Full Moon

Full Moon
Full Moon taken 27Aug2007

Full Moon will occur today at 11:38HST.

This evening look for the Moon rising in the east just as the Sun sets in the west. Across the Big Island this can often lead to moonbows as the low elevation moonlight interacts with fog and clouds.

A partial lunar eclipse will be visible in Europe, India, and Africa. None of this eclipse will be visible here in the islands.

Continue reading “Full Moon”

Will TMT Be The Biggest Building on the Island?

You see this claim bandied about routinely in newspaper comment sections and Facebook, It has several variations, from biggest, tallest, to largest, to most area. This has been repeated since the beginning of the controversy and continues to the present as a protester staple.

TMT Rendering
An overhead view of the proposed Thirty Meter Telescope, credit TMT Observatory Corporation

This particular myth is easily disproved as there are any number of buildings on the island that are much larger in several respects. All you need is some elementary school math.

Continue reading “Will TMT Be The Biggest Building on the Island?”

The Moon and Saturn

This evening, July 15th, the Moon will pass quite close to Saturn. For viewers in the islands the pair will be closest as it grows dark, slowly separating as the night advances.

Saturn on April 15th, 2016

At sunset the two will be separated by about 40 arcminutes. Keep in mind that is a center to center distance, considering the size of the moon this puts the planet about 25 arcminutes from the limb of the Moon, close enough to appear in the field of a medium power eyepiece in most amateur telescopes.

Viewers in the South Pacific and Australia will be able to view an occultation of Saturn by the Moon this evening.

As the Moon is also quite close to full it will be rising at sunset, thus a good eastern horizon is desirable to see this event early in the evening. Look for a bright, slightly yellowish star-like object just north of the Moon as it rises.

The Calm Before the Storm

You almost certainly know by now, the Thirty Meter Telescope will restart construction this coming Monday. It was announced in a live press conference Monday from the governor’s office. At 7am Monday, July 15th, the Mauna Kea Access Road will be closed to permit the passage of heavy equipment.

Mauna Kea Protest
Protests on Mauna Kea, June 24, 2015. Photo by Dan Birchall, used with permission.

With this both sides are preparing for the coming confrontation. The protesters are rallying the troops, the state and county have had the response plans in place for a while.

Meanwhile the observatories prepare to get jammed in the middle. We have cancelled planned maintenance operations and stationed a minimum crew in the dorms at Hale Pohaku, just a few guys to keep the telescopes on-sky if the road is impassable due to the protests.

There are already a few protesters on the mauna, a few vehicles at Puʻu Huluhulu, a few to be seen along the summit road. It appears that the larger gatherings will occur over the weekend.

It appears both side expect the action to be at the Mauna Kea Access Road and Saddle Road junction rather than at Hale Pohaku like last time. The plan seems to be forcing the protesters further down the mountain. Actually that is a good plan, safer for everyone protesters included with good road access adjacent to Saddle Road, lower in elevation.

Personally? I was scheduled to go up next week, I cancelled that, opting to go up this Friday to get a last few things done. I may possibly take a turn as part of the minimal crew staying on the mauna for a few days depending on the protests and the ability of law enforcement to keep the road open.

Saturn at Opposition

Today the planet Saturn will pass through opposition, directly opposite the Sun in our sky.

Saturn on April 15th, 2016

Saturn orbits the Sun once every 29.45 years. As the ringed planet continues on its way the Earth swings around much faster on our inside track. As a result we lap Saturn once every 378.1 days, passing between the planet and the Sun. During opposition Saturn will be well placed for observation all night long, rising at sunset, transiting at midnight, and setting at sunrise.

During opposition the planet and rings will be slightly brighter than normal, an effect known as the opposition effect. The effect is most notable in the rings where the apparent brightness can increase by 30%. The effect is a combination of two factors, shadow hiding and the retro-reflective properties of the ring particles.

A Second Chance for Lāhainā Noon

Lāhainā Noon is that moment when the Sun is directly overhead. At the moment of Lāhainā Noon shadows disappear.

The first Lāhainā Noon of the year occurs in May as the Sun is moving northwards in the sky. The second chance to see Lāhainā Noon is in July as the Sun moves back to the south.

The table below gives the dates and times for this second Lāhainā Noon across the islands.

Lahiana Noon for July 2019
Naalehu 155°35’W19°03’NJul 2712:29HST89.9
Hilo 155°05’W19°42’NJul 2412:27HST89.9
Kona 155°59’W19°39’NJul 2512:30HST89.9
Waimea 155°40’W20°01’NJul 2312:29HST89.9
Hawi 155°50’W20°14’NJul 2212:30HST89.9
Hana 156°00’W20°46’NJul 1912:30HST89.9
Kihei 156°27’W20°45’NJul 1912:32HST90.0
Kahalui 156°28’W20°53’NJul 1812:32HST89.9
Lahaina 156°40’W20°53’NJul 1812:33HST89.9
Lanai City156°55’W20°50’NJul 1812:34HST89.9
Kaunakakai157°01’W21°05’NJul 1712:34HST89.9
Honolulu 157°49’W21°18’NJul 1612:37HST89.9
Kaneohe 157°48’W21°25’NJul 1512:37HST89.9
Waialua 158°08’W21°34’NJul 1412:38HST89.9
Lihue 159°22’W21°58’NJul 1112:43HST89.9
Data from US Naval Observatory Data Services


Earth’s apehelion will occur at 12:11HST today.

Sunrise over Georgia Strait
Sunrise over Georgia Strait

Apehelion occurs when the Earth reaches its furthest distance from the Sun for the year.

It may seem odd to some the apehelion occurs in the middle of summer. One must recall that the distance from the Sun is not the cause of our seasons, that is the effects of axial tilt.

2019 Apsides and Seasons
Event Universal TimeHawaii Standard Time
Perihelion Jan 0305:20UTJan 0219:20HST
Spring Equinox Mar 2021:58UTMar 2011:58HST
Summer SolsticeJun 2115:54UTJun 2105:54HST
Aphelion Jul 0422:11UTJul 0412:11HST
Fall Equinox Sep 2307:50UTSep 2221:50HST
Winter SolsticeDec 2204:19UTDec 2118:19HST
Data from US Naval Observatory Data Services