Alternatives to Mauna Kea

[TomK]

Just say "light pollution". No ambiguity there.

[beejee]

Agreed

1.2) Isolation - middle of the Pacific, low light pollution

[beejee]

@tomk Is there a standard measure of "light pollution"? Is there a device, similar to a light meter for an SLR camera that one can measure "light pollution"?

[TomK]

I'm not aware of one, but will check.

[beejee]

There must be studies as part of the TMT that talk about this, I'll search too.

[TomK]

Here's a start:

http://www.flagstaffdarkskies.org/measur...pollution/

I'm not as up to date on this stuff as I should be. We're an infrared observatory so light pollution isn't too much of an issue, but will play a small part in my more thorough answer.

[beejee]

Understood. In your opinion, do you think "light pollution" is a highly determinant factor for the TMT site selection on Mauna Kea?

[Carey]

The most "standard' scale is the 'Bortle Scale', a 9 level scale the was developed at the turn of the century with 1 being optically dark (native) skies & 9 being inner-city industrial lighted skies

There are now smart phones apps to assist the amateur astronomer, & Dark Sky had this on one:
http://www.darksky.org/component/content...-meter-app

Oh, and some of the questions on why not (from going to a many UHH astronomy talks, Astro talks & Imiloa sky talks...great resources for those really wanting to learn!):
-Haleakala is not has high as Mauna Kea, is close to the inversion altitudes, and as noted, currently also has protesters
-use space (many drawbacks including cost, lack of ability to do routine maintenance, limited mirror size

There are many areas that are used for observation in the northern hemisphere & in the southern hemisphere, but the reasons given by the OP are some of the more compelling to utilize Mauna Kea...

[TomK]

Thanks for the link, Carey. I'm a little skeptical about the info there because I'm not sure you can apply it to Mauna Kea. Sky brightness can also be caused by OH- emission high up in the atmosphere. It's not generally a problem for lower altitude sites as they have enough to contend with, but definitely something an experienced night time observer on MK can see (as can certain instruments). Clear sky, no moon but few stars. You can bet that's OH emission and not a lot we can do about it.

[TomK]

"Understood. In your opinion, do you think "light pollution" is a highly determinant factor for the TMT site selection on Mauna Kea?"

No. It's a factor, but not the most important.