Although our annual winter observing session is called, "Freeze Your Bun's"; the best plan would be to actually avoid freezing any body parts, while having a fun and productive adventure under the stars.

Everybody has more than likely heard comments about dressing in layers, but how many of you understand why you should dress in this fashion.

The first reason to layer your clothing is to trap dead air in between the layers of clothing. It is this trapped air that really makes insulation work, exactly the same insulative process as the dead the air trapped in between the fiberglass insulated walls in your home or foam insulated coolers you use to keep your food and drinks cool.

The second reason to dress in layers is to have an effective and easy way to control your body temperature. How many of you go out into the cold with a heavy expedition type jacket and pants like Nannook of the North, only to start sweating as soon as you start to set up your equipment. Sweating is a natural body function that cools you and helps you maintain a comfortable and healthy body temperature. Sweating or perspiring is an involuntary bodily function that takes place even when you are not doing strenuous work but it can be a real enemy to anybody outside in the sub-freezing night.

Layering your clothing allows you to take off or put clothing on as your activity changes. Of course you will add more clothing as you settle in to do some serious observing and you will again take layers off as you increase your activity. How many times have you been all dressed up while running back and forth between your scope and car white setting up and started to perspire, only to feel chilled within minutes after you settle down to start observing. Use your layered clothing to control your body temperature and avoid becoming too sweated.

Wind gear can be important at keeping warm air trapped inside your clothing. Wind gear can be any type of outer garment that blocks the flow of cold air into your insulative dead air space. The one exception is rain gear that does not allow moisture to escape to the outside often-trapping excess moisture inside your clothing to a point that your layering becomes wet and ineffectual.

Hands and feet always seem to be the parts of our bodies that sense the cold first. If you think about it, your hands and feet are furthest from the core of your body where your metabolic bodily function creates heat and then your heart pumps warmed blood to all parts of your body. Another natural and involuntary body function occurs when your system restricts or stops sending warmed blood to your extremities as your core temperature drops. But sometimes no matter how warm you dress your main trunk area, your feet and hands still get cold. Many times this is because you leave your head and neck uncovered. Your head and neck area has the largest surface area of blood vessels and arteries near the skin's surface and because of this it is the largest extremity of your body where you can loose the most body heat. Many times just putting on a warmer hat or hood can take the chill off the tips of fingers and toes.

When it comes to hands and feet, the same rules of physics relating to insulation applies. Often times gloves don’t create enough dead air to keep the hands warm, but mittens in the way they envelope your hand with their increased effective dead air space helps keep hands warmer. Mittens can be a pain to use because your fingers are not free to work the controls of your scope or turn the pages of your charts. There are two easy answers to this dilemma. The first is to buy a pair of mittens that have a flap that opens to expose your fingers when needed and then re-closes to re-warm your quickly chilled fingers. Some of these mittens can hold a small hand warmer inside the flap that will quickly warm your fingers when closed. Another answer is to wear mitten shells over top of your gloved hand. Mitten shells are usually wind or water proof nylon shells that climbers and hikers use to keep their gloves and hands dry. With the increased dead air space inside the mitten shell your gloved hands should feel much warmer.

Before discussing your feet, I want to caution you on wearing too many layers that can become tight and restrictive to a point where they could lessen the effective dead air space or even worse cut off or restrict the flow of blood to your feet or hands. Again without the warming flow of blood throughout your body, there won't be any heat for all insulation in the world to trap heat near your body to keep you warm.

I think everybody will agree that the hardest part of your body to keep warm is your feet. Again layering is very important here, but you have to be careful when it comes to circulation and perspiration. The one part of your body that seems to sweat the most would be your feet; surprisingly they sweat even when they are cold.

This is where we will start talking about the different fabrics that arc available and what is good next to your skin and what is not. It does not matter what part of your body you are trying to cover and warm, cotton next to our skin is not recommended for winter usage. Cotton is great at wicking up moisture from your skin or even your breath, but it is terrible at releasing this moisture into the next layer of clothing. Synthetics or wool are best for wicking and releasing moisture. Again the idea is to wick away the moisture away from the skin and into the outer layers of your clothing and eventually into the outside air.

There are many kinds of miracle fabrics out there today that boast at being the best at wicking moisture away from your body, but after many years of winter hiking and ice climbing I haven't found anything better that just plain wool. Already you are starting to itch and squirm but don't fret, there are many wool blends available that don't itch. Unfortunately many of these blends are expensive and hard to find. For those budget minded astronomers out there, there is a cheaper alternative in Polypropylene long underwear available in different weights and thickness'. Polypropylene is great at letting moisture pass through to the outer layers of clothing and staying dry or drying quickly when soaked.

Now lets get back to our feet. How do we keep our feet warm? First and foremost, keep the blood flowing. Don't try jamming 2 or 3 layers of socks into your heavy winter boots because you are going to cut the circulation off. Buy your winter boots large enough to allow for extra layers of socks, leaving plenty of room to wiggle and not jamb your toes when you have the boot and sock combination on. Again, without the flow of warm blood into those piggies, even your minus 60 degree rated boots won't have any heat to hold in.

Next thing we don't want to do is wear cotton socks under wool socks. The cotton socks will hold moisture close to your skin and your feet will always feel cold and damp. Wear wool or one of the synthetic blends next to your skin. Remember that happy feet are dry feet.

For those of us who are getting up in the years and the flow of blood always seem restricted, there are chemical and battery warming devices out there that work very well. The only cautions are that you have room to put these devices inside your garments without restricting blood flow and make sure there is no chance of chemical burns or electrical shock from the devices.

Now lets review...

• Dress in layers to trap insulating air and control our body temperatures.
• Wear warm headgear that covers both your head and neck area.
• Combinations of gloves and or mittens/shells plus hand warmers work well to keep you hands warm.
• Do not restrict blood flow; wear loose fitting clothing and boots. Felt lined boots have become the standard winter foot gear in New England, but even those do not work well when they fit too tight.
• Do not wear cotton next to your skin, in fact make it a practice to stay away from cottons all together when spending long periods of time outside in the winter.
• Breathable wind-gear helps maintain the dead air space inside your clothing.

One more thing worth mentioning. When you get in you car and start driving to the observing site, wear a minimum of clothing so as to not start perspiring before you get on location. This includes those heavy winter boots and layers of socks. Many times the first thing to get cold as soon as you get out of your car will be your feet. This happens most often because they are damp from increased perspiration during your trip to the observing site. Take along a change of socks to put on just before you start observing or when your feel start to get cold. Remember dry feet are happy feel!

Some of the best observing can be found during the winter months, so take the time to plan how you are going to dress for your observing sessions. Has one of your long awaited observing sessions ever been cut short because you were too cold and uncomfortable to continue? This can be prevented with some planning and common sense.

Clear skies,

Chase
1/24/2007