Stargazers in California and Arizona love to tell stories about how tough their compatriots in the northern U.S. are. "The temperature was in the upper thirties," goes a typical story, "and this guy from Massachusetts shows up in only shorts and a T-shirt."

I'll tell you one thing about this story — the guy in a T-shirt wasn't me! I love cold weather, but I hate being cold, so I make sure that I'm always wearing more than enough clothing. It's not rare for me to wear a down jacket on a cool evening in August, and I never go out without a warm winter hat if I'm expecting temperatures lower than 60° F.

I often remind people that a chain is only as strong as its weakest link. The thickest jacket in the world won't keep you warm if your head is bare, or if you're wearing regular street pants or shoes. But I recently realized that since I'm so careful about all those other body parts, my jacket is often the weakest link.

Back in January, I had one night with a good chance of seeing the tail of Comet McNaught protruding into the northern sky after the comet's head had gone south. It was forecast to be one of the coldest nights of the year, with a temperature around 0° F, and much worse, a very strong wind blowing out of the west — where I would ned to be facing. So I scoured my apartment for the gear that I wore back in my days of ice climbing on Mount Washington, New Hamsphire, which is often stated (not quite accurately!) to have the worst weather in the world.

The upshot was that I didn't even feel a hint of chill after an hour and a half in the coldest astro-weather I'd ever experienced. The key garment turned out to be an expedition down parka that I'd nearly forgotten I owned. Not only did it keep my upper body warm, but the fact that I was losing essentially no heat from my torso and head meant that my hands and feet stayed toasty too.

Last Sunday evening I found myself in the country on an unexpectedly clear night. The conditions were relatively mild, with gentle breezes and temperatures in the teens, but I decided to wear the monster down parka anyway. Why not be as comfy as possible?

The good news is that I had a splendid night of observing — which with any luck, I'll be writing about later. The bad news is that I stayed out much too late.

What's wrong with that? Well, the next day I had to get up, pack up my gear, and drive 2½ hours to work. Since I work for an astronomy magazine, I was forgiven for coming in late, but my body still hasn't forgiven me for all the sleep I missed. And truth be told, the last hour I was out observing, my brain had slowed to a crawl; I would have done nearly as much if I'd knocked off at 1 a.m. instead of 2:30 a.m. If I'd worn my usual clothing, I would have stopped earlier because I was cold. But swaddled in my wonderful parka, I blissed out under the stars without realizing how late it was getting.