by Tony Wallace, HAA Observing Director, December 1997
Winter is one of my favourite seasons. No, I'm not deranged, but, I've learned to harmonize rather than fight with the weather it brings. I've spent many a weekend winter camping and enjoyed it thoroughly, day and night, even in temperatures of -35C.
The learning came at the cost of numbness, shivers, and generally living my mistakes in the early boldness of these ventures. Last winter I was able to confirm that the same techniques that warmed me on trail and in camp would keep me cozy at the eyepiece of my telescope.
Here, then, is some of what I now know about dressing for comfort as applied to winter observing.
How warmly should I dress?
Observing consists mostly of sitting or standing around as opposed to walking, chopping wood etc. Add to this the effects of radiating our heat into the inky night sky and you have a recipe for disappointment. The cure is simple. We need, only, to dress somewhat warmer than if we were outside doing some physical activity.
In order to be comfortable we need to dress for a temperature of about 10 degrees lower than the air temperature. This, by the way, is good advice for observing at any time of year, but, particularly so in winter.
Know Thine Enemy!
Rather than provide you with a list of solutions, I would like to explain some of the processes at work as we try to keep warm and the basic remedies for these. Once you understand what's happening, you become able to recognize symptoms and devise your own solutions to problems that may arise while you're outside on a winter's night.
The major culprit in making us feel cold is our perspiration. We're all familiar with the perspiration of summer, but, what about other times? It may surprise you to know that we perspire continually, all year round, all day long. It seems our skin is very partial to life in a tropical rainforest and tries to create these humid conditions wherever it may be. In fact our comfort demands these conditions. Skin LOVES moist air and sets about making this environment by perspiring into the adjacent atmosphere. This emerges from our pores as water vapour. We are generally unaware of this process and only feel a change when this forms on the skin as a film of water and then evaporates directly from the skin's surface. In this case, the perspiration is being used to cool us down rather than just avoiding dryness.
The process of evaporation, you may recall from high school physics, requires an additional bolt of heat ( Latent Heat of Evaporation?) to go from a liquid to its gaseous state. It gets that heat from the skin's surface, thus, cooling us down in the bargain. But, we don't WANT to cool down on cold winter nights! So we put some clothing next to our skin and feel warmer. OK?… Maybe…
It depends on what that undergarment is made of. The most popular fabric for underclothes is cotton. We like its soft feel, it's inexpensive, and it's durable. Problem is, it's just about the worst thing one could wear next to the skin on a cold night! You see cotton likes water. That is to say, cotton absorbs and retains water, which is why we use it in the best towels. One reason it feels so nice, is that it's much easier to have a rain forest next to your skin when what you're wearing is sopping wet! So, getting back to our skin, cotton soaks up the water and holds it by the jugfull. Then, in order to stay warm, we not only have to keep ourselves warm, but, also that wet garment must be kept warm too! What we need is a fabric which abhors and detests water and would rather dump it out than retain it. Polypropylene is the best known of these "anhydrous" fabrics. It's a bit more expensive than cotton and you've got to be careful to wash it in cold water and hang to dry. Otherwise you'll be lucky if it'll fit the cat after a good hot wash & dry. We refer to such fabrics as having the ability to "wick" the water away. And that is just what happens. The perspiration is conducted away from the skin, often before it can even condense. Condensation, if it occurs at all, takes place on the outside surface of the garment all undetected by our lily whites and we feel warm. Kewel!!
The Layered Look…
Layer 1: winter lingerie
We have seen how important it is to choose the right kind of undergarment fabric for staying warm in winter. The undergarment is part of a system of "layers" designed to maximize our heat retention and stay cozy while at the eyepiece or some other activity. This garment ought to be snug fitting. Let's refer to this as Layer 1.
Layer 2: the Fluffies
Next, comes the insulation layer. This, as the name states, is to insulate us from the cold of night. Garments are better to be loose fitting than tight. Appropriate fabrics are characteristically bulky, lightweight, and able to trap still air in its tangled fibres or "tiny air pockets".; air movement being a "no-no" for heat retention. Roughly speaking, they can be divided into 2 piles… natural and synthetic. Each of these have pros and cons.
The most popular natural ones are down and wool. Down is "nature's own snuggly blanket" and the most efficient insulator for our purposes. High grade goose down is able to provide more insulation value per unit weight AND per unit volume than any other material for this application. It has, however, one serious drawback. If it ever gets damp or wet (God forbid!) you've got BIG TROUBLE! It takes days to dry out and it's insulating value plummets to uselessness in this state. Down is definitely NOT anhydrous. Remember the perspiration that passes through Layer 1? If it collects in Layer 2 (and it will!) you're in for discomfort. Down is beautiful stuff and a great temptation, but, I've come to avoid it in clothing for this very reason. Well… that, and the fact that they want my firstborn for it!
Wool, on the other hand, is relatively affordable, and, while not having as high an insulation value as down, it does a pretty good job in clothing. Hey! One can always get two sweaters on… Right? More about this later…
What about dampness? Wool has the wonderful quality of retaining much of its insulation value even when its wet! It is much more forgiving than down. Think of it as having built-in insurance. I like it. My skin doesn't!! Many, like me, have skin that rebels against dressing up like sheep. We either put up with the itching, tickling, and general torture, or, find something else…
Enter the synthetics. There are now quite a lot of great synthetic fabrics with excellent insulation qualities on the market. Names like Hollofil, Quallofil, and Thinsulate come to mind. They're all anhydrous and a good choice for Layer 2. My favourite, though, is Polartec by Malden Mills. This stuff is very lightweight, has a luxurious fluffy feel to it, doesn't "pill" (form little balls of fabric on the surface after repeated use; aka 'nubblies'), and comes in an endless array of colours and patterns. It is so anhydrous, that if you, get it completely soaked, just squeeze out the water, and it'll hang dry in 20 minutes. It will even dry while you're wearing it! I had the privilege of confirming this empirically on a Fall canoe trip once. But that's another story…
OK! There you have it. Some Layer 2 facts and personal biases. The last thing to remember about Layer 2 is that it is far better to wear multiple thin layers than a single thick one. The wisdom in this is as follows… If you are warm to the point that you are feeling perspiration, then, you can (must?) peel a layer or two until your brain turns off the water tap. If not, you continue to push moisture through Layer 2 at a high rate. Even the best will have trouble keeping up with this and leave you with a jacket full of water to keep warm. So… Layer 2 is actually as many thin layers of insulation as you will need for the coldest temperature of the night in question minus 10 degrees C. Remember the additional -10 degree rule of thumb?
Layer 3: the Wrapper
Layer 3 is an outer shell with 2 important functions. It has to keep the wind and rain from getting to you, and, it has to pass the moisture that's been travelling out through Layers 1 & 2 from your skin. Now, we don't do much observing in the rain, so that's not a concern here, but, keep it in mind for other outings when buying.
Wind? We don't observe in the wind! Even the slightest of breezes will meander through Layers 1 & 2 and kiss you with frozen lips. We need to keep that air movement, however small, outside Layer 3! At the same time, Layer 3 must allow our inner moisture free access to the universe. These two requirements may seem to be mutually exclusive in a single garment. Not any more!
There are a number of high-tech synthetic fabrics now that can do just this. The best known of these is undoubtedly Gore-Tex. Gore-Tex is as waterproof as a rubber glove, yet will allow water vapour or air to pass through the "micropores" in its waterproof barrier. If absolute waterproofing is not a biggie for you, then, consider a fabric known as Super Microft. It is what the manufacturer calls "water repellent". My experience with this has been that it'll keep you dry long enough to get to shelter… if you run! I like it because it's an excellent wind barrier, lightweight, soft and comfortable, and, above all, it's a good "breather" that'll vent my own moisture to the world outside. Get them a size bigger than you normally would and they'll be perfect at the eyepiece or any other cold outing These specialty fabrics, and consequently, the garments, are a bit pricey. But, consider the following…
I have two shells: one in Gore-Tex, the other is Super Microft. My last Gore-Tex jacket is 10 years old and still going strong. (I grew out of it!) I don't own or need a raincoat, overcoat, leather coat, parka, snowmobile suit, Fall or Spring jacket, K-way shell, or umbrella. I've avoided a lot of purchases over the years… Hmmm? These two are functionally superior and look good too. Well… at least to those who know the magic they hold!
In part 2 we'll look at keeping your hands, feet, and head cozy and comfortable along with a few goodies for a beautiful winter night's observing…
