April 2000

Brrrrrrr!

In my studies of astronomy and physics, I have learned many laws of nature, and one stands out as especially crucial and vexing with respect to my work with the Nightly Observing Program:

"It is always cold at Kitt Peak."

In the winter months, the temperature can easily be in the twenties, and we emphatically warn guests to bring up their entire wardrobes with them in order to stay warm (wear all your clothes. Twelve pairs of socks? Go ahead. Wear your furniture. Wear your pets).

Usually they do, and although they shiver a lot, most of them survive. There are always a handful of guests, however, who come up unprepared, and end up huddling in the Visitor Center while the group is outside (a picture of someone in appropriate attire is at right).

The summer can be worse. While it can be forty degrees warmer than in the winter months, the guests suffer a least as much. How can that be? How can so many people turn blue in sixty-five degree weather?

Two reasons. First, place yourself in the shoes of someone coming up for an early July Nightly Observing Program. You vaguely remember making your reservation weeks ago, when the person on the phone said it would be cold. To get to Kitt Peak on time, you leave Tucson at 5 pm, where the temperature is balmy 140 degrees, cooling from a daytime high of about 190. As you wipe the sweat from your brow and receive second degree burns from your car seat, your mind is completely blocked from remembering to throw a jacket in the trunk. You just can't make yourself do it. And by the time you arrive on the mountain, it begins to dawn on you that your shorts and T-shirt are entirely inappropriate.

The second reason is a combination of "wind chill" and "psyche chill." You are probably familiar with the first term, but let me define the second (since I made it up, after all). "Psyche chill" is an environmental factor that affects how you perceive the cold, independent of wind. People usually experience cold weather in very brief energetic spurts: running across the parking lot from your car to the office, for example.

At Kitt Peak, you are seeing constellations, searching with binoculars, or peering through our telescope. You aren't running, or even walking. And you aren't in much of a hurry at all. Physically, you are spending most of your time, well...

Standing. Or sitting.

In the dark.

These unusual factors create "psyche chill," which makes it seem much, much colder than it actually is. I regularly have people from Minnesota tell me they've never been so cold in their lives. I've seen Canadians cry.

"Ah," I say, "you've never experienced psyche chill before."

So if you're going to join us for the Nightly Observing Program, be sure to bring that jacket. And hat. And gloves. Otherwise, despite a chance to see Saturn and Jupiter in the telescope, all you'll be thinking of is Pluto.

(At left are some NOP guests heading for the telescope.)

Steve White
Nightly Observing Program
Kitt Peak Visitor Center

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Telescope Operators/Guides for Nightly Program:
Adam Block (ablock@noao.edu) Lead Observer
Steve White (swhite@noao.edu)
Flynn Haase (fhaase@noao.edu)
Richard Barchfield (richardb@noao.edu)

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Updated: 01/10/2000