Protection of Mauna Kea and Haleakala Observatories from

Light Pollution

Richard J. Wainscoat

University of Hawaii, Institute for Astronomy

Hawaii’s Population and Geography

• Total population approximately 1.2 million

• 2000 census raw data just released– Honolulu - 800,729– Kauai - 53,546– Maui - 113,933 (location of Haleakala)– Hawaii - 132,636 (location of Mauna Kea)

• 10% statistical correction (undercounting) needs to be applied

Mauna Kea

• Mauna Kea’s huge size affords protection– Very few people live closer than 28km from the

summit

• The largest source of light pollution is Hilo, 40km southeast of the summit. Hilo contributes about 1/3 of the total ight pollution at the summit

Mauna Kea

• There is usually a strong inversion layer, and clouds over the windward side where Hilo is located. These clouds suppress light from Hilo at least 50% of the nights. The annual rainfall in Hilo is 3 to 4 meters.

• The next biggest source of light is Waimea (to the northwest)

• The Kona side (leeward) is usually clear

Mauna Kea

• The Big Island economy is not thriving– Sugar plantations have closed on the Hilo side– Tourism is somewhat depressed, especially

since September 11 (foreign visitors down, domestic visitors up)

– Development is mainly occurring in the north Kona region

Hawaii county lighting ordinance

• Last revised in 1988

• Strengths and features:– Low pressure sodium lighting– Strict limitation on all non-LPS lighting– Bans use of mercury lamps

• Billboards and other large signs are not permitted in Hawaii (state law)

Hawaii county lighting ordinance

• Weaknesses:– Enforcement– Only requires partial shielding of LPS lights -

few street lights are fully shielded– Grandfathering of existing light fixtures

approved by the county before 1988– Does not ban sale of mercury lamps

• Costco in Kona is selling cheap mercury lamps for less than $20, refuses to stop - legislation needed

Hawaii county lighting ordinance

• Revisions under discussion:– Motivated by interpretation problems in

existing ordinance• Problems with a golf driving range and baseball

facility in Kona

– County personnel have been studying Tucson ordinance, and noted 25 and 35 mile radii

• 25 mile circle bisects Hilo

• 35 mile circle excludes parts of Kona

Hawaii county lighting ordinance

• Revisions under discussion:– We have successfully argued that because

Mauna Kea’s telescopes are larger than the Arizona telescopes, that the ordinance must continue to be island-wide

– Interpretation question regarding definition of outdoor lighting

– Street lights are the largest source of artificial light on the island of Hawaii

Hawaii county lighting ordinance

• Revisions under discussion:– Observatories are seeking full shielding on all

future street lights and parking lot lights, and all replacement or repair of these lights

– Observatories are seeking a ban on sale of mercury lamps

– Revisions are expected to be discussed at county council meetings in late summer 2002

Hawaii county council ordinance

• Good public education is essential– Hawaii county is very supportive of astronomy,

but does not want to be the bad guys - staff do not want to take flak for lighting restrictions

– Astronomers must explain to the public why good lighting is essential for astronomy on Mauna Kea

• Need public lectures, editorials, broad support from other groups interested in preserving the dark sky

Light pollution seen from MKO

• The sky above Mauna Kea is still very dark, and the lighting ordinance has been generally effective– It is difficult to measure how much the artificial

light adds to the natural sky brightness, but it is unlikely that it exceeds 5% in any direction

• There is a general consensus among astronomers that lights are increasing, and we need to be more protective

Light pollution seen from MKO

• Typical low-resolution spectrum of the Mauna Kea night sky

Light pollution seen from MKO

• Osterbrock et al. (PASP, 2000, 112, 733) coadded 100 hours of sky spectra from HIRES on the Keck-1 telescope

• Mercury lines are seen in these spectra - the origin is still under investigation– Mercury lamps?– Maui or Oahu (Honolulu)?– Most likely from metal halide lamps

Light pollution seen from MKO

• Maui and Honolulu make small contributions, but sources on the Island of Hawaii dominate

• Worries about non-compliant light sources prompted CFHT staff to start investigations

• Color photographs taken using film and a transmission grating in front of a wide-angle lens

Light pollution seen from MKO• Dispersion in vertical direction

Light pollution seen from MKO

• CFHT telescope operator John McDonald constructed a photo-mosaic from CFHT– Shows light (0th order) and spectra (1st order)– Made from photos on many nights– Uses photos taken only when clear

• Makes light pollution look worse than normal nights

Haleakala

• Although inferior to Mauna Kea, Haleakala is a very good observing site, has good seeing, and is among the best northern hemisphere observing sites

• UH involvement in the past was mostly related to solar astronomy (daytime observations)

Haleakala

• Renewed interest in nighttime astronomy– AEOS telescope (US Air Force - 3.6m)– Magnum telescope (Japan - 2m)– Faulkes telescope (UK - educational - 2m)

Light pollution on Maui

• No lighting ordinance in place• Maui has a similar population to the Island

of Hawaii, but is a smaller island• Haleakala is smaller, and not as high as

Mauna Kea• People live on the slopes of Haleakala• Clouds suppress some lights, but there are

less clouds than in Hilo

Light pollution on Maui

• Light pollution on Maui is approximately 4 times worse than on Mauna Kea based solely on locations of the people and altitude

• Because of the lack of a lighting ordinance, the real situation may be 8 or more times worse

• Artificial light sources may add up to 40% to natural sky brightness at 45o altitude

Proposed Maui lighting ordinance

• A county-wide lighting ordinance is currently being discussed by a subcommittee of the Maui county council

• Main features:– Full shielding of most lights– All street lights, parking lot lights, etc. must be low

pressure sodium and fully shielded– Conformance within 5 years– Bans sale and use of mercury lights

Proposed Maui lighting ordinance

– Existing fully shielded HPS lights may remain– LPS not required for

• Outdoor sales areas during hours of operation

• Assembly/repair areas

• Sports/recreational facilities

• Advertising

• Architectural accent lighting

– Limits service stations and similar places where bright lighting is used as a form of advertising

Proposed Maui lighting ordinance

– Restricts lighting of beaches• Beaches are the nesting habitat of endangered turtles

• LPS has least effect on turtles

• Turtles do not like HPS and metal halide lamps, and will not nest if these lights are visible from the beach

• Turtles seek dark parts of the beaches to lay their eggs

Proposed Maui lighting ordinance

• Opposition is coming from resorts– Color rendition– Liability concerns– Resorts want to light trees and buildings with

upwards shining metal halide lamps

• The fundamental reason for the opposition is money - the resorts do not want to spend money to replace light fixtures

Proposed Maui lighting ordinance

• Maui County may not be willing to spend money on new luminaires (approximately 4,000 street lights)

• Elections are approaching

Proposed Maui lighting ordinance

• Light pollution on Maui is presently so bad that an ordinance that aggressively tackles the problem is necessary– Shielding might achieve a factor 2

improvement– Switching to LPS will help a lot– Special care must be taken in the communities

of Makawao and Pukalani that are close to Haleakala

Proposed Maui lighting ordinance

• Grandfathering existing bad fixtures won’t work - these fixtures must be replaced to address the problem on Maui

• More public education will help

Honolulu

• Light pollution from Honolulu is not presently a major threat to Mauna Kea - it is too far away

• Light pollution from Honolulu is of more concern to Haleakala– There is direct line of site from Haleakala to

Honolulu– Honolulu adds about 2% to the natural light

above Haleakala

Honolulu

• Honolulu’s street lighting is dominantly high-pressure sodium, housed in poorly shielded enclosures

• Honolulu has bad light pollution - it is not possible to see the Milky Way

• Honolulu has a lighting ordinance requiring the use of low pressure sodium lamps (chosen for their energy efficiency)

Honolulu

• The city seems to be largely ignoring this requirement

• One city council member is a strong supporter of good lighting (earlier in his career, he helped draft the original Hawaii county ordinance)

• I plan to work with the council member to ensure that good lighting will be used in future

IDA Hawaii chapter

• Assembling a core group of concerned individuals and organizations on Oahu, Maui and Hawaii

• Most observatories are already IDA members

• We are seeking help from amateur astronomy groups, environmental groups

• Hope to establish Hawaii chapter later in 2002

Multiple jurisdictions

• In the State of Hawaii, highways are state roads, and other roads are county roads

• On the Island of Hawaii, the state highways are maintained by the county of Hawaii, and jurisdictional conflicts are not presently a concern

• However, on Oahu, the state maintains the highways and the county maintains the other roads

Multiple jurisdictions

• We need a state law to improve lighting on state highways to ensure that any new lights are full cut-off

• The state owns all beaches - a change to state law would help reduce the possibility of litigation resulting from stopping lighting the beach

Conclusions

• The night sky above Mauna Kea is still very dark. Contamination by artificial light sources is still very low. However, the population of the Island of Hawaii continues to grow slowly, and continued efforts by astronomers and others are required to maintain the dark sky.

Conclusions

• Increasing interest in nighttime astronomy on Haleakala has prompted efforts to create a lighting ordinance for Maui county. This ordinance is presently being discussed by a sub-committee of the council. Vigorous efforts will be required to pass a strong ordinance. Financial matters are at the core of the opposition.

Conclusions

• There is hope for improvement in the light pollution in Honolulu in the long term.

• Very strong public education and outreach are required for these efforts to succeed.