Once in a Red Supermoon: Watch Sunday’s rare lunar eclipse at the George Observatory

Our moon goes by many different names depending on the season and its position relative to the Earth. The evening of Sunday, Sept. 27, it will become three identities at once, an exceptionally rare occurrence. For the first time in 33 years, Earth will witness a total eclipse of the moon at its perigee near the autumnal equinox: a blood moon, a supermoon and a harvest moon combined. You can watch the eclipse of historic proportions anywhere on the planet where the moon is visible, but at the George Observatory, you can learn about eclipses while you catch it in action.

Houstonians will be able to see the whole event, which begins right as twilight ends. Lunar eclipses occur when the full moon moves into the Earth’s shadow. The first part of the Earth’s shadow the moon will encounter is called the penumbra. For our area, sharp-eyed observers will notice only a slight dimming of the moon between 7:10 p.m. and 8:07 p.m. Central Daylight Time (CDT). The moon moves into the darkest part of the Earth’s shadow, the umbra, at 8:07 p.m., and will be totally eclipsed by 9:10 p.m. Totality will last until 10:24 p.m. The moon will then exit the umbra and leave it completely by 11:27 p.m., when the eclipse ends.

eclipse1

This diagram displays the movement of the moon through Earth’s shadow during the total eclipse. Times are shown in Eastern Daylight Time (EDT). For times in CDT, our time zone, subtract an hour.

The moon’s brightness during a total eclipse depends on the amount of dust particles in the atmosphere. A large amount of dust from a volcanic eruption, for example, can make the totally eclipsed moon almost invisible. With little dust in our atmosphere, the moon glows reddish-orange during totality. This is because only the sun’s red light comes through the Earth’s atmosphere and falls on the moon even while it is in the Earth’s shadow. As the diagram shows, the moon passes through the southern part of the shadow, for 74 minutes of totality. As a result, the northern limb, closer to the center of Earth’s shadow, will appear darker.

eclipse2

Sunlight refracted through Earth’s atmosphere gives the moon its red color during a total lunar eclipse, also called a blood moon by many. This is the same red light you see at sunrise and sunset, but from the moon’s perspective. If you were standing on the moon during the eclipse, you would see a dark Earth ringed in a glowing halo of red.

You may have heard that this is a “supermoon eclipse.” That’s because this full moon happens less than one hour after the moon makes its closest approach to the Earth, called perigee. What’s more, this is the closest perigee of the year, 145 km closer than on Feb. 19.  At perigee, the moon is the biggest it can get in our sky, though the difference is only slight. Your pinky held at arm’s length still covers it up!

A supermoon eclipse is a rare phenomenon. The last one occurred in 1982, and there have been only five since 1900. After Sunday, the next one will occur in 2033. Compare this to a blue moon, or two full moons occurring in a month. The last blue moon occurred this year on July 31, and prior to that, on Sept. 30, 2012. Perhaps we should revise the phrase “once in a blue moon” to “once in a red supermoon.”

We can also call this a harvest moon since it’s the full moon closest to the fall equinox. Because the moon rises close to sunset for several days before and after the night of the full moon, its light allows harvesters to keep working instead of stopping at sundown. The fall equinox occurred Wednesday, Sept. 23, so this full moon is indeed the harvest moon, which makes this Sunday’s event a “harvest moon eclipse.”

2

Our own George Observatory will be open Sunday night from 6 p.m. to midnight specifically for observing the eclipse. Here at the Houston Museum of Natural Science, our Starry Night Express shows in the planetarium will feature the eclipse. We’ll also give a preview of the event before every planetarium show that weekend. If you can’t join us here or at the George, just remember that whoever can see the moon can see the eclipse. You can therefore watch the eclipse from your front or back yard, or even out the window if it faces the right angle! Only overcast skies can stop you from seeing the eclipse. Let’s hope our current trend of clear skies holds through Sunday.

This is the last of four lunar eclipses last year and this year, all total, and all visible from North America. That series ends here; in Houston, we’ll see our next total lunar eclipse at dawn Jan. 31, 2018.

Seeing Stars with James Wooten: Lunar Eclipse on April 4

april stars

Mars remains in the west at dusk this month as it moves through Aries. Mars continues to fade a little each night as Earth continues to leave it farther behind. Later on this month, Mars begins to be lost in the glare of the Sun.

Mercury enters the evening sky as Mars leaves it. By April 30, Mars will be gone but Mercury will be low in the west northwest, near the Pleiades star cluster.

Venus is in the west at dusk. Look over the point of sunset for the brightest thing there.

Jupiter is now high in the sky, almost overhead, as soon as night falls. Jupiter outshines all stars we ever see at night, so it will be obvious when you look up at dusk.

Saturn is in the southwest at dawn.

Brilliant winter stars shift towards the west during April. Dazzling Orion is high in the southwest at dusk. His three-starred belt is halfway between reddish Betelgeuse and bluish Rigel. Orion’s belt points right to Aldebaran in Taurus the Bull. Above Orion are the twin stars Castor and Pollux, marking the heads of Gemini, the Twins. Jupiter is among the Twins this month. You can find Sirius, the brightest star we ever see at night, by drawing a line from Orion’s belt towards south (left as you face west). Forming a triangle with Betelgeuse and Sirius is Procyon, the Little Dog Star.

Joining the winter stars are stars of spring in the south and east. Look for Leo, the Lion almost overhead at dusk. In the east, extend the Big Dipper’s handle to ‘Arc to Arcturus’ and then ‘speed on to Spica’.

Moon Phases in April 2015:

Full April 5, 7:05 am

Last Quarter April 11, 10:44 pm

New April 18, 1:56 pm

1st Quarter April 25, 5:55 pm

The Full Moon of April 4 passes through the Earth’s shadow, causing a total lunar eclipse. Unfortunately, the Moon clips the edge of the Earth’s shadow, allowing for only 5 minutes of totality. What’s more, for us the eclipse occurs near moonset and sunrise (which are almost simultaneous when there is a lunar eclipse). That puts the Moon low to the horizon during the eclipse; only those with clear views all the way to the western horizon can get a good look. It also means that totality falls during morning twilight.

Eclipse times:

Partial eclipse begins: 5:15 am
Totality 6:57-7:02 am
Moonset (still partially eclipsed) 7:13 am

On most clear Saturday nights at the George Observatory, you can hear me do live star tours on the observation deck with a green laser pointer. If you’re there, listen for my announcement.

There’s a Partial Solar Eclipse Happening October 23: Here’s what you need to know to see it!

 

There’s a partial solar eclipse happening Thursday, October 23 and you can see it all from Houston*!

 The New Moon of Thursday, October 23, 2014, aligns with the Sun and the Earth well enough to cast its shadow towards Earth. However, no one will see a total eclipse for two reasons. First of all, the Moon was at apogee (greatest distance from Earth) on October 18, and is therefore smaller than usual in our sky. As a result, it is not quite big enough to cover the Sun, and the only eclipse possible would be an annular eclipse. Also, the Moon shadow is aligned to a point in space just over the Earth’s upper limb, so nobody will even get to see an annular eclipse. The near miss, however, allows the penumbra, where the Moon partially blocks the Sun, to land on the Earth. With North America near the upper limb of the Earth at the time, Houston will be within the penumbra. Therefore we will see a partial solar eclipse, in which the Moon will cover almost a quarter of the Sun’s disk at most.

partialeclipse

At 4:59pm CDT, look for the Moon to take a ‘bite’ out of the Sun’s disk. The Moon covers the northern limb of the Sun, which is the right side of the Sun as it sets in the west. Maximum eclipse, with the Moon covering almost 1/4 of the Sun’s disk, is at 5:58.  At 6:43, the Sun sets while still in partial eclipse. After this, the next partial solar eclipse visible from Houston occurs August 21, 2017. 

ECLIPSE TIMES

Eclipse begins: 4:59 PM, CDT
Mid-eclipse: 5:58 PM
Sunset: 6:43 PM

The Museum’s own George Observatory in Brazos Bend State Park will be open to the public from 1:00 -6:00 p.m. on October 23 for observing the Sun and, starting at 5:00, the eclipse.  

*CAUTION: Never look directly at the Sun with the naked eye or through an unfiltered telescope. Permanent eye-damage will result. 

Blood Moon Strikes Back! Total Lunar Eclipse Wednesday, October 8!

A total eclipse of the Moon will occur early Wednesday morning, October 8. Houstonians will be able to see virtually the whole event, which happens right before dawn.

Lunar eclipses occur when the full Moon moves into the Earth’s shadow. The first part of the Earth’s shadow that the Moon will encounter is the penumbra. The penumbral shadow’s faintness means that sharp-eyed observers will notice only a slight dimming of the Moon between 3:14 AM and 4:15 AM. The Moon moves into the darkest part of the earth’s shadow, the umbra, at 4:15 AM, and will be totally eclipsed by 5:24 AM. Totality lasts until 6:25, at which time the Moon has crossed the shadow and begun emerging from the other side. The Moon is still emerging from the shadow (and thus still partially eclipsed) as it sets at 7:26.  Note that this eclipse happens close to dawn, which is when a Full Moon is about to set. Therefore, you’ll need an observing site clear of obstacles to the west so you can watch the setting Moon in eclipse.  (That’s why we’re not observing from George Observatory, as we have in the past. Our tree line would interfere with the view).

Eclipse Diagram - James Wooten

The Moon’s brightness during a total eclipse depends on the amount of dust particles in the atmosphere. A large amount of dust from a volcanic eruption, for example, can make the totally eclipsed Moon almost invisible. With little dust in our atmosphere, the Moon glows reddish-orange during totality. This is because only the Sun’s red light comes through the Earth’s atmosphere and falls on the Moon even while it is in the Earth’s shadow. As the diagram shows, the Moon will pass through the northern part of the shadow, for about an hour of totality. As a result, the southern limb, closer to the center of Earth’s shadow, will appear darker.  And since we’ll be watching the Moon set in the west, the northern limb will be to the right and the southern limb to the left.

This is the second of four consecutive total lunar eclipses in 2014 and 2015, all of which are visible in the USA.  We’ll see our next total lunar eclipse in Houston just before dawn on April 4, 2015.