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.

A Reminder on Safe Solar Viewing

With the transit of Mercury on Monday a reminder on how to view the Sun safely is in order. I have posted on this subject many times in the past and maintain a full post on the various techniques one can use to safely view the Sun.

Scott in the Sun
Scott showing folks the Sun with a white light solar filter

Since Mercury is quite small you will want a bit of magnification to view the event properly. If you do not have a good solar filter for your telescope come to a local event where telescopes are available.

On Hawaiʻi island you can either go to the W. M. Keck Observatory HQ in Waimea or Subaru Observatory HQ in Hilo. Both observatories are hosting transit events at dawn Monday morning 11 Nov, 2019.

These events start at 6am with webcasts of the transit from other observatories further east, with the Sun rising far enough to see the transit from 7-8am.

Transit of Mercury Nov 11, 2019

On November 11th, 2019 Mercury will transit the Sun. While transits of Mercury are not rare, they are not all that common either. The last transit was a few years ago in May of 2016. On average there are fourteen transits of Mercury each century or one every seven years. If you wish to observe one the situation is much better than transits of Venus which occur in pairs over a century apart.

Mercury Transit 9May2016
Mercury transiting the Sun on May 9, 2016. Celestron C8 and Canon 6D at f/10.

This particular transit will favor observers in Europe, South America, and the eastern seaboard of North America where the entire transit will be visible. Unfortunately for observers in the islands only the final hour and a half of the transit will be visible having begun well before local dawn. Sunrise will occur around 06:28 for the island of Hawaiʻi, with the transit ending at 08:04 in the morning when the Sun will be 20° above the horizon.

Continue reading “Transit of Mercury Nov 11, 2019”

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 setting Sun in the evening sky. After today the planet will slide back into the Sun’s glare headed for inferior conjunction on November 11th.

This is a good apparition, with the planet over 24° from the Sun at maximum.

Continue reading “Mercury at Maximum Elongation”

Autumnal Equinox

The fall equinox will occur at 21:50HST today.

Sunrise over Georgia Strait
Sunrise over Georgia Strait

The equinox is defined as the time at which the Sun passes through the plane of the Earth’s equator. Until the next spring equinox occurs in 2020, the Sun will be located in the southern hemisphere with a negative declination coordinate.

Today the length of the day and night will be very near equal, thus the term equinox. the Sun will rise and set nearly exactly due east and due west.

Today is considered the start of fall for most cultures in the northern hemisphere, or the start of spring 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