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2018 Sky Calendar

Seasons and the Sun 2018

Earth Perihelion: Tuesday, January 2, 4:59am HST

At this time, on this day, the Earth is only about 91.4 million miles (147.1 million kilometers) from the Sun. This position is known as perihelion which is the position in Earth’s elliptical orbit where it is the closest to the sun. There is about a 3 million mile (5 million kilometer) difference between the Earth’s closest position (perihelion) and its furthest position (aphelion).

Vernal/Spring Equinox: Tuesday, March 20, 6:15am HST

This day marks the Vernal or Spring Equinox when the sun will be rising exactly east and setting exactly west. In the Northern Hemisphere it is celebrated as the first day of spring. Despite the name ‘equinox’ this day will not actually have equal parts daytime and nighttime. In Hilo, March 14, will be the day with the closest amount of equal day and night with the day lasting 12 hours and 41 seconds. 

Lahaina Noon: Friday, May 18, 12:16pm HST

This date marks the first of 2 special days called Lahaina Noon. Lahaina Noon is the Hawaiian term for the tropical phenomena that sees the sun pass directly overhead at solar noon- as a result, vertical objects, like lamp posts, will cast no shadow. Here at ‘Imiloa, our skylight will perfectly illuminate the mosaic on our atrium floor. The exact date and time of Lahaina Noon will depend on our latitude in the tropics; this date and time is for Lahaina Noon in Hilo. 

Summer Solstice: Thursday, June 21, 12:07am HST

This day marks the Summer Solstice when the tilt of the Earth positions the Sun directly over the Tropic of Cancer. On this date the sun will rise and set at its northernmost point in the sky. This date is often considered the first day of summer for the Northern Hemisphere and the Northern Hemisphere will experience its longest day with 13 hours 19 minutes and 22 seconds of daylight for Hilo.

Earth Aphelion: Friday, July 6, 5:59am HST

At this time, on this day, the Earth is 94.5 million miles (152 million kilometers) away from the sun. This position is known as aphelion which is the position in Earth’s elliptical orbit where it is the furthest from the sun. There is about a 3 million mile (5 million kilometer) difference between the Earth’s closest position (perihelion) and its furthest position (aphelion).

 

Lahaina Noon: Tuesday, July 24, 12:26pm HST
This time and date marks the second instance of Lahaina Noon, when the sun will appear directly over head at solar noon. This is an event that can only be experienced in the tropics. The exact date and time of Lahaina Noon will depend on your latitude in the tropics; the above date and time are for Hilo

 

Autumnal/Fall Equinox: Saturday, September 22, 3:54pm HST

This day marks the Autumnal or Fall Equinox, the second time this year where the sun will be rising exactly east and setting exactly west. In the Northern Hemisphere this day marks the first day of autumn. Despite the name ‘equinox’ this day will not actually have equal parts daytime and nighttime. In Hilo, September 28th will be second day with the closest amount of equal day and night with the day lasting 12 hours and 6 seconds. 

Winter Solstice: Friday, December 21, 12:22pm HST

This day marks the Winter Solstice when the tilt of the Earth positions the Sun directly over the Tropic of Capricorn. On this date the sun will rise and set at its southernmost point in the sky. This date is often considered the first day of winter for the Northern Hemisphere and the Northern Hemisphere will experience its shortest day with only 10 hours 56 minutes and 33 seconds of daylight for Hilo. 

 

Note 1: HST is the abbreviation for Hawaii Standard Time. HST is 10 hours behind Coordinated Universal Time (UTC). 

Note 2: Hawaii does not observe Daylight Saving Time


Phases of the Moon – 2018 

 

New Moon

First Quarter

Full Moon

Last Quarter

 

Jan. 16, 4:17pm HST

 

Jan. 24, 12:20pm HST

Jan. 1, 4:24pm HST

Jan. 31, 3:27am HST

Jan. 8, 12:25pm HST

Feb. 7, 5:54am HST

Feb. 15, 11:05am HST

Feb. 22, 10:09pm HST

Mar. 1, 2:51pm HST

 Mar. 9, 1:20am HST

Mar. 17, 3:12am HST

Mar. 24, 5:35am HST 

Mar. 31, 2:37am HST

Apr. 7, 9:18pm HST

Apr. 15, 3:57pm HST

Apr. 22, 11:46am HST

Apr. 29, 2:58pm HST

May. 7, 4:09pm HST 

May 15, 1:48am HST

May 21, 5:49pm HST

May 29, 4:20am HST

June 6, 8:32am HST

June 13, 9:43am HST

June 20, 12:51am HST

June 27, 6:53am HST

June 5, 9:51pm HST

July 12, 4:48pm HST

June 19, 9:52am HST

July 27, 10:21am HST

Aug. 4, 8:18am HST

Aug 10, 11:58pm HST

Aug. 17, 9:49pm HST

Aug. 26, 1:56am HST

Sept. 2, 4:37pm HST

Sept. 9, 8:01am HST

Sept. 16, 1:15pm HST

Sept. 24, 4:53pm HST

Oct. 1, 11:45pm HST

Oct. 8, 5:47pm HST

Oct. 16, 8:02am HST

Oct. 24, 6:45am HST

Oct. 31, 6:40am HST

Nov. 7, 6:02am HST

Nov. 15, 5:54am HST

Nov. 22, 7:18pm HST

Nov. 29, 2:19pm HST

Dec. 6, 9:20pm HST

Dec. 15, 1:49am HST

Dec. 22, 7:49am HST

Dec. 28, 11:34pm HST

 

     

 

 

Note: The moon's phase is determined by the position of the moon in relation to the Sun and the Earth. The descriptions of Full, First Quarter, New and Last Quarter refer to specific orientations of the Moon, Sun and Earth. The times on these tables are the exact times the moon will be in the precise orientation; however the moon will not necessarily be visible in the Hilo sky at these times. 

Note 1: HST is the abbreviation for Hawaii Standard Time. HST is 10 hours behind Coordinated Universal Time (UTC). 

 

Note 2: Hawaii does not observe Daylight Saving Time

 


 

Special Lunar Events

Super Moon: Tuesday, January 2, 2018

The moon's orbit around the Earth is not a perfect circle; it is an ellipse. Thus there is a point in the moon's orbit where it is closest to Earth, called perigee; and a point where it is furthest from Earth, called apogee. Every month the moon passes through these points, however, when it is full and at these points it can be referred to as a Supermoon (at perigee), or Micromoon (at apogee). On January 2 the moon is at perigee while it is full and it appears to be slightly larger in the sky.

Super Blue Blood Moon: Wednesday, January 31, 2018

In 2018 there are two full moons in January; one on the first day of the month and one on the last. When this happens the second full moon is often referred to as a blue moon even though the moon's color remains the same. On January 31 the blue moon will also coincide with the moon's perigee, giving January its second supermoon. To top it off, between 3pm and 5pm (HST) the moon will pass through the Earth's shadow in a lunar eclipse, which is often referred to as a "blood moon". On January 31 look forward to viewing a "super blue blood moon."

Blue Moon: Saturday, March 31, 2018

When a calendar month contains 2 full moons, the second full moon is often referred to as a "blue moon." In March of 2018 there will be a full moon the night of March 1 and a "blue moon" the evening of March 31.

Major Meteor Showers in 2018

Name

Peak Date*

Zenith Hourly Rate** 

Quadrantids

January 3

120

Lyrids 

April 22

20

Eta Aquarids 

May 4

60

Delta Aquarids 

July 27

20

Persieds 

August 12

90

South Taurids

November 5

10

North Taurids 

November 12

15

Leonids

November 17

15

Geminids

December 14

120

Ursids

December 22

10

 

 

 

*While meteor showers will peak on specific dates, the meteors of those showers are still visible for the days prior to and following the peak date.

 

**The Zenith Hourly Rate (ZHR) of a meteor shower is the number of meteors an observer could expect to see in an hour at peak activity.

 


Planetary Events

A conjunction is when celestial objects appear to be very close together (within a few degrees) in our sky. A planet will frequently conjunct with celestial objects as well as other planets. Ancient astronomers attached a good deal of significance to these events. Today, while they are not as important to astronomers, they still appear to be very pretty in our sky. 

Opposition is when an outer planet (Mars, Jupiter, Saturn etc.) is on the opposite side of the sun in our sky. At this time the Earth is as physically close to the planet as Earth can get and the planet will rise at the exact same time the Sun sets. Sometimes the planet will appear to be slightly brighter at that time.

 

Greatest Eastern/Western Elongation describes when either Mercury or Venus are at their highest points in either the Eastern (early evening) sky or Western (early morning) sky.

Date

Event

January 1

Mercury Greatest Western Elongation

January 6

Mars-Jupiter Conjunction

January 12

Mercury-Saturn Conjunction

March 15

Mercury Greatest Eastern Elongation

March 18

Venus-Mercury Conjunction

April 2

Mars-Saturn Conjunction

April 24

Venus-Pleiades Conjunction

April 29

Mercury Greatest Western Elongation

May 8

Jupiter Opposition

June 27

Saturn Opposition

July 11

Mercury Greatest Eastern Elongation

July 29

Mars Opposition

August 17

Venus at Greatest Eastern Elongation

August 26

Mercury at Greatest Western Elongation

September 1

Neptune Opposition

October 1

Mercury-Venus Conjunction

October 23

Uranus Opposition

October 28

Mercury-Jupiter Conjunction

November 6

Mercury at Greatest Eastern Elongation

December 15

Mercury Greatest Western Elongation

December 21

Mercury-Jupiter Conjunction