20 December 2009

Jupiter and Neptune Triple Conjunction: The Finale

For much of 2009 Jupiter and Neptune have been sharing the same space in the sky inside the Zodiac constellation Capricornus. Over the last few months they have moved progressively closer to each other and are now aligned in what is called a "Conjunction." In fact, the year 2009 saw this happen three times in a row, what astronomers call a Triple Conjunction, a rare and beautiful alignment of heavenly bodies.

I had not seen Neptune before this year's Triple Conjunction. A conjunction creates an opportunity to easily locate the less-bright planets Neptune and Uranus. These two are just dim enough to be invisible unless you (a) know exactly where to look, and (b) use optical aid such as a telescope or binoculars. With bright Jupiter as my guide, I was easily able to find Neptune lurking in the neighborhood, a beautiful blue pinpoint of light (see my previous post on the subject, Blue Neptune). The third of the three conjunctions of Jupiter and Neptune is even easier to find this week because the waxing Moon passes just above the duo on the evenings of December 20 and 21. In fact, the Moon makes a splendid guide to the planets each month, having just passed near Mercury a few days ago, and later in the month approaching orange-red Mars and yellow-white Saturn.

For a more detailed view of the paths of Jupiter and Neptune across the night sky check the diagrams on Martin Powell's excellent astronomy website. With these detailed charts, you can get a clear perspective on how these objects slowly make their way from one Zodiac constellation to the next every year. As Jupiter now begins prograde motion away from Capricornus, it will speed across Aquarius and into Pisces during the winter and by spring will be closing in on Uranus, where in 2010 we will have a Triple Conjunction of Jupiter and Uranus. Scroll down this page to see an excellent animation showing the motion of Uranus and Jupiter across the sky in 2010. The heavens never cease to offer up opportunities for discovery. Here's to clear skies!

12 December 2009

Geminid Meteor Shower 2009

One of the finest meteor showers of the year is the Geminids, so named because the meteors appear to emanate from the zodiac constellation Gemini. The shower peaks this year on Sunday evening December 13th and for us on the west coast of the United States, we will be well placed for the peak of the shower at 9:00 pm. Given that there won’t be any moonlight for this meteor shower, conditions are ideal for a good shower that can produce up to 120 meteors per hour in very dark conditions. For those of us who live in urban areas such as San Francisco, we will see considerably fewer meteors. Nonetheless, if you can get yourself away from streetlights, houselights and allow some time to adapt to the dark, you will see some Geminids.

Meteor showers that occur at the same time every year are usually caused by some kind of debris trail that the Earth intersects, showering the upper atmosphere with fine particles in an unusually intense period of time. Based on the way in which the Earth intersects the tiny bits of rock and dust, the meteors will all appear to originate in a single point in the sky, a point known as the "radiant." The Geminid meteor shower appears to originate in the constellation Gemini and as this constellation rises shortly after sunset, this particular meteor shower appears strong all night long, as Gemini treks across the sky from the east nearly directly overhead and then dropping into the west.

NASA has a great website talking about the origins of the Geminids, and Sky & Telescope Magazine has a very helpful article (written by Tony Flanders, an astronomer I've come to know personally) that is full of good tips for seeing the Geminids.

The weather outlook is always a challenge for December, and if the skies are clear they are most assuredly accompanied by a cold evening, so dress extra-warmly for the Geminids and enjoy.

09 December 2009

The Northern Sky: Circumpolar Stars and Polaris

I enjoy stargazing for many reasons, one of which is to get a sense of the motion of the sky as viewed from our vantage point here on Earth. As I have traveled around the globe, I've always tried to observe how the sky changes depending on where you view it from. One of the more fundamental things you can observe is the dynamic of the stars and constellations in the northern sky. For those of us who dwell in North America, we see the north star, Polaris, at the same height in the sky as we are located north of the equator. That is, for San Francisco at approximately 38 degrees north latitude, Polaris can be found due north, 38 degrees above the horizon.

For reasons you can read about in Wikipedia, Polaris does not move in the sky and therefore is never below the horizon. It is always fixed in the north above the horizon at the same arc as you are located north of the equator. However, the stars that surround Polaris also never dip below the horizon, but rather circle around Polaris in a 24-hour spiral that turns counter-clockwise. Long-exposure photographs show this effect very vividly.

Wonderful constellations and asterisms occupy the circumpolar region of the sky, including the Big and Little Dipper, Cassiopeia, Draco and Cepheus.

07 December 2009

Astronomy Gifts for the Holidays / Telescope Shopping

If you are considering a gift for someone who enjoys astronomy (or want to share something with a young person who might like to discover astronomy), I present to you my astronomy gift guide for the holidays.

A. Astronomy Gifts.

At my local astronomy shop here in San Francisco, Scope City, I asked manager Sam and salesperson Steve what they would recommend for the holidays. Telescopes are plentiful and that warrants a separate section of this blog post - see below. But aside from telescopes, there are binoculars of all types, excellent books, tools such as Star Finders and Planispheres, and new this year, the Sky Scout, a hot selling item from Celestron that has the astronomy hobbyist world abuzz. Point the Sky Scout at an object in the sky and it tells you what the object is and provides additional details. For another approach, you can open a door for astronomy for someone with a gift subscription to Astronomy Magazine or Sky & Telescope Magazine.

B: Telescopes - Top 5 Things to Consider When Buying a Telescope

A telescope is a powerful scientific instrument which, when well cared for, can provide years of viewing pleasure. Top brands include Meade, Orion and Celestron. However, there is a very wide range of options, quality and performance to choose from so before you buy a telescope learn a few things about them. Telescopes.com offers some useful background information, as does Astronomics.com with its informative pages. The Bad Astronomy blog has a helpful article, and this post provides a lot of detail for the telescope shopper. If you summarize all of the articles and if I draw from my own experience, I would recommend five things to think about when purchasing a telescope.

1. Consider Binoculars. They are easy to use, can be used at daytime as well as nighttime, cost less than a telescope, and are a good first test of one's interest in the night sky.

2. Buy quality. Avoid the cheap telescopes at the department stores. They not only have generally poor quality optics, but end up being a turn-off for those who purchase them. It's worth the extra money to get something you will enjoy.

3. Start simple. As much as the high-tech telescopes look like fun, they are still complex instruments that will need some degree of care-and-feeding when you use them. The most basic scopes, simple refractors on a lightweight tripod, take little time to set up and are the most simple to use. Also, a simple telescope is not as bulky and heavy to carry around. For kids, try out the Celestron FirstScope (see below).

4. Be comfortable. You really need to feel at ease with a telescope, so in the best case go to your local astronomy shop and try out a few. Scope City will let you take their binoculars and telescopes out in front of the store and do the "Safeway Test" to see how well you can resolve items in the aisles of Safeway grocery store next door.

5. Learn to use your telescope at your local astronomy club. Amateur astronomers like to help others to learn about astronomy. The San Francisco Amateur Astronomers and San Francisco Sidewalk Astronomers hold Telescope Clinics at their monthly star parties. These are excellent venues to bring your scope and learn to use it with astronomy enthusiasts. Check the Night Sky Network for a club near you.

C: For Young People.

Kids can benefit from astronomy gifts that are easy to use and make it simple to immediately start enjoying. I found numerous websites that showcase books for kids. Skymaps.com has a very well organized list of books for different age ranges, all the way from age 4 to young adult and educator. The Top 10 Astronomy Books for Kids on about.com offers some good choices. On the telescope front in 2009, Celestron premiered the FirstScope, an extremely simple telescope for kids that, from the reviews I've read, is surprisingly good quality yet very low price (about $50 at most outlets). It is an 'official product' of the International Year of Astronomy (IYA) celebration. But in the end I was most enamored with this simple recommendation from the Suite101.com blog:

"What children really need, more than 'stuff,' is for someone to take the time to stand outside with them on a starry night and point out planets and constellations. Teach them the sky. You can give coupons good for '1 Hour of Observing with Mom' or something similar."

Happy Holidays. Stay warm and enjoy the long dark nights.

02 December 2009

Get Involved: Astronomy Lectures, Star Parties and Telescope Workshops

There are many ways to get involved with astronomy here in San Francisco, or wherever you may be. A great resource for finding events in your neighborhood is the Night Sky Network, a resource chock-full of information from astronomy clubs across the United States. Just enter your location and you can find out what is happening in your area.

Here in San Francisco, the California Academy of Sciences has an astronomy lecture series called the Benjamin Dean Lecture Series. The next lecture in the series will be on Monday December 7th. The topic is Saturn, presented by Dr. Carolyn Porco, the director of the imaging team for the Cassini spacecraft that is orbiting Saturn. You can get tickets for the December 7th Dean Lecture online.

The San Francisco Amateur Astronomers (SFAA) have their monthly meeting at the Randall Museum on December 17th and their "City Star Party" on December 26th at Land's End in San Francisco. The City Star Party on the 26th (weather permitting) will be a great chance to bring out new holiday gifts such as telescopes and binoculars and learn to use them alongside amateur astronomers. The SFAA and the San Francisco Sidewalk Astronomers have free telescope workshops before each City Star Party but please RSVP to them at clinic@sfsidewalkastronomers.org if you plan to come on December 26th.

I hope to see you at an upcoming event!

22 November 2009

Jupiter and the Moon sparkle in the south

The next few days offer a chance to enjoy Jupiter and a waxing Moon together in the southern sky. I just showed this last night to a star party group and the view was exciting. The two objects sparkle in evening sky and provide a nice accent to an otherwise quiet part of the sky -- an area that is devoid of bright stars. So get out your telescope, enjoy a view of the craters of the Moon, and get a close-up of Jupiter and its moons while Jupiter is still bright and high in the sky after sunset.

16 November 2009

Leonid Meteor Shower 2009

The Leonids are reaching their peak tonight. This annual meteor shower peaks every time the Earth moves through the remnants of the comet Tempel-Tuttle. The meteor shower peaks when the Earth is directly intersecting the remnant streams ("filaments") from previous passes of the comet, and the peak for this year will be during the day of November 17th - unfortunate for those of us in the Western Hemisphere, but good for the night side of Earth at that time (primarily Asia).

Don't despair, however, as both the nights of Nov 16-17 and Nov 17-18 should provide some good meteor viewing even here in San Francisco. The Leonids appear to originate from the constellation Leo which rises in the east after midnight. As with all meteor showers, viewing gets better late at night into the early morning. Dress warmly and try to see a few. I'll be out early tomorrow to see what I can see.

09 November 2009

Moon, Saturn, Corvus, Virgo and Venus

Now that the sky is remaining dark later and later each day, I am enjoying the early morning interplay of Solar System and stellar objects. This week provides a series of lunar alignments with Saturn, the constellation Corvus, the bright star Spica in Virgo, and finally Venus -- if you have an exceptionally clear, low eastern horizon. Sunrise in San Francisco is from 6:45 to 6:50 am this week.

07 November 2009

Astronomical Pseudoscience and the 2012 Hoax

With the imminent release of the movie "2012" there is a blitz of pseudoscience on the internet that is helping to market the movie but is also unnecessarily fueling fears of "Doomsday." My view is that good science fiction is fun and entertaining, but the movie 2012 has opened a new chapter in viral marketing and the use of social media to misinform in the name of entertainment. The movie makes numerous (but inaccurate) claims of disaster based on changes to the Earth's magnetic poles, collision with planet Niburu, alignment of the Sun with the Galactic Center, and of course the prediction of this by the Mayan Calendar. Good science fiction is engaging and this movie could have been just that, but it is trying to do much more.

I've found a number of informative and helpful websites to counter the fears being propagated. NASA's astrobiologist David Morrison has been the primary spokesperson fielding questions for NASA from concerned citizens and has an excellent site. Andrew Fraknoi of the Astronomical Society of the Pacific rebukes a broad range of pseudoscience on the ASP website. The Universe Today has gathered a number of articles by Dr. Ian O'Neil that clarify the misconceptions associated with 2012. My favorite collection of information and debunking is on the 2012hoax website, which is a direct assault on the movie and the misconceptions.

I was particularly moved by the comments I heard by David Morrison on the SETI Institute podcast "Are We Alone" and by the 2012hoax website, both of which point out that vulnerable people will look at the 2012 marketing websites such as "The Institute for Human Continuity", the blog "After the IHC" and the blog "This is the End" as legitimate sources of information about doomsday, as a reason to give up, to commit suicide or worse. Anyone with a willingness to learn and understand real science won't be fooled by the blitz of pseudoscience. If you choose to see the movie, I am sure it will be engrossing. But don't think for a minute that it is based on real science. It's not even close.

There are genuine scientific projects underway that are on the lookout for real threats. Here is the NASA Near Earth Object program, cataloging and tracking potentially hazardous objects. Thank goodness for science!

04 November 2009

Dominating the Autumn Sky: Pegasus

In November, the nights grow longer and the sky changes rapidly. The Summer Triangle gradually fades into the west, and Orion and the winter constellations have not risen in the east to dominate the night sky. Instead, we see the less prominent (but no less beautiful) zodiac constellations of Capricornus, Aquarius and Pisces in the south, and directly overhead the large constellation Pegasus with the very distinctive asterism "The Great Square" in clear view. The sketch of the constellation Pegasus shown here is courtesy of the Battle Point Astronomical Association.

Pegasus is named after the Greek mythological character of the winged horse. Some constellations look a lot like their mythological namesake, but in this case I am always challenged to see the winged horse in the sky. But no matter, the shape of Pegasus is distinctive, and the Great Square makes it easy to find. This time of year Pegasus is high in the eastern sky after sunset and it moves almost directly overhead by 10 pm. I was out in my backyard a few minutes ago looking at it and to best see it I had to sit back on a chair. The Great Square is so striking because, yes, it is indeed nearly a perfect square, but more interesting is that there are virtually no other bright stars inside the square to disturb the shape. All around Pegasus, however, are a good number of bright stars, some of which form the head and feet of the winged horse, while the stars on the north side of the Great Square are actually part of Andromeda. In fact, I use Pegasus to help me find the constellation Andromeda and that points us to the Andromeda Galaxy (but that is a topic for another post).

For an excellent set of illustrations and tour of the Autumn sky, visit this webpage from the Smoky Mountain Astronomical Society.

01 November 2009

Close Encounter of the Pleiades and Moon

The Pleiades is one of the most beautiful star clusters in the sky. In Autumn it rises during the evening and its distinctive glow shines even for urban dwellers. The Pleiades, also known as M45 (from the Messier Catalog), is a collection of relatively young stars (only 100 million years old!) that shine with a blue color due to their hot temperature. The Pleiades are also known as the Seven Sisters and there is plenty of mythology describing each of the seven sisters. Despite the "Seven Sisters" mythology, most people see six stars when they look out at the Pleiades and describe the shape of the asterism as a small Little Dipper. Random fact: the Subaru car company logo is made up of six the stars, Subaru being the Japanese term for Pleiades.

This week on Tuesday evening the full moon passes very close to the Pleiades and in more southerly latitudes it actually occults (blocks out) several of the brightest stars in the cluster. For those of us in San Francisco, the evening of November 3rd should be especially interesting if you view the Moon through binoculars or a telescope. You will be able to notice how fast the Moon moves past the stars of the Pleiades. Although the very bright light of the full Moon will drown out nearly everything around it (including the blue nebulosity of the dust surrounding the Pleiades), all will be clear when you look closely with binoculars or a telescope.

25 October 2009

Jupiter and the Moon dominate the sky

For the next few evenings Jupiter and the Moon put on a show as they brighten up the southern sky. Jupiter is in Capricornus moving gradually eastward across the constellation. The Moon, just past first quarter phase, is also speeding across Capricornus and will appear very near to Jupiter on Monday evening October 26th.

Jupiter will remain a brilliant light high in the southern sky for the remainder of 2009. I enjoy the close-up view of the planet through a telescope or binoculars because you can see the four Galilean satellites, moons that are big enough to see with just 10 or 20x magnification, moons that move so quickly that you can detect the change of position of the four Galilean moons with respect to each other in just one evening of watching.

24 October 2009

The Urban Astronomer LIVE!

I recorded a few videos of myself talking about star parties, what to see in the night sky, how to use a telescope, and more. They are short and to the point. I haven't done a lot with video up until now, but I think it will be a nice way to share some basics on observing and astronomy. So if you have a few minutes to spare, click here for the Urban Astronomer LIVE!

22 October 2009

Get Involved: Galilean Nights Star Parties in San Francisco

As part of the ongoing International Year of Astronomy (IYA), this weekend, October 23-25, is being hailed "Galilean Nights" in honor of the Italian scientist who used a telescope to open a new era of understanding of the heavens. Astronomy clubs around the world are hosting star parties and inviting the public to take part.

The San Francisco Amateur Astronomers (SFAA) will hold two star parties on Saturday October 24th, one in the city of San Francisco and one at Mount Tamalpais in Marin County. I have often blogged about the SFAA events on Mt. Tam, where there are great lectures by professional astronomers and scientists as well as star gazing through amateur and professional telescopes. This month the lecture is at 7:00 pm with Professor Michael Dine of UCSC. I love to attend these events and share the night sky with attendees. This month, however, I'll be at the "City Star Party" (weather permitting) at Lands End in San Francisco. This event will start at 6:30 pm at the end of El Camino del Mar just off Point Lobos above the Sutro Baths ruins.

If you don't live near San Francisco or Marin, you can check out the Galilean Nights website for details of an event near you. See you under the stars.

19 October 2009

Galileo's Findings 400 Year Ago: KALW Broadcast

I was a guest on the Crosscurrents Program on KALW Radio (91.7 FM in San Francisco) today talking about Galileo.

Listen in and learn a few things about the his discoveries, fundamental concepts that changed our understanding of the world around us. This is what the International Year of Astronomy (IYA) is all about.

12 October 2009

Planetary Motion

The morning sky continues to be a busy place, showcasing just how much action is taking place in the Solar System. Saturn, a relatively slow moving outer planet is gradually rising up in the east, emerging each morning a minute or two earlier so that it will soon be a true morning star. As it graces the dawn sky just ahead of the sunrise, it is encountering the two fast-moving inner planets, Venus and Mercury. This week they have close encounters and beautiful alignments that will be a sight to see. The illustrations provide a sense of how far Venus and Mercury move over the course of just a few days. The passing of the waning Moon on the mornings of the 15th and 16th add a nice touch to an already impressive lineup of Solar System objects.

04 October 2009

Morning Spectacle

Three planets make a nice showing in the early hours of the morning this week, with Mercury and Saturn having a close encounter. Autumn mornings are particularly interesting here in San Francisco because the weather is generally more reliable and the first light of dawn comes so late in the morning -- right now around 6:45 am with sunrise around 7:15 am. The view in the image shows what you can expect to see this week as Saturn and fast-changing Mercury line up on Thursday morning October 8th. All of this will stand in stark contrast to bright Venus, the brilliant beacon dominating the eastern sky in the morning.

Later this week there will be another amazing event in the morning sky. Stay tuned!

25 September 2009

"Journey to the Stars" at the California Academy of Sciences

The latest show at the California Academy of Sciences (CAS), "Journey to the Stars," premiers on September 26th. The CAS, in conjunction with the American Museum of Natural History (AMNH) in New York, created an excellent visual and scientific experience for all ages, yielding an impressive work that both teaches and amazes with its sharp, detailed images of the life cycle of stars.

The Morrison Planetarium at the CAS is an all-digital theater with a 75 foot dome that transforms itself into the night sky and transports the audience to the far reaches of the galaxy. I continue to marvel at the way in which new technology and research are being combined by the AMNH and CAS to bring the latest astronomical and cosmological discoveries to mainstream audiences in a way that makes the science interesting and vivid. For example, during "Journey to the Stars" I was very impressed with close-up visits to the Orion Nebula and Helix Nebula in which the audience gets a close-up view of the depth and breadth of these star-forming regions of space. Classroom learning about star formation is one thing; seeing the amazing photographs such as the Pillars of Creation from the Hubble Space Telescope is another; but the interactive view of these places with the advanced digital imaging that you see in "Journey to the Stars" is, in my view, extraordinary.

The show runs many times daily and I strongly urge anyone with an interest in science and astronomy to head out to Golden Gate Park to take in this riveting show.

14 September 2009

Brilliant Venus shining in the morning sky

Venus, the brilliant morning "star", dominates the morning sky. During the next week it will have a close encounter with the waning Moon and then a very close alignment with Regulus, the brightest star in the zodiac constellation Leo. Now that the sunrise is getting later each morning, it's not so unusual to get up when it is dark enough to see brilliant Venus in the eastern sky. The diagrams will help you to find your way in the eastern sky.

07 September 2009

Get involved: AANC astronomy lectures and star party on September 12

Here's a chance to dive into astronomy and hear from the scientists that are making news right now. The Astronomical Association of Northern California (AANC) is opening the first day of its annual meeting to the public on Saturday September 12th at the Westin Hotel at SFO in Millbrae. The day features a broad range of talks about astronomy, from imaging of the heavens through the Hubble Space Telescope, to the Search for Extraterrestrial Intelligence (SETI), to the upcoming NASA Lunar Impactor mission (LCROSS mission), and the history of the telescope. Also there will be telescopes for solar observing during the day and a star party in the evening (lead by yours truly). Register online - high-school age students are Free. Visit aancstars2009.org for details.

04 September 2009

Saturn has no rings!

If you could get a good telescopic view of Saturn today, you would find that it has no rings. At least that would appear to be the case for several days as another rare phenomenon takes place in the Solar System. Of all of the beautiful objects in the sky, Saturn is one of those wonderful heavenly targets that can be seen from cities and country, from spacecraft and flying telescopes, and always impresses the viewer. The second largest planet in the Solar System, Saturn has the largest and most distinctive ring system (Jupiter, Uranus and Neptune also have ring systems). The detailed photographs sent back to Earth from the Voyager and Cassini spacecraft and the Hubble Space Telescope have given us stunning perspectives into the depth and intricacies of the Saturnian ring system.

Saturn's ring system is very thin (less than 50 feet thick), and when viewed 'edge-on' from Earth it is virtually invisible. Saturn, like Earth, has a tilt in its rotation such that it has seasons as it moves around the Sun in its 30-year orbit. Consequently, every 15 years we see the ring system from the side and for a short while it disappears from view altogether. Although the ring system is very thin, it is extremely wide -- about 170,000 miles across, making the system even bigger than Jupiter!

Saturn is currently moving its way westward across the constellation Leo the Lion and is not visible due to its proximity to the Sun in the morning sky. It will gradually emerge from the glare of the dawn and be visible before sunrise. By the end of the year it will be rising in the east just before midnight and by next spring will be a gorgeous evening object with its ring system back in view. Until then, enjoy Jupiter and its fascinating moon system -- except when they aren't there!

02 September 2009

Jupiter has no moons!

Tonight Jupiter will have no moons. At least that will appear to be the case for a short while, as a rare phenomenon takes place in which all of the four bright moons of Jupiter will not be visible for viewers on Earth.

Any night of the year that Jupiter is visible, you can usually spot several of the four Galilean moons. Io, Europa, Ganymede and Callisto are big enough that they are easy to find in a telescope or even binoculars. The inner three moons, Io, Europa and Ganymede orbit Jupiter very rapidly, in 2, 4 and 8 days respectively. So on any given night the relative position of the four moons changes and the pattern of the four moons around Jupiter - from our point of view - is always in flux. The above image from Sky and Telescope Magazine helps to illustrate this.

To make things more interesting, as a moon passes directly in front of Jupiter or behind it (or in the shadow of Jupiter) it becomes invisible for a few hours. This evening from 7:00 to 12:00 pacific time, the moons will be invisible for some period of time, with all four moons being out of view from 9:43 until 11:29 pacific. If you have a telescope or binoculars, use them to catch the changing pattern of the moons and witness this unusual alignment.

Jupiter, by the way, can be easily spotted tonight as the bright "star" in the east near the full Moon.

24 August 2009

The Milky Way and the Galactic Center

At the SFAA star party a couple nights ago on Mt Tam, the conditions were very clear and dark and we had a nice view of the Milky Way. With an excellent southern horizon, we could see all of Scorpius and Sagittarius and as my daughter and I were giving star tours to guests at the star party, I was happy to point out these two constellations and note that the center of the Milky Way was in the vicinity of the tail of Scorpius and the "teapot" of Sagittarius. This is called the "Galactic Center" and is the central bulge of the Milky Way Galaxy.

Looking toward the galactic center, however, you don't see a huge ball of light. That is because there is a massive dust cloud that lies between the Sun and the galactic center. Too bad for us, because it would be quite amazing to see the center of our own galaxy. Nonetheless, there is much richness in the sky near the galactic center and even in city lights you can begin to see some of that beauty if you use a pair of binoculars. Standard 7x35 or 10x50 binoculars can substantially increase the amount of light you can see, and that means you can begin to discern the stars and shapes of deep space objects such as the Lagoon Nebula or the Swan Nebula. Take out binoculars and point yourself south and see if you can start to see some of the wonders that are at the heart of the Milky Way.

17 August 2009

Get involved: Astronomy events in August

San Francisco Amateur Astronomers (SFAA) are hosting two events in the coming days, both open to the public at no charge.

The monthly meeting of the SFAA takes place on Wednesday evening August 19th at 7:30 pm at the Randall Museum in San Francisco. From the SFAA: "Jack Welch of the Robert Ferguson Observatory in Sonoma gives a presentation on how we measure time and how time measurement is handled in various astronomy and space situations. Welch will explain how our understanding of time measurement has changed as technology and theory have developed, and will explore some of the special challenges satellites and spacecraft have when it comes to timekeeping."

The monthly SFAA event on Mount Tamalpais in Marin features a speaker and a public Star Party. It takes place at the Mountain Theater on Mt. Tam on Saturday August 22nd at 8:30 pm (lecture) with the star party immediately following the lecture. From the SFAA: "Dr. Anthony Coloprete of NASA-Ames will fill us in on all the details of the LCROSS mission. Two spacecrafts are on their way to the moon, and the impending impact on October 9 will be visible even with small scopes from Earth. Why crash into the moon? Dr. Coloprete’s talk 'Prospecting for Water on the Moon' reveals all."

The SFAA welcomes all to their events each month. I hope to see you at one of these events.

10 August 2009

Perseid Meteor Shower 2009

It's August and that means its time for the annual Perseid Meteor Shower, this year reaching its peak on the evening and through the morning of August 11-12. Meteors are visible just about any night of the year, but throughout the year there are periods of intense activity in the sky ("meteor showers") because the Earth travels through a point in its orbit where there is a higher amount of space dust, rocks and other particles that enter the atmosphere at tens of thousands of miles per hour and burn up, creating bright streaks across the sky.

The Perseid Meteor Shower is going to be harder to see in 2009 because of the bright Moon that rises at 10:40 pm in San Francisco. For the city dweller, however, the shower is not much worse because of the bright Moon, as our city lights obscure many meteors anyhow. So the best you can do is simply enjoy the shower the evening of August 11th from wherever you are in the city. Pick a darkened comfortable spot. Lay back on a blanket and point your feet to toward the north-east and look around the sky. As the evening wears on, the origination point ("radiant") of the meteor shower rises in the north-east. This area is near the constellations Perseus and Cassiopeia as shown in the illustration to the right.

This year there will be a possible jump in the number of meteors as the Earth passes through a denser-than-usual filament of dust from the remnants of comet Swift-Tuttle. That will happen around 1:00 am pacific time on the 12th, so if you are up late you might just see a more intense period of meteor activity. Throughout the entire evening, the Moon will remain the one bright light everyone cannot escape, so when it rises just point your gaze in another direction and keep your eyes on the sky. And stay warm!

If you want to see a good meteor shower this year that won't have moonlight in the way, look ahead to December 14th when the Geminids will peak at an even higher rate than the Perseids. However it will be considerably cooler and the weather is less predictable at that time.

08 August 2009

Get involved: AANC astronomy lectures and star party in September

Save the date: September 12th in Millbrae (just south of San Francisco near SFO). The Astronomical Association of Northern California (AANC), along with the Astronomical Society of the Pacific (ASP), are sponsoring the AANC annual meeting and has designated Saturday September 12th as a day open to the public. The day will include lectures by expert astronomers and astrophysicists, solar viewing through telescopes during the day, brown bag workshops, exhibits by local astronomy clubs and dealers, and an evening star party. Families are welcome and children are admitted free. Check out the details on the AANC Annual Meeting 2009 website and register now. I'll be taking part throughout the day and I'll be supporting the evening Star Party as well. More on these topics soon.

24 July 2009

The Summer Triangle

One of the brightest objects in the nighttime sky each summer is called the Summer Triangle. Rather than being a single constellation, the Summer Triangle is an "asterism," a grouping of stars that make an interesting pattern but are not themselves a single constellation. The Summer Triangle is, as advertised, a very distinctive triangle of three very bright stars that form a 30-60 right triangle. The three bright stars are Vega, Deneb and Altair. With three stars at magnitude 0 or 1, the Summer Triangle shines through even light-polluted city skies.

If you have darker skies, the Summer Triangle is a quick guidepost to locating some of the most interesting objects you can see with binoculars or a telescope in the Milky Way. The image to the right is taken from the website of the Great Smoky Mountain Astronomical Society. I like their web images because they present a very easy-to-follow guide to the most interesting objects in the part of the Milky Way that passes through the Summer Triangle, including double stars, nebulae, star clusters and the patterns of the three constellations that include the three bright stars of the Summer Triangle: Lyra, Aquila and Cygnus. For another description of the same objects, try this page from the Royal Observatory in Greenwich.

Use your binoculars or a telescope - even if you are in a big city - and see how much of these constellations you can identify and how many of the interesting objects you can find lurking in their midst.

Amateur Astronomy on KALW Radio / SFAA Star Parties

I like blogging about astronomy because I want to get the public motivated to spend a few minutes out under the stars instead of staying inside at night. To that end, I've been able to extend my reach by being a guest on KFOG radio from time to time. This week KALW, public radio at 91.7FM in San Francisco, broadcast a feature story on the San Francisco Amateur Astronomers at one of their Star Parties on Mt Tam. It's great radio and it gives you a good perspective on what you do at at Star Party. KALW also recorded a brief interview with yours truly talking about the night sky. I used to be a radio DJ years ago and it's a real pleasure to have the opportunity to get in front of a microphone and reach out to the public over that medium, be it on KFOG or KALW.

The next chance to meet the San Francisco Amateur Astronomers at a star party on Mt Tam is this Saturday night, July 25th. The evening opens at 8:30 pm with a lecture by Dr. Natalie Batalha of San Jose State, talking about a NASA mission called Kepler. The Kepler Mission is looking for habitable planets that are orbiting other stars in the Milky Way. After the lecture, the SFAA will have telescopes for public viewing of the heavens. Unfortunately I will miss the lecture and star party on Mt Tam this month, but fortunately I'll be near Lake Tahoe enjoying dark skies and hosting some star parties there. More on that in a future post.

22 July 2009

Total Solar Eclipse in Asia

Today a large part of the eastern hemisphere experienced a solar eclipse, and along a narrow band of Earth viewers were well positioned to experience a Total Solar Eclipse, a rare and beautiful phenomenon. Unfortunately for most, the summer weather was miserable and the skies were cloudy - something that eclipse viewers (and eclipse chasers like me) don't want. Still, there was some limited visibility from a few observing sites. The tour group organized by Sky & Telescope Magazine saw a "murky" total solar eclipse. Better than none, I suppose.

For those of you wishing to see one closer to home, you'll have to wait until 2017 for a Total Solar Eclipse in the USA.

15 July 2009

KFOG Broadcast: July 15, 2009

Moon, Pleiades, Mars and Venus

The next few mornings provide a great chance to see close alignments of planets, the Moon and the easy-to-spot, beautiful star cluster known as the Pleiades. Click on the illustration (at the right) for a detailed view of the spectacle in the eastern pre-dawn sky, especially the changing location of the Moon each morning as it wanes from last quarter to a thin crescent.

12 July 2009

SFAA Astronomy Lectures: Spitzer Telescope, Kuiper Belt

Every month the San Francisco Amateur Astronomers (SFAA) host a lecture by an expert in the field of astronomy. In June, the guest was Dr. Dana Backmann of the SOFIA Project and SETI Institute. Dr. Backmann spoke about the Spitzer Space Telescope and the detailed research underway to understand and photograph Exoplanets. These are planets orbiting stars outside of our own Sun, such as Epsilon Eridani, Fomalhaut and Vega. Of the 350 stars being studied by the Spitzer Space Telescope, 20% of them have "Kuiper Belts" where Neptune-like planets can be found.

This month the San Francisco Amateur Astronomers meeting and lecture takes place on Wednesday July 15th at 7:30 pm. The lecture features Dr. Eugene Chiang, Associate Professor of Astronomy and Earth & Planetary Science at UC Berkeley, in a talk entitled "The Tenth Planet & Beyond." Dr. Chiang will focus exclusively on the Kuiper Belt, the part of the Solar System beyond the orbit of Neptune that includes over 1000 icy, rocky objects, including one bigger than Pluto.

The SFAA lectures always take place at the Randall Museum in San Francisco and are open to all ages (although many of the topics are oriented toward an adult audience). Bring a friend and take advantage of the chance to get a truly in-depth perspective on a range of topics in the field of astronomy.

One additional note: a traveling display of astronomical photographs from space missions are on tour and currently at the California Academy of Sciences in Golden Gate Park in San Francisco. The display, called "From Earth to the Universe (FETTU)" will remain at the CAS until September and then move to the Tech Museum in San Jose. The FETTU exhibit showcases the varying spectra of light and how scientists learn by studying the universe at wavelengths of light other than the visible spectrum, something that can help the public to better understand the SOFIA Project.

08 July 2009

iPhone apps: Star Walk, Moon Map Lite

I love my iPhone. There are many reasons for this, not the least of which are the nifty astronomy apps that are available for the iPhone. These apps bring a universe of information (pun intended) to my fingertips anytime and anyplace.

I've been using these apps while enjoying the rare clear evenings here in San Francisco this summer and will start posting short write-ups of these apps. Although these are not definitive, elaborate product reviews, I wanted to offer some cursory thoughts on a selection of astronomy apps for the iPhone. Here are two, Star Walk and Moon Map (Lite).

Star Walk: ($4.99) I am delighted with this application and have put it to work under different circumstances and in different settings, high on Mt. Tam, in the coastal redwoods where the skies were dark, and in my own backyard in San Francisco under the glow of city lights. Dan Schroeder has an excellent website with a complete review of Star Walk including screenshots.

My personal experience is that the application provides the detail needed while enjoying an evening under the stars. I used it extensively to accurately locate all the stars of constellations when I simply want to know the exact configuration of Bootes or Virgo or Centaurus (as noted in my Mt. Tam blog post). I also used Star Walk with binoculars to find Messier objects in Canis Venatici and Ursa Major this evening and the level of detail was just sufficient to help me to correctly identify these objects.

As with any iPhone application, there is tremendous flexibility to zoom in and out, something that makes map reading feasible on such a small screen. Having all of this detail in my pocket, ready to go at any time, is a very powerful tool for the casual observer as well as the seasoned amateur. My test of technology, hobby toys and computer applications is whether I actually get them out and use them when I should. With Star Walk, I find I am using it more and more often to give me deeper insights into the night sky.

Moon Map Lite: This is a free application (there are standard and "pro" versions that cost a few dollars) and it does just what it claims, providing a nice detailed map of the moon that you can scroll and zoom. The creator of Moon Map has a nice webpage showing all three versions of the application with short demo videos.

Earlier this week the full moon dominated the sky and I spent some time trying to use Moon Map Lite to help me identify some of the major features of the moon. I've not tried to identify more than just a few features of the moon in the past, so I figured this would be a chance to see if I could learn some new craters and seas.

To my dismay, I found this to be considerably more challenging than expected, primarily because the full moon is illuminated in a way that "drowns out" some of the key features of craters and makes them look quite a bit different than the excellent maps in Moon Map. However, I don't blame the Moon Map application for this, but rather my limited attempt to use it during only one phase of the moon. I will try using Moon Map to learn more of the moon's features when the moon is at different points in its orbit, looking for additional details through the telescope that might be easier to see when the sunlight strikes the moon from different angles. And who knows, I might just spring for $2.99 to get Moon Map Pro :-)

Coming soon: I'll review more iPhone apps including Distant Suns, Iridium Flares, ISS Visibility and iSolarScape. If you want to read an excellent group of reviews of star-map applications and see a very helpful comparison chart, look at Dan Schroeder's webpage comparing seven different iPhone apps.

04 July 2009

International Space Station Marathon

When I host a star party or head outdoors in the evening, I like to check the status of satellites such as the Iridium communications satellites or the International Space Station (ISS). When they are visible, I like to point them out to friends. I marvel at these satellites in particular because they are (a) bright enough to see even with bright city lights, and (b) are well tracked and therefore predictable.

For the next few weeks the International Space Station will be particularly well positioned in its orbits around the Earth to be seen much more often than usual - even multiple times a day each week - throughout the month of July! I am looking forward to the graceful swing of the ISS across the sky, speeding at over 17,000 miles per hour overhead. NASA is calling this especially interesting period of time the Space Station Marathon and I think it will be great. Next week the Space Shuttle Endeavour will launch and link to the ISS to make the flyby even more interesting.

Here is the timetable for ISS visibility over San Francisco. If you don't live here, you can use the link on the right hand side of this blog to get to the general purpose ISS locator ("Space Station/Satellite Sighting").

30 June 2009

Scorpius now in view

The summer constellation Scorpius is now center-stage in the southern sky. It's always a treat to see the distinctive shape of Scorpius with red supergiant star Antares glowing in the sky. Through binoculars Scorpius is great because of an abundance of deep-sky objects in and near the constellation. And this week there is an extra treat as the moon passes through.

21 June 2009

Star Party on Saturday 27 June

This Saturday is a chance to hear a great lecture and enjoy star gazing with the San Francisco Amateur Astronomers (SFAA) for their monthly star party on Mt. Tam. This month, Professor Lynn R. Cominsky of Sonoma State University is giving a lecture at 8:30 pm at the Mountain Theater. Her topic will include "blazing galaxies, intense stellar explosion and super-massive block holes" and should be quite captivating. Afterwards, the SFAA will set up telescopes for public viewing of the universe and there is a lot to see this time of year. The Moon will be a lovely crescent, Saturn is visible, and many deep space objects such as star clusters and nebulae will be on display. And if all goes well, I'll be there pointing out constellations with my trusty green laser pointer.

Hope to see you Saturday night - above the fog.

10 June 2009

Eerie Moon

We all know what the Moon looks like when it is in its early phases, waxing from a thin crescent over a two-week interval of time through first quarter and then to full moon. Although many people might not be able to explain exactly which way the "horns" of a crescent moon are pointed, it's something that you just know is right when you see it. For us living in the Northern Hemisphere, the horns of the young crescent moon point left and up when you see the moon in the western sky after sunset. That is, they point primarily south (left) and up (east) because the moon is being illuminated by the setting sun -- which is typically to the lower right (northwest) of the crescent moon. If you suddenly saw the horns of the crescent moon pointing the other direction, you might find it strangely discomforting. I certainly would!

Each month as the moon wanes from full moon to last quarter to a thin crescent in the morning, the orientation of the crescent reverses compared to the first 14 days of the lunar cycle. But because these phases are visible late in the night and in the early morning, there are generally fewer opportunities to see the moon in these phases. When I am up late at night or very early before sunrise and I see an old moon in the sky, the reversal of the orientation of the horns always throws me off. This week and weekend if you are up late at night or early in the morning you can take note of this as the waning moon passes Jupiter (see image) and continues eastward in its path, slimming to a thin crescent by June 18-20. Sky and Telescope Magazine called the waning gibbous late at night an "eerie moon" and I can appreciate why they would call it that. Whenever you see the moon, be it a slender evening crescent just starting its 29-day cycle, or a bold full moon lighting up the night, or a waning gibbous, think about the view and how it makes you feel. If you can start to gain a familiarity with the phases of the moon, you will find it does indeed evoke different feelings depending upon which phase it is in.

04 June 2009

Above The Fog: Star Parties on Mt. Tam

It's been foggy in San Francisco. Really foggy. It seems like we have one clear night and six foggy nights per week lately and that is not what an Urban Astronomer likes. So it was with delight that I drove myself and my daughter to Mt. Tamalpais last Saturday for the monthly lecture and star party put on by the San Francisco Amateur Astronomers (SFAA). The Mt. Tam lecture series has been going on for many years and features a wide range of speakers from different areas of astronomy and cosmology.

Following each month's lecture, the SFAA hosts a star party featuring a collection of telescopes, some homemade by SFAA members, pointing out the wonders of the night sky. Despite the foggy conditions in San Francisco and Marin, Mt. Tam is almost always a great vantage point because you are literally "above the fog" and despite the proximity to the city lights of the Bay Area, the viewing conditions on Mt. Tam are quite good. Last Saturday was no exception and the view of the first quarter Moon, Saturn and the spring and summer constellations was great. My daughter and I used an iPhone application called "Star Walk" to help us to identify the fainter stars in Libra and Virgo, to get a full picture of the big summer constellation Ophiuchus, and to even identify part of Centaurus. Using the "Star Walk" application we were able to see that the view from Mt. Tam toward the south was good enough for us to see the upper half of Centaurus and even though we could not see our nearest stellar neighbor, the Alpha Centauri system, we felt like we were nearly there. In fact, it was very interesting to see on my iPhone that the Southern Cross was only a few degrees below the horizon at that moment and even though we can never see it from 37 and 38 degrees north latitude (the Bay Area), I felt like I was *almost* there. I guess I need a vacation at a more southerly latitude ...

27 May 2009

Blue Neptune

A first for me: Early this morning before sunrise was the first of three conjunctions between Neptune and Jupiter. The rare "triple conjunction" started this morning with a close passage of Jupiter near Neptune in Capricorn. The separation was less than half a degree (less than a moon-width) and the difference visually between giant Jupiter and its four moons and blue Neptune was dramatic. Neptune looks essentially like a dim blue star through binoculars -- and is invisible to the unaided eye.

I had never taken the time to look for Neptune in the past. Because it is so dim and nearly impossible to resolve to anything but a pinpoint of light, I had never been motivated to seek it in a field of dim stars. But with Jupiter as my guide, it was an easy find and a magical moment to see those two solar system objects in one field of view. The alignment of two very distant planets - one 450 million miles away, the other almost 3 billion miles away - in a compact cluster less than half a degree apart was nothing short of remarkable. Now that the two planets have lined up once, they will soon reverse course and move in retrograde motion across the sky and will have the second conjunction on July 13th. Then they will return to prograde motion and have their final conjunction on December 20th. This long slow process is rare indeed, but as Jupiter speeds eastward away from Neptune after December 20th, it will soon arrive near to Uranus and will have a triple conjunction with Uranus starting in June 2010. I'll be sure to catch that one as well - because - yes, because I haven't ever seen Uranus either!