Saturday, March 1, 2014

Honoka'a after Dark

The hotel duty manager warned me: Honoka'a shuts down by 8:00 p.m.

That's why I'm here.

It's time to go out on the town. At night, this old sugar cane town takes on an unfamiliar hue, reminiscent of sepia-toned photographs from a different time.  I wonder what is going on.

The sodium street lights seem different from the high-pressure sodium lights of the mainland. But why?

There was some layer to be peeled back, so I Googled and learned these are low-pressure sodium lights. And there is a really good reason for this unusual lighting.

Mauna Kea, a 13,803 foot volcano, rises up behind Honoka'a. Near the summit are some of the world's most powerful telescopes, taking advantage of the clear sky and the low light pollution.
"Most of the lighting under the county jurisdiction uses low-pressure sodium (LPS) lamps. This is the least damaging light source for astronomy because the light is nearly monochromatic, and therefore can be filtered out in some cases." [Reference]

Low-pressure sodium lighting is Honoka'a's contribution to our understanding of the cosmos. It's also more historically sensitive: low-pressure lighting came first, and was gradually replaced by the high-pressure variety in the 1960's.

LED lighting is changing cityscapes all over the world. Sodium lighting is becoming as retro as the rotary phone or vinyl record.

It is good to know Honoka'a will not be installing white LED lighting any time soon. I like walking in an old photograph.

[I'm staying in the Hotel Honoka'a Club, in Honoka'a, the oldest hotel on Hawaii Big Island. It was built by a Japanese American family in 1928, and as I mentioned in a previous post, it retains much of its original character. In the same post I mention another Japanese American, Tom Araki, who worked on the military saddle road during WW2. Back in WW2 I bet he never imagined astronomers from all over the world would be driving up his road.]

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