Winter Solstice

The winter solstice will occur at 18:19HST today.

Sunrise over Georgia Strait
Sunrise over Georgia Strait

The Sun has reached the most southerly declination it will achieve this year. After today the Sun begins to move north in our skies.

Today will be the shortest day of the year for those of us located in the northern hemisphere.

Today is considered the start of winter for most cultures in the northern hemisphere, or the start of summer for those in the southern hemisphere.

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

Mercury at Maximum Elongation

Mercury, Venus and Jupiter
An evening conjunction of Mercury, Venus and Jupiter on 30 May, 2013

Today Mercury is passing through maximum elongation, the furthest it will rise above the rising Sun in the dawn sky. After today the planet will slide back into the Sun’s glare headed for superior conjunction on January 10th.

This is a modest apparition, with the planet only 20° from the Sun.

Continue reading “Mercury at Maximum Elongation”

New Moon

Young Moon
A very young moon over Waikoloa

New Moon will occur today at 05:06HST.

Over the next few days a slim crescent Moon will slide through a number of bright planets low in the sunset including Jupiter, Venus, and Saturn.

This coming weekend, Nov. 30th, offers an excellent night for observing with a slim 4 day old Moon in the sunset. Get out and enjoy the dark!

Continue reading “New Moon”

Venus and Jupiter

Observant sky watchers will have noticed that the two brightest planets in our skies have been drawing close together. Jupiter and Venus are currently about 2° apart. Sunday evening will see them at their closest for viewers in the islands at just under 1.5° apart. Monday will see the pair very slightly further apart at just over 1.5° separation.

Venus and Jupiter over the Keck 1 dome

After Monday the two will gradually separate further with Jupiter disappearing into the sunset in mid-December while Venus continues to climb further from the Sun until maximum elongation on March 24, 2020.

On Wednesday the 27th a thin crescent Moon will join these bright planets, just 5° below Jupiter. On Thursday the 28th the Moon will be 4° above Venus. The three should make for quite a spectacular sight in the glow of sunset.

A degree and a half separation will allow both to fit in the field of view of very low power telescopes and binoculars, a bit much to fit both in the field of view of most telescopes.

Mercury Transit 2019

It was a clear predawn sky that greeted Waimea this morning, perfect to watch the transit of Mercury across the Sun.

The transit of Mercury on the morning of Nov 11, 2019
The transit of Mercury on the morning of Nov 11, 2019

An alarm set for o-dark-thirty and a drive to Waimea with the first glow of dawn behind the mauna. I did not have to pack a ‘scope as I would be using an observatory outreach telescope, just make sure I have camera gear ready.

Realistically I was expecting only a few folks in addition to the club members I knew were coming. A light crowd maybe? Thus I was rather surprised to find the parking lot filling quickly and our big conference room buzzing at 6am.

It was quite the crowd considering the Sun had not yet appeared over the shoulder of the mauna!

Continue reading “Mercury Transit 2019”

Mercury at Inferior Conjunction

Today Mercury is passing through inferior conjunction, passing between the Sun and the Earth. This fast moving planet will reappear above the dawn in about a week, rising towards maximum elongation on November 28th.

On this particular conjunction the planet will transit the Sun.

This will be a modest apparition, with the planet reaching only 20° away from the Sun.

Mercury Events for 2019
ApparitionDate ElongationMagnitude
Evening Feb 2718.1°E -0.2
Morning Apr 1127.7°W +0.6
Evening Jun 2325.2°E +0.7
Morning Aug 919.0°W +0.3
Evening Oct 2024.6°E +0.1
Morning Nov 2820.1°W -0.3
Data from the Mercury Chaser’s Calculator by John Walker

Transit of Mercury Reminder

Mercury Transit 9May2016
Mercury transiting the Sun on May 9, 2016

Tomorrow morning, November 11th, there is a transit of Mercury. For observers here in the islands the event will be in progress when the sun rises, only the last hour and a half of the even visible.

You can read a full post with all of the event details here.

This is the last transit of Mercury until 2032, you might want to get out to see this one.

Leonid Meteor Shower

The Leonids are one of the better known annual meteor showers. Some years see high Leonid activity, with amazing numbers of meteors. This shower has occasionally created true meteor storms. Unfortunately 2019 is not predicted to be one of those years, with very modest numbers expected.

Leonids in Orion
A pair of Leonid meteors streak through Orion

Due to the gravitational influence of Jupiter, the Leonids are not expected to produce any exceptional showers for some decades. We are unlikely to see any repeats of the early 21st century storms anytime soon.

The shower will peak on November 17, with an expected ZHR of around 15 meteors per hour. The Leonids exhibit a broad peak allowing viewing for days before and after maximum. Moonlight is a bit of an issue with a waning gibbous Moon 5 days after full on the 17th.