Seeing Stars with James Wooten: Planets near alignment, Astronomy Day arrives, and the clock ‘falls back’ this October

October Seeing Stars

Saturn is now in the southwestern sky at dusk. It outshines the stars around it, so it’s also easy to see. By Halloween night, however, Saturn sets in twilight; it drops into the Sun’s glare next month. 

Venus, Mars, and Jupiter will come close together in the sky late this month. Right now, the three planets are almost in a vertical line, with Venus, Jupiter on the bottom, and Mars in between. Venus is brighter than Jupiter and both outshine all stars we ever see at night, so they’re easy to find even in twilight. Mars is much, much dimmer than those two. It is now just below (and slightly dimmer than) the star Regulus in Leo.  During this month, watch as Mars gains on Jupiter and Venus gains on them both. Mars overtakes Jupiter Oct. 17, when they are just 0.38 degrees apart. By way of comparison, your pinky held at arm’s length blocks about one degree. Venus then passes one degree from Jupiter Oct. 26. That morning, the three planets form the most compact alignment, fitting within a circle 3.35 degrees across. Venus goes on to overtake Mars the morning of Nov. 3. They are 0.68 degrees apart that morning.

The Big Dipper is left of the North Star, with its handle pointing up. From that handle, you can ‘arc to Arcturus’ in the west at dusk. 

Autumn represents sort of an ‘intermission’ in the sky, with bright summer stars setting at dusk, while bright winter patterns such as Orion have not yet risen. The ‘teapot’ of Sagittarius sets in the southwest early in the evening. The Summer Triangle is high in the west. Meanwhile, the Great Square of Pegasus is in the east, indicating that autumn has begun. The stars rising in the east are much dimmer than those overhead and in the southwest because when you face east at dusk in October, you face out of the Milky Way plane. The center of our galaxy lies between Scorpius and Sagittarius, while the Summer Triangle is also in the galactic plane. Pegasus, on the other hand, is outside the plane of our galaxy and is a good place to look for other galaxies. Nearby constellations Andromeda and Triangulum (a small triangle) contain the spiral galaxies nearest to our own.

Moon Phases

Moon Phases in October 2015:

Last Quarter: Oct. 4, 4:06 p.m.

New: Oct. 12, 7:06 p.m.

1st Quarter: Oct. 20, 3:31 p.m.

Full: Oct. 27, 7:05 p.m.

Our annual Astronomy Day at the George Observatory is Saturday, Oct. 24! On Astronomy Day, we have activities from 3 to 10 p.m., and all of the telescopes, even the ones that normally cost $5 to look through, are free. It’s the biggest astronomy event in southeast Texas! Click here for more information.

Halloween is on Saturday this year, which means that the next day, Nov. 1, is the first Sunday of November. Therefore, Daylight Saving Time ends and we ‘fall back’ to standard time at 2 a.m. that morning. (The time goes from 1:59 a.m. back to 1 a.m., giving us the 1 a.m. hour twice.) So get your #ChillsAtHMNS, don’t forget to set your clocks back, and enjoy your extra hour of sleep Halloween night!

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. 

Clear Skies!

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.”

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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: Total Lunar Eclipse this Month

Stars

Saturn is now in the southwestern sky at dusk. It outshines the stars around it, so it’s also easy to see. 

Mars is a little higher in the morning sky this month. Look for it low in the east at dawn. Mars remains dimmer then average, though, and won’t rival the brighter stars until next spring.  

Venus and Jupiter reappear in the morning sky this month. Venus is already visible in the east at dawn; Jupiter will join it after the middle of the month. Venus outshines everything but the Sun and the Moon, while Jupiter is next brightest after Venus. Both, then, easily outshine all the stars we see at night and are clearly visible even in twilight.

Venus, Mars, and Jupiter will come close together in the sky late next month.

The Big Dipper is left of the North Star, with its handle pointing up. From that handle, you can ‘arc to Arcturus’ in the west at dusk. 

Antares, brightest star of Scorpius, the Scorpion, is in the southwest, with the ‘teapot’ of Sagittarius to its left. Saturn is to the right of the scorpion’s head. The Summer Triangle is overhead. The Great Square of Pegasus is now in the east, indicating the approaching fall.

Phases10-9x-3w

Moon Phases in September 2015:

Last Quarter: Sept. 5, 4:54 a.m.

New: Sept. 13, 1:41 a.m.

First Quarter: Sept. 21, 3:59 p.m.

Full: Sept. 27, 9:50 p.m.

The Full Moon of September 27 enters the Earth shadow, causing a total lunar eclipse. Partial eclipse begins at 8:07 pm CDT, about an hour after sunset and right as twilight fades. The Moon is totally eclipsed by 9:10. Totality lasts 74 minutes, until 10:24. The Moon then comes out of eclipse until the eclipse is over at 11:27. This is the last of a series of four total lunar eclipses in 2014-2015, all visible from Houston. Unlike the previous three, which occurred at midnight or at dawn, this eclipse takes place in evening hours while everyone is still awake. Remember, whoever can see the Moon can watch the eclipse. Let’s hope the weather cooperates and we can all enjoy it. Our George Observatory will be open Sunday evening, September 27, for this event.

If we miss this eclipse, the next one we can see is at dawn Jan. 31, 2018.

At 3:21 a.m. on Wednesday, Sept. 23, the Sun is directly overhead at the equator, shifting southwards. This, then, marks the autumnal equinox, the ‘official’ start of fall. On this date (and on the spring equinox in March) everyone on Earth has the same amount of daylight.  After this date, night is longer than day for us and keeps getting longer until our longest night at the winter solstice. Below the equator, day becomes longer than night after this equinox. It is springtime down there. 

Planetarium Schedule

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.

Clear Skies!

Seeing Stars with James Wooten: Saturn and Perseid meteors bright in August

Star map Aug

Saturn is now in the south-southwestern sky at dusk. It outshines the stars around it, so it’s also easy to see.

Mars emerges into the morning sky this month. Look for it low in the east at dawn.  Mars remains dimmer then average, though, and won’t rival the brighter stars until next spring.

Venus and Jupiter are in line with the Sun and out of sight this month. Venus emerges into the morning sky fairly quickly, though; try looking for it low in the east at dawn the last week of August.

The Big Dipper is left of the North Star, with its handle pointing up. From that handle, you can ‘arc to Arcturus’ and then ‘speed on to Spica’; those stars are in the southwest at dusk.

Antares, brightest star of Scorpius, the Scorpion, is in the south, with the ‘teapot’ of Sagittarius to its left. Saturn is to the right of the scorpion’s head. The Summer Triangle is almost overhead. The Great Square of Pegasus now rises soon after dusk, indicating that despite this 100 degree heat, autumn is on the way.

 

Phases10-9x-3w

Moon Phases in August 2015:

Last Quarter: Aug. 6, 9:03 pm

New: Aug. 14, 9:53 am

First Quarter: Aug. 22, 2:31 pm

Full: Aug. 29, 1:35 pm;

The annual Perseid Meteor Shower peaks every year in mid-August—this year on Aug. 13. Remember that this is a shower, not a storm; you can expect a meteor per minute on average. Also, Earth is actually running into the meteor stream, rather than the meteors running into us. This means that the shower gets better as you get closer to dawn. Our George Observatory will be open late Wednesday night, Aug. 12, until 2 a.m. and Thursday, Aug. 13, for viewing the Perseids. 

For the Planetarium schedule, see www.hmns.org

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. I generally do one such tour on short August evenings.

Clear Skies!