31 December 2013

Quadrantid Meteor Shower 2014

Quadrantid Meteor
The annual Quadrantid meteor shower is underway, bringing its lovely blips of light streaking across the sky. This shower takes place over several days but has a strong peak the morning of January 3rd. As is the case with all meteor showers, you want to be in a dark location (or if you live in a city, in an unlit location such as a backyard or park or beach), and you need to give yourself 5-10 minutes for your eyes to adapt. You'll want to dress extra-warm and use a sleeping bag so you can relax on your back and enjoy the view skyward. There is no particular direction you need to look; the best view of any meteor shower is directly overhead. Universe Today and EarthSky have helpful articles for further information.

The Quadrantids are the first of many meteor showers in 2014. I hope you can see many of them.

Image linked from stefanoderosa.com photography website.

28 December 2013

Super New Moon and Perigean Spring Tides

Charlie at Ocean Beach
I live on the west side of San Francisco near Ocean Beach and enjoy seeing the impact of the Sun and Moon firsthand. I watch the seasonal changes to the high and low tides at the beach and note the relative impact of the changing phases of the Moon and the subtle influence of the Sun's near and far approaches to the Earth. These changes are compounded on January 1st and the impact on tides will be dramatic.

On January 1st, we'll experience the first of three "SuperMoons" for 2014, but you won't be able to see the first one as it will be a Super New Moon. Previously we had some beautiful Super Full Moons, glorious to watch as they rise and dominate the night sky. But a Super New Moon is so close to the Sun that it's not visible at all. However, it's influence is felt in our oceans and on full display in the tidal highs and lows. On January 1st, we see the convergence of three separate influences on the tides:

- the larger than usual Spring Tide that takes place each month at New Moon
- the influence of "Perihelion" when the Sun is nearest the Earth for the year (specifically on Jan 3)
- the influence of "Perigee" when the Moon is nearest the Earth for this lunar cycle

As these three things line up and reach peak on January 1st, we will see the highest high tides and lowest low tides of the year, also known as a Perigean Spring Tide. At Ocean Beach we will see a +7 foot high tide around 10:30 am, and a -1 foot low tide around 4:30 pm, something that dries up the shore just below the famous Cliff House landmark at the edge of San Francisco. I'll be there!

There is an interesting project called the California King Tides Initiative that seeks to document very high tides, in an effort to evaluate the impact of global warming on coastal communities. When we have Super Moons, the tides are usually higher than usual as well - a chance to experience a King Tide.

15 December 2013

Comet Lovejoy in the morning

Comet Lovejoy
Despite the fizzle of Comet ISON, another comet is nearing its closest approach to the Sun and is assuredly *not* going to burn up. Comet Lovejoy 2013 is not a bright comet, but it is a beautiful sight with a long tail as it nears the Sun. Lucky for this comet, it won't be a "sun grazer" like ISON, so there is no threat of imminent disintegration. You'll need binoculars or a telescope to see it in any detail, and it will be best seen toward the end of December when the moonlight will interfere less with the night sky.

This article by Astro Bob contains good information on finding Lovejoy in the morning sky, presently in the constellation Hercules.

Image credit: Gerald Rhemann.

28 November 2013

Comet ISON at Perihelion on Thanksgiving Day 2013

Today is the big day when ISON flies by the Sun ("perihelion"), and all eyes are on NASA's SOHO spacecraft that is watching the event first-hand.

For up-to-the-minute web resources, I recommend the following sites.

Google Hangout with NASA
SpaceWeather.com
Sky & Telescope
EarthSky.org
NASA Comet ISON Observing Campaign

As of 7:00 am pacific time, it seems that the brightness of Comet ISON dropped somewhat, as reported on Spaceweather.com and Sky & Telescope.

There is concern that the very active Sun could release a Coronal Mass Ejection (CME) as ISON is at closest approach and this would be a very substantial threat to ISON's survival.

As of 8:30 am pacific time, there is speculation that the brightness is falling rapidly indicating that the comet is considerably vaporized and might not survive perihelion.

As of 10:00 pm pacific time, it's possible that a small part of the comet remains intact, but overall it seems that the comet has been mostly decimated in the trip around the Sun.

As of November 30, it looks like Comet ISON has really disintegrated. Very sad indeed. But it was a fun to have all of the excitement and close watching of this rare event. Here's to the next big comet headed our way!

26 November 2013

KGO TV 7 News Feature - Nov 26, 2013

I did a feature story on Channel 7 Evening News today with Wayne Freedman on Comet ISON. Click here to view.

KFOG Broadcast - Nov 26, 2013

Much discussion about Comet ISON and related 'cosmic' topics with Greg and Mudd on the KFOG Morning Show. Click here to listen. 

24 November 2013

KGO Broadcast - November 24, 2013

Today's show on KGO featured a lengthly discussion about Comet ISON, asteroids, space travel and the search for extraterrestrial intelligence. Click here to listen.

23 November 2013

Planets and Comet ISON

Lately while trying to view Comet ISON, I have been up early looking at the sky and enjoying the view to the east as stars and planets emerge from their sojourn around the Sun and start their trek across the sky. Saturn had been an evening sky object in the summer, disappeared from view in early fall, and is now arriving in the morning sky, with fleet-footed Mercury keeping it company.

These two planets are just barely visible this week in the glare of the Sun's early light, and are helpful markers in the quest to find Comet ISON. However, as ISON races toward its close encounter with the Sun on Thanksgiving day, it is pretty much out of sight, lost in the sunlight that bathes the eastern horizon.


15 November 2013

Leonid Meteor Shower 2013 + Comet ISON

Comet ISON in Virgo
The Leonids peak this weekend, a lovely annual shower that is the result of a periodic comet that has left a field of debris that is 'bumped into' by the Earth. Like all meteor showers, the Leonids are best viewed after midnight, and can appear almost anywhere in the sky. Like all meteor showers, the best view is under a dark sky away from city lights. Unfortunately we have a full Moon this year for the Leonids, and that means that even in dark conditions, the bright light of the Moon will wash out many of the meteors. So although this is not the best year for this particular shower, there is a bonus: if you get up early to see the meteor shower, you will also get a good look at Comet ISON, which is passing through the constellation Virgo on its way toward the November 28th rendezvous with the Sun.  A good bet is to get up early on Sunday November 17th and enjoy a view of Comet ISON as it passes near the bright star Spica, and watch for a few meteors in the process. Finder chart here, or just use the map on the right. I wish you clear skies and good viewing!

Image courtesy EarthSky.


06 November 2013

Comets are all around us!

November 2013 is becoming Comet Month, with Comet ISON on its way toward the Sun, and now Comet Lovejoy making a nice appearance in the morning sky as well.

Comet Lovejoy
Comet Lovejoy is well positioned in the eastern sky in the early morning hours this week, with the famous Beehive Cluster as your guidepost. This article on EarthSky has a lot of helpful information for finding the Beehive and therefore Comet Lovejoy this week. I'll take a look in the morning and report what I can see.

Astro Bob's blog has some good information about Lovejoy as well. Get out your binoculars!

27 October 2013

The Royal Sky


Every Fall, the royalty of the sky rises in the north-east and showcases a very fine part of the sky that includes the outer reaches of the band of the Milky Way, a galactic treasure, and a few easy-to-spot patterns that are easily visible in the night sky.

The Royal Sky
The trio includes Cepheus (the King), Cassiopeia (the Queen), and Andromeda (the Princess). In the early evenings this time of year, they are in a line from nearly due North toward due East, and the middle of these three constellations is quite bright and easy to locate in the sky. Over the course of the evening, they gradually shift position, spiraling out from the north circumpolar region of the sky toward the zenith, following closely the Great Square of Pegasus (of which Andromeda shares a corner star, Alpheratz).

I enjoy looking at this region through binoculars, with the outer reaches of the Milky Way visible in and around Cassiopeia, and of course the treasure of this part of the sky, the Andromeda Galaxy (M31).  Take some time to enjoy this royal corner of the night sky, brimming with discoveries small and large. 

Image courtesy of Sky Safari.

11 October 2013

Comet C/2012 S1 - Comet ISON Approaches

Comet C/2012 S1
Comets are beautiful and engaging to watch, gracefully floating across the night sky, arriving unexpected and sometimes surprising us with an extraordinary show. Some comets are regular visitors to Earth ("short period comets" such as Halley's Comet) and are very predictable, but others arrive from the vast reaches of the outer Solar System (the Oort Cloud) and make only one pass through our neighborhood, never to be seen again. Comet C/2012 S1, better known as Comet ISON, is of the latter category, packing enough ice and mass to become 'the comet of the century' when it has a rendezvous with the Sun in late November. Predictions of spectacular comets sometimes miss (anyone remember Comet Kohoutek?) so we always try to plan for comets with lowered expectations and hope to be pleasantly surprised.

Finding Comet ISON
Comet ISON passed near Mars a few weeks ago and is on a near-collision course with the Sun. A comet with a close encounter like this is called a Sungrazing Comet -- Comet ISON will pass within a solar diameter of the Sun, so close that it might not survive the trip back out of the Solar System. If it does, however, it is expected to have a beautiful tail and could be quite a spectacle. We have to watch and see.

This coming week provides an opportunity to spot Comet ISON as it appears in the morning sky, when it will be in close alignment with Mars and the bright star Regulus. Look to the east before sunrise (around 5:00 or 6:00 am) and use some kind of optical aid such as binoculars, and you'll have a nice view of the comet. I'll be out each morning to take a look, and will update the blog with news.

Images courtesy of NASA/Hubble, and EarthSky.org.

Update October 15: have tried two mornings in a row to spot ISON with binoculars from San Francisco, but have not yet found it. Either it is quite tiny, too faint, the skies here are too light polluted, or all of the above. Will continue to try the remainder of this week.

23 September 2013

Bright Stars and Planets in the Morning

Fantastic Morning Sky
I get up early, and I am quite aware of the fact that as autumn begins, the mornings are darker and darker. Here in the west side of San Francisco, autumn is when our clear skies return (following the summer fog) and the sky starts to come alive. My early start of the day means that I get to see the fabulous winter skies and the brilliant planet Jupiter when I step outside to get the newspaper. The southeasterly view just before dawn is riveting, with Jupiter dominating
the sky to the east, and the stunning constellation Orion, and the brightest star in the sky Sirius, to the south.

Later this week, the waning gibbous Moon glides high across the sky, passing near Jupiter on the 28th. As the sunrise moves a few minutes later each morning, the sky becomes more accessible and if you can spare a minute of your morning routine, you'll like what you see.

Image courtesy of Sky & Telescope.

06 September 2013

Venus and the Crescent Moon Pair Up

Moon and Venus pair up
Sunday September 8th will be a good day to go to the beach (or anywhere with a good western horizon) to see a great alignment of brilliant Venus and a young thin crescent Moon hovering above the horizon minutes after sunset. The two will be a beautiful pair for the hour after sunset (7:30 pm here in San Francisco) and as the sky darkens in the minutes after sunset, Earthshine on the Moon should be outstanding. The skies in the San Franisco Bay Area are at their best of the year, clear and calm. Can't wait to look at this!

EarthSky recommends that you use the Moon to help you find Venus during the daytime. Yes, you can see the brightest celestial objects in the middle of a sunny day if you know where to look. I think it's quite cool to spot the shiny dot of Venus hanging in the bright blue sky. It's a real challenge to find, but worth the search. Best of luck with that, and if you don't find Venus in the day, you'll certainly find it after sunset.

31 August 2013

A Sea of Deep Space Objects

The Galactic Center
The waning days of Summer are an excellent time to enjoy a view into the heart of the Milky Way Galaxy. We observe our own galaxy all around us in the night sky, and if you are in a reasonably dark location, you can see the band of stars that are the spiral arms of our own galaxy stretch across the sky. At this time of year, as the sky darkens after sunset, the Milky Way stretches high overhead, touching the southern horizon at the constellation Sagittarius. In fact, when you look due south toward that very constellation, you are looking toward the center of the galaxy. Not surprisingly, you also can see a lot of beautiful deep space objects, and with a pair of binoculars you can see many interesting objects, from clusters of stars to nebulae. The diagram gives you an idea of the richness of this part of the sky and galaxy, and even in city lights you will still be able to spot many of these objects. A telescope is fine to use as well, but I find that binoculars give you a big picture and are quite good for seeing the colors and breadth of many of the big nebulae in and around Sagittarius. 

Six months from now, as the Earth swings around the Sun and our view of the night sky has shifted, we'll be pointing the opposite direction toward the 'antipode' of the Milky Way Galaxy, a much less interesting part of the sky (but still cosmically significant). So enjoy Sagittarius and the center of the galaxy while you can.

22 August 2013

The SETI and Europa Report

I don't post movie reviews on my blog, but I will talk a bit about a very interesting science fiction movie I enjoyed recently. The movie is called Europa Report, and it is a fact-based sci-fi, something that I quite enjoy because it employs very solid science and technology in its depiction of the future. In this case, the story is of a search for extraterrestrial life, a trip to the Jovian moon Europa in hopes of finding the first sign of life outside of Earth.

Europa Report poster
I find the search for extraterrestrial life and SETI (extraterrestrial intelligence) to be an excellent scientific endeavor, and the latest discoveries of exoplanets on the Kepler Mission, and the ongoing search being conducted by the SETI Institute at the Allen Array in Northern California, along with advanced astrobiology research going on at SETI in Mountain View, all are part of the grand search that captivates so many -- the ongoing pursuit of an answer to the question "are we alone in the universe?" I am happy that we live in a world where some of our tax dollars and donations support these scientific endeavors

The movie Europa Report, like Contact and Deep Impact, are portrayals of unusual or theoretical situations that attempt to remain scientifically grounded. I once heard astronomer and blogger Phil Plait give a fairly in depth assessment of Deep Impact, and although it has some flaws, it is mostly on the mark and an exciting movie for the subject at hand, a comet impacting the Earth. Europa Report follows the story of six astronauts on the long journey to one of Jupiter's moons, Europa, because it contains a large ocean of water under a layer of ice, and could harbor life. Without spoiling the movie ending, I'll simply say that the drama and excitement (and danger) of this kind of journey are well captured in this movie, and if you want an entertaining and riveting evening out, go see the movie. If you'd like a proper movie review, here are some good ones: Space.com is good, as is Roger Ebert's review and the review on io9.

08 August 2013

KALW Broadcast - August 8, 2013

I provide a fairly in-depth outline of the Perseids and how to see them during this interview with Ben Trefny of KALW's Crosscurrents program. Click here to listen.

KFOG Broadcast - August 8, 2013

Today's discussion with Greg Gory and the Morning Show team at KFOG includes the Perseids, the International Space Station, Star Parties and Saturn. Listen here. 

06 August 2013

Perseid Meteor Shower 2013

It's August, and that means it's time for one of the best meteor showers of the year, the Perseids. This shower occurs every year around August 11-12-13, bringing with it the promise of 50-100 meteors per hour under ideal viewing conditions. There are a lot of great resources on the web to learn about it (see below). For San Francisco and Bay Area residents, here are my thoughts on how to best enjoy it.

In the City: San Francisco and the Bay Area have a bit too much light pollution to see all of the meteors clearly, but you will certainly see some within city limits. The most important things are (a) to have a broad horizon with a view of as much of the sky as possible, and (b) to situate yourself in as dark of a spot as you can find, ideally shaded from streetlights or houselights. Let your eyes adapt and look overhead; you could see 5-10 per hour.

Outside the City: The best way to enjoy a meteor shower is outside of city limits, where darkness prevails and you have a broad view of the sky. As with any stargazing endeavor, you want to dress warmly and bring along creature comforts such as a sleeping bag, lawn chair, and a warm drink. Give yourself plenty of time to dark-adapt. And do this with friends -- it's much more fun when you share this with others.

Where to look: Directly overhead. They appear to originate from a spot in the eastern sky in the constellation Perseus, but they will be visible over all of the night sky.

When to look: meteor showers are always best viewed after midnight, when the rate of meteors goes up considerably. The peak nights for the 2013 Perseids are Sunday night (11th-12th) and Monday night (12th-13th), although Saturday night August 10th will be a fine night as well, as the meteors start to approach their peak and the weekend is in full swing.

In you live in the Bay Area, join the San Francisco Amateur Astronomers high atop Mt. Tamalpais for a full evening of astronomy and meteor watching on Saturday 10th. We'll have a lecture, star gazing through telescopes, and meteor viewing until 1:00 am. Admission is free. More details here: http://www.sfaa-astronomy.org/

Here are two excellent web resources on the Perseids:

http://www.skyandtelescope.com/observing/home/Get_Ready-for-the-2013_Perseids-218037521.html

http://earthsky.org/astronomy-essentials/earthskys-meteor-shower-guide

Enjoy the show!

04 August 2013

A Graceful Moon

A Graceful Moon
This week we enjoy the start of the lunar cycle, from New Moon on the 6th through the waxing crescent phases. The Moon travels higher and more southerly each evening, as it starts its monthly orbit around the Earth, gracefully slipping along the ecliptic and closely brushing up against planets and bright stars. The view on Thursday 9th should be particularly engaging, as bright Venus stands in contrast to the brighter (but more diffuse) thin crescent Moon. You will need a good western horizon to enjoy this, where the pair will shimmer in the dusk sky. Later in the week the Moon will slide past bright star Spica and Saturn, and happily will set well before midnight, so as not to interfere with the Perseids meteor shower. More on the Perseids in my next blog post. For now, Clear Skies and Happy Viewing!

29 July 2013

Clear Skies!

Amateur astronomers often sign off an email or message with the phrase "Clear Skies" because anyone interested in enjoying the night sky needs to have a clear sky to start with. I often close blog posts on this blog with the phrase "Clear Skies!" as a kind of wishful thinking and good luck charm.

Right now in San Francisco, I need all the good luck I can get. The coastal weather pattern each summer ensures that clear skies will be rare indeed, especially in the Outer Richmond district where I live. So I have had precious few viewing opportunities from my own backyard this summer, and the San Francisco Amateur Astronomers have been forced to cancel most of their "City Star Parties" that take place near Lands End on the western side of the city, due to fog.

Venus and the sunset sky
When we get the rare clear sky, or when I am in another part of the Bay Area and am enjoying a stunning view of the western horizon just after sunset, I am reminded why I love astronomy; the beautiful changing color of the sunset sky, and the gradual transition into night, and the dazzling light of Venus in the west, all combine to motivate me to look up in the sky, and more than ever, I appreciate the clear skies that usually are available here in the Bay Area.

So to all of you, I wish you "Clear Skies" and a warm night somewhere this summer to enjoy the heavens.

Image courtesy Pete Lawrence.

16 July 2013

The Five Visible Planets

As an amateur astronomer and public speaker, I find the five visible planets fascinating. These 'wanderers
The Solar System
' are beautiful to watch with the naked eye, and are interesting in a telescope as well, even in a big city. Consequently, I am a close watcher of the changing motions and of these bodies, and I point them out often to groups at star parties. The planets all follow the band of the Zodiac across the sky, of course, because they move along the ecliptic, the projection of the orbits of all of the Solar System planets across the sky. And as such, their motion is interesting to watch, whether they are the inner planets of Venus and Mercury with their unusual twilight appearances, or the outer planets of Mars and Jupiter and Saturn, enjoying long seasons in the limelight of the night sky. 

We just had some interesting patterns of planets and stars, and of course can always enjoy those by knowing where to look for the five visible planets. Earth Sky has a fine article on these planets for July.

21 June 2013

Solstice and Super Moon: Transitions

We have two special moments this week in the heavens, moments that attract public attention because they are transition points in the cycles of nature. As Earth orbits the Sun, and the Moon orbits the Earth, we are aware of changes in the relationship between these bodies, and the special alignments that come and go. This week, we experience the Summer Solstice in the northern hemisphere, and also a Super Moon, a full moon that coincides with the closest approach of the Moon to Earth.

Solstice is a special moment, driven by the Earth's tilt with respect to its orbit around the Sun. The 23 degree tilt of Earth's axis brings about considerable change in the length of time the Sun is above the horizon, and obviously that affects weather, and affects how people live, in particular in northern latitudes. Solstice marks the seasonal shift from lengthening days to shortening days. June 21st marks the moment this year when that happens.

Super Moons are a popular thing now, and this too marks a special moment, a transition in the Moon's orbit around the Earth when the Moon reaches the closest point on its elliptical path, and appears larger in the sky. Along with the somewhat larger size in the sky comes an increased impact on tides, and groups such as the California King Tides Initiative have worked to raise awareness of global warming by measuring the impact of high tides on coastal communities. This month's Super Moon occurs on the night of Saturday June 22nd to the morning of Sunday June 23nd, when the Moon reaches perigee (closest approach to Earth) within a few minutes of the moment of Full Moon.

The heavens are full of moving objects, from the planets in the Solar System, to asteroids and comets, and even galaxies and stars. All of this motion creates patterns and alignments that are beautiful to behold. And the transitions between key alignments make for interesting moments to ponder our place in the universe.

15 June 2013

Hercules

The Stars of Hercules
The early summer skies feature a fascinating constellation that climbs high into the night sky and provides several interesting features to see with the naked eye, binoculars or a telescope. Hercules is the Roman mythological hero that is adapted from the Greek hero Heracles. In the night sky, he is kneeling in the sky with a club overhead, engaged in battle with other mythological enemies throughout the heavens. Similar to Orion the Hunter, Hercules has a distinctive shape; in stark contrast to Orion, Hercules has no bright stars - no first magnitude stars, and only one that is barely second magnitude, and hence Hercules takes some effort to find. But it's worth the effort.

Hercules is visible due east after sunset in June, and is directly overhead by midnight. The middle four stars form a distinctive shape, well known to astronomers as the Keystone. This trapezoidal shape is the center of the figure of Hercules, and it contains a beautiful deep space object known as Messier 13, the Great Globular Cluster in Hercules. It is a spectacular sight to behold in binoculars or a telescope; M13 is a rich cluster that shimmers from the 300,000 stars located in it.

The stars of Hercules are not particularly bright, but they are quite interesting. One of the brightest stars is called Rasalgethi, and it is a a binary star system with a red giant star and a companion that orbit each other every 3,600 years. The brightest star is called Kornephoros, a yellow giant star 148 light years from Earth.

Exploring the heavens is more fun when you know what to look for. Spend a few minutes on Hercules with a telescope or binoculars, and you'll see plenty of interesting objects, even from within a big city.

Image courtesy of SkySafari.

02 June 2013

Transitions in the Evening Twilight

Every night, the sky appears a bit different to us, and in June as the long days of summer unfold, the sunset sky changes more rapidly than usual. The trio of planets that dominated dusk are now a pair, as Mercury and Venus climb higher into the west, and the bright stars and constellations of winter rapidly fade from view.

June's evening sky
The bright twin stars Castor and Pollux in the constellation Gemini are dropping gradually into the western sky after sunset, and the later and later onset of darkness combine with the change in position to speed these two stars out of view over the coming days. As they are lower and lower each night, Venus and Mercury will move higher each night and over the next 3 weeks, they will move closer to each other.

As you watch the changing landscape in June, take note of the gradual slowing in the onset of darkness as we approach the summer solstice later this month. The evening sky is a beautiful place to see transitions, and the visiting planets this month provide a fine guideline for this.

22 May 2013

The Dance of the Planets - a spectacular celestial alignment

This week is the culmination of a spectacular celestial alignment, creating a rare and beautiful triangle of three planets on Sunday 26th. The planets will be low in the west after sunset, and as the glare of the sunset fades, the three bright dots of light will emerge from that glare, and if you have a good western view, you'll see them for a short window of time before they set.

The Triangle of Planets
Jupiter has been dominating the night sky for months, but each successive night has brought it closer to the time when it slips 'behind' the Sun, from our vantage point, and is shielded from our view. This happens to all of the outer planets throughout the course of a year or two. But by cosmic coincidence, Mercury and Venus are rapidly rising into the sunset sky, as their orbits bring them out of the glare from being 'behind' the Sun, and they quickly pop up into the evening sky. This week, they appear to move higher and higher in the sky just as Jupiter is 'falling' and they cross over in a lovely pattern.

To see this spectacle, head out any evening and look west. The configuration will be changing noticeably each night, and for me, that is the real fun here -- to not only see a rare and unusual alignment on Sunday, but to watch the set up in the days before and after. Here are a number of good links with additional information:

Sky & Telescope Magazine
The Always-Engaging Tony Flanders on SkyWeek
NASA Science Cast

Enjoy the show, and may you have clear skies!

Image courtesy of Sky & Telescope

10 May 2013

Planetary Trio 'Warm Up Act'

During the month of May, three planets are going to move into a very close alignment, and the set up begins this week with the Moon adding some color to the scene for a few days. The two fast-moving inner planets, Mercury and Venus, are going to be coming into view in the west shortly after sunset, joining the massive Jupiter as it slowly fades out of view into the twilight. The dynamics of these changes is not easy to explain in a short blog post, but because of the fact that inner and outer planets appear to move differently from our Earth-bound perspective, the planets will all appear to 'cross over' in the west over the next few weeks, and the view should be dramatic.

The Moon adds color to the view.
This weekend, the show starts with Venus emerging from the glare of sunset into the western sky. You'll need a low western horizon to see this, in particular with the young Moon on the 10th. The alignment of Jupiter, the Moon and Venus on the 11th should be nice, and then as the Moon rapidly moves out of the scene, look for Venus (and shortly thereafter Mercury) to move up higher and higher in the twilight sky, leading to a much more spectacular lineup. More on that in my next blog post.

Image courtesy of Sky & Telescope.

30 April 2013

SkyWeek video - an excellent online astronomy resource

There are many astronomy resources on the web that help you to better understand the night sky. One of the finest is the 5 minute video from Sky & Telescope Magazine entitled SkyWeek. Hosted by associate editor Tony Flanders, I find these weekly videos to be quite illuminating, combining the highlights of the night sky with science and understanding of the things you are seeing. Tony delivers all of this with a great sense of wonder and enthusiasm, without talking down to the audience. I always feel like I am being taught something new and interesting, combining simple observations with deeper astrophysics.

I had the pleasure of spending time with Tony and his family while on an eclipse expedition several years ago, and I really liked how he could balance the far ends of the spectrum of observational astronomy and astrophysics. He has been creating SkyWeek episodes for about one and a half years, and I hope he continues for a long time into the future. The show is carried on many PBS affiliates, adding considerable depth to the quality educational lineup available on public television.

Click here to view.

27 April 2013

Saturn at Opposition 2013

Typical Telescope View of Saturn
Saturn reaches a special moment in the sky for us Earth-bound viewers, a time when conditions are most favorable for viewing the 2nd largest planet in the Solar System in all its glory. Opposition is the time when the planet is directly opposite the Sun, from our Earthly point of view. That means a few things: (a) it is at its closest to Earth, and therefore brightest for the year, (b) it is visible all night, rising just after sunset and setting just before sunrise, and (c) it is illuminated straight overhead from the Sun, much in the way we view a full moon.

For the city dweller, Saturn is an easy object to find, outshining most of the stars in the sky except nearby Arcturus, and its rival planet Jupiter (which is slowly fading into the west earlier each night). Saturn glows a yellow-white hue, in contrast to another nearby bright star, Spica. To find Saturn, it rises right after sunset this evening and for the foreseeable future, and glides from the south-east to the southern sky, and then across to the south-west after midnight.

If you have a telescope, now is the time to put it to work, as the view of Saturn will be at its finest. Wait a little while after sunset until Saturn is higher in the sky, less susceptible to atmospheric effects. The ring system is tilted 18 degrees toward Earth, so the view is quite good, and as anyone who has seen Saturn in a telescope will attest, the rings are amazing to see with your own eyes.

Here are two good resources for learning more about Saturn at opposition: Sky and Telescope's fine article, and EarthSky's tips how to find Saturn using the Big Dipper, Arcturus and Spica.

Image courtesy Wikimedia Commons

18 April 2013

Moon Musings

Lunar Terminator
As the Moon reaches first quarter phase, I find myself drawn to the Moon's 'terminator', the line that separates dark from light. At first quarter phase (happening this week), the Moon presents Earth a very fine view of the terminator, exposing the highs and lows of the surface of the Moon. As I regularly point out to people during star parties, the region of the terminator during the waxing phase of the Moon is the region of sunrise, the place on the Moon where the Sun is just emerging above the horizon for what will eventually be a long lunar day (this takes 29 'Earth-days' to complete). As such, the illumination on the Moon's surface is much like you would expect on Earth at sunrise: long shadows across the land, with unusual features such as valleys and mountains being partially illuminated. The image attached (courtesy of APOD) shows the view through a telescope of the terminator, with shadows clearly visible in the craters and from the peaks of the mountains.

Tonight will be a fine time to peer at the Moon with anything you have at your disposal. It's the easiest target to find with a telescope or binoculars, and it's always visible even in the worst city lights. And it's a treat to see something unusual yet familiar, the sight of sunrise on another world.

09 April 2013

Get Involved: Star Parties at Mt. Tam

Mountain Theater Lecture
It's spring, and that means it's time for star parties at the Mountain Theater on Mt. Tamalpais in Marin County. Always a favorite place for stargazing, I am looking forward to being a part of the magical Saturday nights with lectures, star gazing and amateur astronomer telescopes each month.

The Friends of Mt. Tam (formerly the Mt. Tam Interpretive Association) have been sponsoring astronomy nights on Mt. Tam for 25 years, and this year will be another excellent one with monthly lectures from professional astronomers on topics such as Dark Energy, Asteroids, Mars Exploration and Climate Change. Following each lecture, I give a short tour of the night sky, and the San Francisco Amateur Astronomers host a star party with powerful telescopes to peer into the dark sky visible high above the fog on Mt. Tam.

The nights on Mt. Tam are a terrific astronomy experience and the price is free, so there's no excuse for not taking part. Families are welcome, and guests bring food and drink as well as cushions and warm blankets to really enjoy the evening there. The first event kicks off this Saturday April 13th at 8:30 pm, featuring Dr. Robert A. Rhode of the Berkeley Earth Surface Temperature. His lecture is entitled “Understanding the Climate Change of the Last 250 Years”. Click here for details.

I hope to see you Above the Fog on Mt. Tam sometime this season.

Image courtesy of Weekend Sherpa.

23 March 2013

Seeing Earth's Shadow and the Belt of Venus

Earth's Shadow and the Belt of Venus
While waiting for the sky to darken, especially when I am at a star party, I like to point out the many subtle changes in the night sky that unfold from the moment of sunset to the end of dusk. One of my favorites is the phenomenon known as the Belt of Venus, a beautiful pink and blue band that stretches along the horizon exactly opposite the point of sunset or sunrise.

Most of the time I see this phenomenon in the evening, since that is when I am most often focused on the sky while it transitions from light to dark and the star gazing begins. Of course, the reverse effect is plainly visible in the morning just before sunrise, and all of the elements of the effect move in reverse. Recently I had an unusual experience with the morning version of this phenomenon, and it was accented by the Moon.

In January, while driving to work early in the morning, I was particularly captivated by the setting Full Moon. The previous night was the exact time of the Full Moon, so as I left home shortly before sunrise, the bright Moon was just setting to my right in the clear western sky as drove south along the Great Highway in San Francisco, directly on the coast. During the 8 or 10 minutes I was driving along the coast, the Moon was quickly dropping low on the western horizon, minutes away from setting. I could clearly see the Belt of Venus emerge, as the dark shadow of Earth became more and more distinct low on the horizon. The specific thing that fascinated me was that the Moon itself, as it set, appeared to be “pulling” the band of darkness with it. The lower the Moon, the lower the dark shadow band on the horizon. This image from Jeff Sullivan captures the situation perfectly.

The technical underpinning for this sight was that a Full Moon is precisely opposite the Sun, and the Full Moon, a few hours after the exact moment of fullness, appears directly in the dark shadow band of the Earth and not above it – otherwise it would not be a Full Moon. And if this happened during an Eclipse Season, the Moon would be encapsulated by the distant shadow of the Earth and would itself be darkened, along with the atmosphere around its position in the sky. The morning I observed this in January was not at a time of eclipse, but nonetheless the Moon was decidedly well placed in the shadow band of Earth, and as it slipped below the horizon, the dark shadow set, and the pink belt faded, and minutes later the Sun peeked up above the horizon. What a lovely view that was, indeed, appearing as if the Moon was pulling the dark band with it, but in fact, the Moon was simply in lock step with the shadow, inseparable at that particular point in its ever-so-slightly-post full phase.

The subtle changes in the dusk and dawn sky are marvelous, but this phenomenon, the Belt of Venus, is particularly subtle because most people like to see the sunset or sunrise, and rarely turn around to look at the other horizon. Next time you get a chance, look, and you’ll be pleasantly surprised, particularly if you witness it at a Full Moon with a crystal clear horizon.

Here are two excellent articles about the Belt of Venus by astronomers I respect:
Tony Flanders of Sky & Telescope.
Phil Plait of Bad Astronomy on Slate

Image courtesy Wikimedia Commons.

12 March 2013

KALW Broadcast: Asteroids, Comets and PanSTARRS

I paid a visit to KALW, San Francisco Public Radio, and talked with Ben Trefny about asteroids, comets and of course, PanSTARRS on their evening program Crosscurrents. Listen in to our lively discussion about the beauty and dangers of things roaring by from outer space! Click here to listen.

03 March 2013

A Comet in the West: PanSTARRS from San Francisco

Comet Panstarrs in March
We have a comet about to emerge into the evening sky. PanSTARRS will be a nice sight, not a magnificent comet but an easy target that will be visible in the dusk sky in the next 2-3 weeks. I plan to look for it from Ocean Beach here in San Francisco, where the clear ocean horizon should provide a good setting.

Comet PanSTARRS is currently visible from the Southern Hemisphere, but will move north and into view later this week. Although its low apparition will not make it shine very brightly, it will be a lovely sight for those who make the effort to view it, especially through binoculars, where the image is best seen. A telescope will zoom in too far, and naked eye viewing of PanSTARRS will probably be unimpressive, so I strongly recommend a pair of binoculars to see the comet at its best.

Sky & Telescope Magazine has a very good updated page on the latest on the comet. And more information is also available on the Earth Sky website.

Image courtesy of Sky & Telescope.

Update March 12, 2013: Saw PanSTARRS from high above the Bay Area, on Skyline Boulevard near highway 92. I needed binoculars to see it well, making a beautiful appearance next to the young crescent Moon. It's work to find, but worth it.

22 February 2013

KGO Broadcast - February 16, 2013

Last Saturday I had a fun experience: joining KGO 810 Talk Radio in San Francisco for a one-hour broadcast. Greg Gory invited me to stop by and talk about asteroids, meteors, fireballs and many other astronomy topics, and we had a fine time doing all of that and more! We entertained calls from listeners and ended the show on a high note, discussing why we go into space and explore in the first place. Click here to listen.

16 February 2013

A Perfect Time to see Mercury

Mercury in February
Mercury is the most elusive of the visible planets in the Solar System, never drifting far from the glare of the Sun, and always on the move. So you should take advantage of the upcoming weeks when Mercury will be well positioned in the sunset sky. Mercury is a small planet so it will not have the bold bright shine of Venus or Jupiter, but it will certainly stand out as a bright speck of light in the dusk sky. Look soon after sunset for a point of light that becomes increasingly bright as darkness sets in. You'll need a good, clear western horizon to see this. But take a minute some evening and spot it, since it won't be this easy again for a while.

Image courtesy Sky & Telescope.

13 February 2013

Asteroid Alert! 2012 DA14 swings by Earth

This Friday, a small asteroid will pass quite close to Earth. 2012 DA14 is a 60 meter ('Olympic pool size') asteroid that will pass between the low-Earth orbit satellites and geostationary satellites, at a distance of about 17,000 miles, a close shave by astronomical terms, but not something that is posing any kind of threat to the planet.

Asteroids pass near to Earth all the time, and the largest of them are being closely tracked. At this time over 1300 potentially hazardous asteroids (PHAs) are being watched, but none of them are on a collision course with Earth. For the foreseeable future, we have nothing to worry about - - at least as far as asteroids go!

If you want to watch the fly-by, you can check out a number of websites that will have live video feeds of the asteroid. At closest approach, it will be daytime in California and not visible, but the video feeds will be delivered from the other side of the planet. It won't be overly dramatic -- just a spec of light moving against the backdrop of stars. As one website put it, the size and distance of 2012 DA14 will be, on the scale of a 12-inch globe of the Earth, a grain of sand 2 feet away from the surface of the Earth. That's a good reference.

07 February 2013

Get Involved: Star Parties/Learn to Use a Telescope

Every month there are numerous opportunities to get involved with the fun and science of astronomy. The NASA Night Sky Network is a good place to start if you want to find a local event, and in this post I'll provide some local suggestions if you live in the San Francisco Bay Area.

Star Party
I love presenting the sky at star parties and giving talks about astronomy, so I signed up to do this for the Marin County "One Book One Marin" celebration happening this year. Check the calendar for dates, and join me at different libraries in Marin for an introductory lecture on the Solar System and constellations, and star gazing (if weather permits). The first two events are on February 11th and 12th. The San Francisco Amateur Astronomers will also host star parties on different nights in February and March.

The San Francisco Amateur Astronomers (SFAA) club has an open monthly meeting, where anyone may attend to hear very topical lectures on a variety of subjects related to astronomy and space research. The upcoming lecture and calendar are found on the website. And on Saturday February 16th the SFAA is hosting a Star Party and New Scope Forum where you can dust off and bring out your old telescope for a primer on how to use it, and then a chance to put it to work looking into the heavens.

The Peninsula Astronomical Society and the always-excellent Dr. Andrew Fraknoi put on star parties and outstanding lectures in Los Altos Hills. And the wonderful Chabot Space & Science Center has very fine telescope nights featuring their giant telescopes on Friday and Saturday nights year-round.

Get involved! You won't be sorry.

03 February 2013

Planetary Conjunction at Dusk: Mars and Mercury

Mars & Mercury
This week, you will have a chance to spot elusive Mercury in the dusk sky, as the fast-moving planet gradually slides into the evening sky for a February showcase. In the first few days of Mercury's evening apparition, it moves past Mars, which itself is fading into the evening twilight. To spot these two planets in conjunction (close encounter) on February 7th and 8th, you will need binoculars or a telescope, and a clear western horizon. The two will form a very close pair for a couple days, and then Mars will continue its fade into the glare of sunset while Mercury will race eastward, appearing higher in the sky for the middle of the month. It will be work to find these two, but a fun challenge if you have clear western skies.

The image shows the view 30 minutes after sunset. The Sun sets in San Francisco around 5:40 pm this week.

Here's a helpful short video clip from Sky & Telescope's Tony Flanders showing how to find the two planets in conjunction, and how to find Mercury during the month of February.

Image courtesy of Sky & Telescope.

27 January 2013

Seeing the International Space Station

International Space Station
The International Space Station, or ISS, is a wonderful sight to see. It is Earth's 2nd largest satellite (after the Moon, of course). The ISS shines brightly because of the reflective surfaces across its trusses that shine brightly in the sunlight, and make the ISS look like a bright planet that moves relatively quickly across the sky.

The ISS only appears in the sky for a short while after sunset, or before sunrise. It is in orbit about 225 miles above the surface of the Earth; for example, shortly after a sunset the ISS catches sunlight and shines as it travels across the sky. When you get a very good alignment and it passes nearly overhead, it can reach the same magnitude as a bright Venus, and therefore be easy to spot. On such a pass, it takes about 5 minutes to travel from horizon to horizon, covering over 1000 miles in that time.

ISS visibility depends upon your location on Earth, since the best times to see the ISS in one part of the globe won't be the same as another. NASA has an an excellent web resource for this; for ISS sightings in San Francisco, we have morning passes right now, and will soon have good visibility in the evenings starting on February 5th. The iPhone app ISS Visibility is quite helpful for locating the ISS, with maps and easy-to-follow directions.

Best of luck seeing this wonderful sight. Image courtesy of NASA.

17 January 2013

Astronomy Events in 2013

Every year is full of special moments in the sky as planets and stars and the Moon align to create noteworthy patterns and special views. 2013 will be marked by many special moments, so here's a quick overview of them.

Comets

Comet Hale-Bopp
The event of the year could be the fly-by of Comet Ison, currently en route for a November 28th close encounter with the Sun, potentially lighting up the night (and even daytime) sky. More information on Comet Ison here.

Asteroids

Mark your calendar for February 15-16, when Asteroid DA14 will pass within 10,000-20,000 miles of the surface of the Earth. This is a big asteroid, at 125 feet, and could cause considerable damage if it was to impact. Lucky for us, we will not have anything to worry about. More here from Earth Sky.

Eclipses

Only one eclipse will be of significance for the West Coast, on October 18th when the Moon will pass within the Earth's penumbral shadow. This partial eclipse will start before moonrise in California, but once the Moon rises, should be a nice sight.

Occultations

Every month as the Moon slips past planets and stars in the night sky, there are moments when a distant object is blocked out by the Moon, called an Occultation. This year there are several close encounters that should be quite fun to watch from the Bay Area. Depending where you are on Earth, you can see more or less of these events. A few noteworthy ones: January 21 and March 17 when the Moon passes very close to Jupiter; and February 28-March 1 and July 15-16 when the Moon passes very close to the bright star Spica.

Be sure to check out the Year In Space calendar for 2013 which has fascinating facts and is a wealth of astronomy information for every day and month of the year. And happy viewing this year!

Image courtesy Wikimedia Commons.

07 January 2013

Alignments in the City Sky

Jupiter, Orion, and Sirius
I am viewing the sky this evening from one of the most densely populated urban areas, Manhattan. Looking up at the night sky here, you can't see many faint stars, but you can still see plenty of the brighter ones. Tonight looking toward the south, I was easily able to spot the fantastic alignment of Orion's belt, pointing downward toward the brightest star in the sky, Sirius, and pointing upward to the brightest planet in the sky in the evening, Jupiter. As Jupiter gradually moves in its orbit around the Sun, it will soon move out of alignment with Sirius, Orion's belt, and the bright star Aldeberan in the constellation Taurus. By the middle of 2013, Jupiter will be well on its way to the next sign in the Zodiac, Gemini. But for the coming weeks, you can enjoy the bright celestial alignment that can been seen from just about any location on Earth, even in the middle of an urban jungle such as NYC.

Image courtesy of Sky Safari.

02 January 2013

Quadrantid Meteor Shower 2013

The Quadrantids peak this evening and continue through Thursday January 4th, lighting up the sky with 'shooting stars' that are enchanting to see, if you have dark clear skies and are able to brave the wintery cold night. The Quadrantids ring in each new year with a good display of meteors, and are favorable for us in the Northern Hemisphere because the 'radiant' (the point from which the meteors appear to emanate) is high in the northern sky. Here are some helpful articles with more details about the shower.

EarthSky.com has a thorough article.

Space.com has helpful sky maps.

To enjoy the Quadrantids, follow the usual rules for a meteor shower: (a) dress warmly and have blankets or a sleeping bag, (b) avoid direct lights such as house lights, yard lights and street lights, (c) give yourself time to adapt to the darkness so your eyes can pick up faint meteors as well as big bright ones, and (d) give yourself a view directly overhead with as few obstructions as possible. If you get lucky, you can see up to 40 meteors per hour.