Eta Aquarid Meteor Shower 2011

Meteors are wonderful to see, arriving unannounced and fleeting in an instant across the sky, obligating the hopeful viewer to pay attention or miss this spectacle of the heavens. On any given night if you simply are out viewing the skies, you will probably see one or two, but throughout the year there are special times when the Earth's orbit takes us through a region of space dust, creating meteor showers, in which the intensity and regularity of meteors increases dramatically.

The Eta Aquarid meteor shower peaks Thursday night, the night of May 5th into the morning of May 6th. This is not the biggest meteor shower of the year, but it certainly is interesting because it is caused by small bits of debris from the trail of Halley's Comet, the famous comet that orbits the Sun and is visible from Earth every 76 years. Comets leave small trails of debris in their wake, and comets that have orbits that intersect the orbit of Earth around the Sun create our annual meteor showers. So if you see an Eta Aquarid meteor tonight, you'll know it was once part of Halley's Comet, having been stripped away by the heating of the Sun on some past fly-by of Earth.

To see this shower, as is the case for all meteor showers, you need a dark location (even a backyard shielded from streetlights in the city will do), warm blankets, a recliner chair or a patch of grass to lie on, a big view of the sky, and patience. The name of this shower is based on Aquarius (the constellation) where the meteors appear to originate from, but they are visible all over the sky. Best viewing for this shower is early morning. The dawn sky will start to brighten around 5:00 am, so you will need to start early Friday morning if you want to see these. Have fun!

The Last Vestiges of the Winter Sky

The young Moon graces the last vestiges of the winter sky this week, creating a beautiful pattern in the west for several evenings in a row. The big, bold constellations of winter including Orion, Taurus and Canis Major, and the very distinctive asterism the Winter Triangle are sinking lower each evening into the glow of the sunset sky, and on May 4th, 5th and 6th the Moon enters the picture to create a spectacular evening picture.

I have been doing Star Parties and outdoor presentations on astronomy the last few weeks, and the change from week to week has been dramatic. There is a natural change to the sky each evening, as the constellations and bright stars along the celestial equator and zodiac (ecliptic) move approximately 1 degree westward toward the sunset. At the same time, the length of each day is growing, meaning that these great winter constellations are disappearing rapidly into the glare of sunset. But there is nothing to worry about -- they will make their way around the sky to rejoin the view in the early morning, and continue the great ritual of the sky changing slowly from one season to the next.

Viewing Gemini and a Deep Space Gem, M35

Spring skies are dominated by an array of bright stars and distinctive constellations. In April and May, the zodiac constellation Gemini dominates the view to the west, gracing the sky with the twin stars Castor and Pollux, and guiding the curious observer toward a gem in the river of the Milky Way, which flows across the legs of the twin brothers.

The star pattern of Gemini is of the brothers Castor and Pollux standing side by side. The bright twin stars represent the heads of the twins, and the stars that are below Castor and Pollux trace out their bodies, arms, legs and even a foot. An advantage to viewing Gemini in the Spring is that the brothers are standing upright and are easy to see, whereas in other times of the year when Gemini is visible, the brothers are not in an easy-to-spot orientation, or are directly overhead, a difficult thing to see.

If you have binoculars, you can try to spot a very faint but beautiful star cluster called M35 near the foot of Castor, the twin on the right-hand side of the pair. You will need a star chart (click on the image above, or try this fine star chart) to locate this small circle of stars but if you have patience and a dark viewing location, you will know you have found it because M35 seems to glow in the view of your binoculars compared to the stars around it. The stars in M35 are quite distant, nearly 3000 light-years away (but still within the Milky Way galaxy).

Happy viewing, and good luck with M35!

Five Weeks of Planets in Conjunction

We are entering a period of time in which several planets are going to be in close proximity to each other, creating special alignments called "conjunctions." Mars, Mercury, Jupiter and Venus are all occupying the same region of the sky from our Earth-bound point of view, and as these planets and our own planet are all in motion around the Sun, the pattern we see in the sky changes quite a bit from one night to the next. At this time, all of these planets are emerging from the glare of the brightening dawn sky, appearing in the east just minutes before sunrise. Therefore, the initial conjunction on April 19th is best visible with the aid of binoculars. But this is just the start of a five week period in which these planets move very close to one another, creating a beautiful series of patterns for the early morning observer.

Our planet moves nearly 2 million miles per day in its orbit around the Sun. The planets are also moving at high speed around the Sun in their respective orbits. Mercury and Venus move the fastest relative to Earth, and because of their unique position inside the orbit of Earth, we see their changing locations in the early morning just before sunrise, or in the evening just after sunset. The other planets, including Mars and Jupiter for the next few weeks, move more slowly from our point of view and move more steadily from east to west from one morning to the next. I'll be posting a regular series of updates over the next month as the various conjunctions come and go. The important thing for the observer is to find a good eastern horizon, dust off the binoculars, and be ready to get up just before sunrise to see these cosmic alignments.

The Moon and two Star Clusters: Pleiades and Hyades

The Moon graces the last vestiges of the winter sky this week, as the waxing Moon splits two of the prettiest star clusters, the Pleiades and the Hyades. This will be an exciting sight for stargazers, one that will look particularly magical through binoculars. So mark your calendar for Thursday April 7th and watch the show unfold all week long.

When the Moon emerges from the New phase and starts its 29 1/2 day journey around the Earth, the first few days are always a treat, because the waxing crescent offers so much to see through a telescope or binoculars, and even without optical aid, the sight of the thinly-lit Moon and the glow of Earthshine always catch your eye.

On Thursday, the Moon moves past the Pleiades star cluster, one of the best known clusters in the sky because the stars in it are fairly bright and concentrated into a small space, creating a kind of glow in the sky. Around the bright star Aldeberan in Taurus is the open cluster called the Hyades. These stars are also a close grouping in the sky, but not as tightly arranged, so you don't get the same kind of glow. However, through binoculars this cluster offers much to see.

Use the graphic (above) to help you orient yourself this week. You will want an observing location with a clear western horizon, away from streetlights or other distractions, and good weather. If you get all these conditions just right, you have no excuse for missing this gem of a celestial lineup. And if you live in San Francisco, come join me at the Cal Academy for a personal tour :-)

KFOG Podcast - April 4, 2011

In today's podcast with Irish Greg of the KFOG Morning Show, we discuss the upcoming alignments of the Moon with star clusters in the evening sky, and I tell Greg about the upcoming festivities on Thursday in San Francisco at the Cal Academy's "NightLife" party celebrating Yuri's Night. It's quick and fun, so click here to listen.

Get Involved: Globe At Night, Lectures, California Academy of Sciences

There is always something to do if you are interested in getting a bit more involved in astronomy. Right now, you can learn at a lecture, attend a star party, or take part in a global project to record light pollution while learning about new constellations. Read on for details.

Here in San Francisco, the California Academy of Sciences hosts a lecture series on astronomy topics. The Dean Lecture Series features talks on some of the most riveting subjects in astronomy, and Monday April 4th is the next talk, presented by Joel Primack and Nancy Ellen Abrams, focuses on the most modern research in cosmology, that of Dark Matter and Dark Energy.

The California Academy of Sciences also has a fun event every Thursday night with its "NightLife" series, transforming the museum into a fun party. Each week has a theme, and next Thursday April 7th is Yuri's Night, an annual celebration of the first man in space. If the skies are clear, you can find me on the Living Roof giving star tours alongside the docents of the museum showing off planets, nebulae and the Moon through telescopes.

If you don't live in San Francisco, visit the Night Sky Network website to find lectures and astronomy clubs in your area.

The Globe At Night project is now in the second phase, inviting Citizen Scientists around the world to support the effort to raise awareness of light pollution, learn about the night sky in your neighborhood, and pay attention to details of the constellation Leo the Lion. Take part - it only requires a few minutes and is an eye-opening experience.

Vernal Equinox, Super Full Moon, and other astronomical musings

I enjoy sharing highlights of the sky with friends and have been blogging for several years now, pointing out events of astronomical interest here as The Urban Astronomer. I was surprised to see the excitement and questions about the Super Full Moon, the coincidence of nature that is leading to a full moon at perigee today. The fact that the general public is being scared into thinking something bad is about to happen is unfortunate, but the fact that people will be out tonight looking at the full moon is the good outcome that I wish for. Of course, there is absolutely nothing to be worried about. Every 29 days the Moon swings a bit closer to the Earth than other times of the month, and that pattern of perigee and apogee, full and new, repeats in a beautiful "super pattern" every 18 years, something now known (but likely not fully understood) by the many who are reading about the Super Full Moon being the biggest one in 18 years.

There are numerous patterns and cycles in the heavens. Tomorrow, March 20th, is the Vernal Equinox, the semi-annual moment when the length of the day is exactly 12 hours everyone on Earth. I like that dynamic, a twice-a-year event in which we are all given equal periods of sun above the horizon and below the horizon, regardless of your latitude, regardless of whether you are in the Northern or Southern Hemisphere. That is a moment of beauty in the grand annual rhythms of our home planet.

The pattern of lunar repetition that lasts for just longer than 18 years is also responsible for the cycle of lunar and solar eclipses that take place around the world. I witnessed a total solar eclipse in Europe in July 1999, and the celestial dynamics of that eclipse will exactly repeat in August 2017 when a wonderful total solar eclipse will sweep across the United States. For me, it will be a rare chance to be standing in the shadow of the Moon on the second passing of this particular alignment of Moon, Earth and Sun, one that will be far more dramatic and meaningful to me than any particular Super Full Moon you might encounter between now and then. But in the end, if you can find some meaning and solace looking up at the Moon tonight, savor the moment and mark your calendar for April 2029 when the conditions will align themselves and present you with a chance to relive this magic moment when you saw a particularly big and impressive full moon. That is something worth pondering, and the rest of the media hype you are hearing right now should be simply ignored.

Image courtesy NASA.