Celestron Night Vision Red LED Flashlight.

This straightforward red-light torch uses a 9V battery to power a pair of red LEDs, turned on via a rotary switch that also controls brightness. The red light can be dimmed for reading maps and star charts or made brighter to navigate around a dark-sky site. At only 14 pounds, this is genuinely one of the most useful things you can own as a stargazer on any budget.

Here's why: White light destroys rhodopsin almost instantly, undoing 30 minutes of dark adaptation with just one exposure, but red light doesn't affect rhodopsin, so you can use it whilst still maintaining your dark adaptation. It's the difference between reading your star chart and ruining an entire evening's observing. You'll be using this torch at every session, not just occasionally.

This is a highly recommended torch in a simple design that fits nicely in the hand and also features a thin wrist strap, and is similar to the Orion Red Beam II LED Torch. The build is standard plastic, but the dimensions and weight (3.5oz with battery) mean it's easy to carry, though it may not last as long as premium metal alternatives. The square shape is practical - it won't roll off your observing table on a windy night.

Before you buy, check you've got a 9V battery (one is included). The torch needs very little space to store. There's no minimum sky darkness required - red light works anywhere from suburban gardens to proper dark-sky sites. One thing to note: on low mode the battery runs for about 300 hours, and on high mode for 12 hours, with an easy-to-use thumbwheel for brightness adjustment. This is your first line of night-vision defence, and at this price, there's genuinely no reason not to have one.