Curtains for civil dawn

I've written in the past about the length of days up here in the PNW, especially for those of us who live north of the 45th Parallel, what I call "past the curve" of the globe.

I've gone on and on, at quite some length, about how late it is before it gets dark. Tonight, for example, sunset does not occur until 9PM, more than half an hour later than in Austin. Ed's not a big fan of the daylight, so how late it gets before it gets dark has been a bit of a focus around these parts, especially during May, June and July.

However, there is another major issue related to the sun, and the length of days: the time of day that it starts getting light out. It's called "civil twilight:" it happens before dawn and after sunset, and I first became acquainted with the notion when Ed and I went to visit Long Beach, WA, and stayed at a B&B with an uncovered skylight in the bathroom.

Civil twilight, according to the Wikipedia peoples:

"This starts in the morning when the geometric center of the Sun is 6° below the horizon (the point of civil dawn), and ends at sunrise. Evening civil twilight begins at sunset and ends when the center of the Sun reaches 6° below the horizon (the point of civil dusk)."

"During this period there is enough light from the Sun that artificial sources of light may not be needed to carry on outdoor activities. This concept is sometimes enshrined in laws, for example, when drivers of automobiles must turn on their headlights, [...] . A fixed period (most commonly 30 minutes after sunset or before sunrise) is typically used in such statutes, rather than how many degrees the Sun is below the horizon."

On the day I laid down the foundation of this post, 5/27, civil twilight began at 4:40 AM in Seattle. In Austin, TX, on the other hand, it didn't begin until 6:04 AM. If you're trying to sleep, I assure you, there is a VERY large difference between shortly after 4:30 in the morning, and after 6 in the morning.

This morning's data regarding civil twilight continues to be painful. Seattle: 4:36 AM; Austin: 6:02 AM.

When one considers these facts, along with the fact that the bulk of our apartment windows face east, one can easily understand my reasons for purchasing blackout curtains for our bedroom.

The upside is, they block out 99% of all sunlight. The first downside is that 1% of all sunlight is a whole hell of a lot more light than one might imagine. The second downside is that they also block out most of the airflow, so it can get stuffy unless the windows are very wide open.

I think my dream condo will have to have light blocking blind/shades/curtains, just so's Ed and I can function in the 3 months surrounding solstice.

6/2/09 P.S. What I didn't mention -- but is of utmost importance up here in cloudy land -- is that during the other 9 months of the year, everyone (including us) does everything they can to maximize the amount of light they can get into their house. But right now, man, is it bright.