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2017 Sky Calendar

Seasons and the Sun

Earth Perihelion: Wednesday, January 4, 12:59am 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: Monday, March 20, 12:29am 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: Thursday, May 18, 12:17pm 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: Tuesday, June 20, 6:25pm 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: Monday, July 3, 2:59am 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: Monday, July, 24, 12:27pm 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

 

Partial Solar Eclipse: Monday, August 2, 6:35am HST

On this day, the Moon and the Sun will be perfectly aligned. The moon will block the sun causing a total solar eclipse viewable across the continental United States While Hilo won’t be able to witness the full eclipse; we will see the moon partially block the light of the sun. The sun will rise at 6:02am with the eclipse in progress, Hilo will see maximum eclipse at 6:35am and the eclipse will end for Hilo at 7:22am. 

 

Autumnal/Fall Equinox: Friday, September 22, 10:02am 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: Thursday, December 21, 6:29am 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 – 2017 

 

New Moon

First Quarter

Full Moon

Last Quarter

Jan. 27, 2:07pm HST

Jan. 5, 9:47am HST

Jan. 12, 1:34am HST

Jan. 19,12:07pm HST

Feb. 26, 4:58am HST

Feb. 3, 6:19pm HST

Feb. 10, 2:33pm HST

 Feb. 18, 9:33am HST

Mar. 27, 4:57pm HST

Mar. 5, 1:32am HST 

Mar. 12, 4:54am HST

Mar. 20, 5:58am HST

Apr. 26, 2:16am HST

Apr. 3, 8:39am HST

Apr. 10, 8:08pm HST

Apr. 18, 11:57pm HST 

May 25, 9:44am HST

May 2, 4:47pm HST

May 10, 11:43am HST

May 18, 2:33pm HST

June 23, 4:31pm HST

June 1, 2:42am HST

June 9, 3:10am HST

June 17, 1:33am HST

July 22, 11:46pm HST

June 30, 2:51pm HST

July 8, 6:07pm HST

July 16, 9:26am HST

Aug 21, 8:30am HST

July 30, 5:23am HST

Aug. 7, 8:11am HST

Aug 14, 3:15pm HST

Sept. 19, 7:30pm HST

Aug 28, 11:13pm HST

Sept. 5, 9:03pm HST

Sept. 12, 2:25am HST

Oct. 19, 9:12am HST

Sept. 27, 4:54pm HST

Oct. 5, 8:40am HST

Oct. 12, 2:25pm HST

Nov. 18, 1:42am HST

Oct. 27, 12:22pm HST

Nov. 3, 7:23pm HST

Nov. 10, 10:37am HST

Dec. 17, 8:31pm HST

Nov. 26, 7:03am HST

Dec. 3, 5:47am HST

Dec. 9, 9:51pm HST

 

Dec. 25, 11:20pm 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

Penumbral Lunar Eclipse: Monday, August 7, 2017

Compared to the “Blood Moon” appearances of Total Lunar eclipses, Penumbral Lunar Eclipses are significantly less impressive. During this eclipse the moon will pass through the partial shadow (penumbra) of the Earth; this causes the surface of the moon to darken slightly but not completely. On August 7, the eclipse will start at 5:50am hitting maximum eclipse at 5:53am just before the moon sets at 5:55am

Super Moon on December 3, 2017

When the moon is full at its closest position to Earth, a position called perigee, we refer to it as a super moon. While the super moons will not appear much larger than other full moons (the difference is a few percent) there can be a noticeable difference in the tide as the moon is much closer to Earth. Tides are typically bigger and higher when the moon is at perigee than when it is not.

Major Meteor Showers in 2017

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

Orionids

October 21

20

South Taurids 

November 5

10

North Taurids

November 12

15

Leonids

November 17

15

Geminids 

December 13

120

Ursids

December 21

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

Moon-Venus Conjunction

January 2

Moon-Mars Conjunction

January 8

Mercury-Saturn Conjunction

January 12

Venus Greatest Eastern Elongation

January 18

Mercury Greatest Western Elongation

January 18

Moon- Jupiter Conjunction

January 24

Moon-Saturn Conjunction

January 25

Moon-Mercury Conjuction

January 31

Moon-Mars-Venus Conjunction

February 15

Moon-Jupiter Conjunction

February 20

Moon-Saturn Conjunction

March 1

Moon-Mars Conjunction

March 31

Mercury Greatest Eastern Elongation

April 7

Jupiter at Opposition

April 10

Moon-Jupiter Conjunction

April 16

Moon-Saturn Conjunction

April 23

Moon-Venus Conjunction

May 7

Moon-Jupiter Conjunction

May 13

Moon-Saturn

May 17

Mercury Greatest Western Elongation

May 22

Moon-Venus Conjunction

June 3

Venus Greatest Western Elongation

June 3

Moon-Jupiter Conjunction

June 9

Moon-Saturn Conjunction

June 14

Saturn Opposition

June 20

Moon-Venus Conjunction

June 30

Moon-Jupiter Conjunction

July 6

Moon-Saturn Conjunction

July 20

Moon-Venus Conjunction

July 24

Moon-Mercury Conjunction

July 28

Moon-Jupiter

July 29

Mercury Greatest Eastern Elongation

August 1

Mercury Greatest Eastern Elongation

August 2

Moon-Saturn Conjunction

August 18

Moon-Venus Conjunction

August 25

Moon-Jupiter Conjunction

August 30

Moon-Saturn Conjunction

September 4

Neptune Opposition

September 11

Mercury Greatest Western Elongation

September 16

Mars-Mercury Conjunction

September 17

Moon-Venus Conjunction

September 21

Moon-Jupiter Conjunction

September 26

Moon-Saturn Conjunction

October 5

Venus-Mars Conjunction

October 17

Moon-Mars Conjunction

October 19

Uranus Opposition

October 24

Moon-Saturn Conjunction

November 20

Moon-Saturn Conjunction

December 13

Moon-Mars Conjunction

December 14

Moon-Jupiter Conjunction

 

 

Figure illustrating what is happening during Oppositions and Greatest Eastern/Western Elongation:


 

2016 Sky Calendar 

2015 Sky Calendar