and useful post!