Viewing all 5 Visible Planets in one night

As the nights grow longer and the skies darker, we have the chance for the next few weeks to see all five planets visible to the naked eye in a single night. Of course, there are seven planets in our Solar System (not including Earth), but two (Uranus and Neptune) are just too faint to see without optical aid. However, the rest (Mercury, Venus, Mars, Jupiter and Saturn) are spread around the entire sky, adding a lot of brightness to our already-shiny Autumn and Winter skies. This article in the science blog EarthSky is an excellent guide to help you find each planet. Of course, to find Jupiter and Venus you need little guidance because they are so bright, but Mercury, Saturn and Mars will be easier to find with some assistance from a sky map.

And if you are ready to look deeper and see all 7 in one night, here is a chart to guide you to Uranus and Neptune. They are both just west of Jupiter, in the constellations Pisces and Aquarius.

Image courtesy NASA.

Jupiter at Opposition -- closest approach for 2011

The Autumn evening sky is being dominated by one bright, shiny object: the planet Jupiter, which will be a highlight for several months in our skies. On October 28th, Jupiter reaches "opposition" in which it is in a line with the Earth and Sun (and no, that is not what has been causing the recent earthquakes in the San Francisco Bay Area!).

Image Courtesy NASA

When Earth travels around in its orbit, approximately every 13 months we have a close encounter with Jupiter. When we do, the gas giant looks impressive with or without a telescope. Without a telescope, Jupiter is extremely bright, easily 50 times brighter than the brightest stars in the sky right now. It rises due East just after sunset, and remains visible the entire night. Through a small amateur telescope, Jupiter is a fine target, easy to locate and impressive with bands across its disk and the four Galilean moons shining brightly. Now is the time to get out a telescope or binoculars and share the brilliance of Jupiter with someone.

KFOG Broadcast - October 25, 2011

I was a guest on a live broadcast with the KFOG Morning Show today, talking about Jupiter, things to see in the Autumn night sky, the Pleiades, meteor showers, and the Bay Area Science Festival. The DJs on the Morning Show are an interesting group, and the conversation is always lively. Click here to listen.

Brilliant Moon and Jupiter

The Full Moon dominates the night sky this week, lighting the Autumn landscape and making its presence known as the soft grey glow of moonlight washes out all but the brightest stars in the sky. But even as the stars take a back seat in the night sky, the giant planet Jupiter shines steadily next to the Moon, undiminished by the intense glow of our nearest celestial neighbor.

Jupiter is nearing "opposition" in which it is at its closest approach to Earth for 2011. That means that it is also at its brightest, outshining all other celestial bodies in the night sky right now, except the Moon. For the next few nights as the Hunter's Moon passes near Jupiter, your attention will be drawn to the dazzling brightness of the largest planet in the Solar System. And once the Moon has moved into Last Quarter phase next week, Jupiter will remain steadfast in the evening sky, waiting for you to find it in binoculars or a small telescope. Take a moment and look up close if you have not seen Jupiter up-close. It's a worthy (and easy) target.

Image courtesy of Sky & Telescope Magazine.

Get Involved: Star Parties and Astronomy Lectures

There are many ways to get involved with astronomy. No matter where you live, you can find local clubs and events using the Night Sky Network website. Just about anywhere you go, you'll find a friendly astronomy club ready to welcome a new guest or member.

In the San Francisco Bay Area, we have a wealth of resources. As a member of the San Francisco Amateur Astronomers (SFAA), I always recommend the monthly lectures at the Randall Museum in the City, open at no charge to the public (next lecture on October 19th). The California Academy of Sciences has an excellent lecture series, the Benjamin Dean Lecture Series, focused on astronomy topics (next lecture on October 17th). And in the greater bay area, you'll find things happening at The Lawrence Hall of Science in Berkeley, the Chabot Space and Science Center in Oakland, Foothill College (lead by award-winning Professor Andrew Fraknoi) in Los Altos Hills, and more.

I take part in a few specific events. One of my favorite places to show off the night sky is at the weekly NightLife event at the Cal Academy in Golden Gate Park, every Thursday night. When the skies are clear, I can be found on the Living Roof showing off the skies with a trusty laser pointer, alongside Academy staff with telescopes pointing at the Moon, Jupiter, or other objects of interest. It is an excellent place to have fun and learn some new things about the night sky.

On November 5th, I'll be working with Tucker Hiatt of Wonderfest during the Bay Area Science Festival with a star party on Mt. Tamalpais in Marin County. We're calling the event "Nekkid-Eye Nightscape," and it will follow a lecture called The Milky Way as Dark Matter Laboratory. Tucker and I will give an introduction to the night sky, showcasing the best and the brightest objects in the Autumn Sky. After the lectures, the SFAA will be there with wonderful telescopes to show off the night sky up-close and personal.

I hope to see you at an event sometime soon!

One Year on Neptune

We passed a landmark moment this month, the one-year anniversary of the discovery of the Blue Planet, Neptune -- one Neptunian-year, that is, which is 165 of our Earth-years. This gem of a planet is something that an urban astronomer has to work a bit harder to see, but once spotted it is a lovely blue point of light in the sky, a fine payoff for those with the persistence to track it down against the backdrop of stars in the heavens.

During its long trek around the Solar System, Neptune has periodic close encounters with other planets, as it did during the "Triple Conjunction of 2009" with Jupiter. However, this year it stands alone in the constellation Aquarius, more challenging to find because we don't get Jupiter as a beacon leading us to find the elusive blue planet. However, using this star chart, a pair of binoculars, a dark backyard location, and some patience, I am sure you can find it. I will be looking from time to time over the coming months as Neptune moves from the morning sky into the evening sky, scanning for its dim blue glow in the vastness of the night sky.

Planetary Lineup on May 21st

With all of the talk about May 21st, I felt it would be helpful to guide observers to a genuine, heavenly lineup that will create a beautiful pattern in the morning sky on the 21st and 22nd. During the entire month of May, the four nearest planets to Earth have been creating a beautiful sight in the morning sky just ahead of sunrise. On May 21st and 22nd, Mars, Mercury and Venus form a compact cluster. Bright Venus is the "guide star" to help you find this grouping in the east. You will want to look about 30-45 minutes before sunrise, and you will need binoculars to see Mercury and Mars, but Venus will shine brightly despite the glare of the soon-to-be-rising Sun. Jupiter is also quite visible in the sky, but each day pulls away to the upper right (toward the south-east) a bit more from the other three planets. Note that the image of the view toward the east, which comes courtesy of Sky & Telescope Magazine, demonstrates that astronomers are confident we'll have something to see the morning of the 22nd!

Venus, Jupiter, Mars and Mercury in Conjunction

Four of the five most-visible planets are bunched together in the morning sky, creating beautiful patterns along the eastern horizon at dawn for the next few weeks. Each day the four planets change slightly in position, with bright Venus guiding your eyes to the right spot on the horizon where you can see these four points of light. Use binoculars to find all four planets - Mercury and Mars are much fainter than Jupiter and Venus - and use this amazing animation on the Sky & Telescope website to find the exact pattern as it changes each day. In San Francisco, you will want to look for this between 5:00 and 5:30 am, before the glare of the sunrise washes out the view of the planets.

Five Weeks of Planets in Conjunction

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

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

Jupiter and Mercury: Prograde and Retrograde Motion

Elusive Mercury makes an appearance for the coming weeks in the evening sky, slowly progressing toward Jupiter as the two planets share the same space (from our point of view) just above the setting Sun. Although Jupiter is considerably farther away from Earth as Mercury, Jupiter's massive size more than makes up for that distance and makes it appear to us as a much brighter light on the horizon.

As Mercury rapidly arrives in the evening sky, it changes its location each evening quite a bit, and before long will be aligned with Jupiter, setting around the same time as Jupiter toward the end of March. As it reaches this point, it will then change its daily direction across the evening sky and move rapidly westward toward the Sun, something called "retrograde" motion. For a few weeks, people will say that "Mercury is in Retrograde" which is, from an astronomical point of view, very normal behavior for Mercury every few months. However, for many who follow astrology, this can be a very troubling time. Perhaps seeing Mercury with your own eyes changing location and moving gracefully across the sky, first in prograde motion (the basic motion of planets across the backdrop of stars, eastward), then in retrograde, will make its impact a little more friendly. Try it out for yourself and see.

Jupiter's closest approach to Earth

Today Jupiter is at its closest point to Earth for 2010, a mere 368 million miles. Although not a particularly astonishing event, it is nonetheless a prime time to get out your binoculars or telescope to view the giant planet as it dominates the night sky. Jupiter is a fun target to view up close because it offers so much to see: Four bright Moons, colors and textures from its cloud belts, and for a brief time right now it guides you to find the distant planet Uranus.

Every year as the Earth moves around the Sun, at some point in time it is at its closest approach to Jupiter. This moment is called "opposition" and is when the Earth, Sun and Jupiter are all in a perfect line. Each year the distance between the Earth and Jupiter might be a bit more or less depending upon the circumstances of each planet's orbit. This year, the distance is smaller than usual (closest since 1963 and until 2022), but that difference is relatively small from year to year. More important is that the planet is at its brightest for the year, and remains high in the sky for optimum viewing for the entire night.

Sky and Telescope Magazine has an excellent article about this close encounter if you want more details.

Perspective of the Solar System

After weeks of foggy skies in San Francisco, the sky has started clearing, yielding spectacular sunsets and sky shows at Ocean Beach. I have been writing about (but not seeing much of) the amazing sight of the planets dancing across the evening sky. With the clear skies, the view was great, showcasing Venus and Mars very close together, with Saturn just to the lower right and the bright Zodiac start Spica (in Virgo) just to the upper left.

This configuration traces a curve in the sky and if you have a clear southern horizon you can "connect the dots" from this cluster of stars and planets to the south where bright Jupiter dominates the sky. Beyond that, the Moon is slicing across the lower southern sky, providing the observer with a nice visual of the Ecliptic, the line of the planets, Moon and Sun. This is a great way to visualize the path of the planets in the Solar System when you look out from our Earth-bound perspective.

Over the coming months, Mars and Saturn and eventually Venus fade, but the giant planet Jupiter will be dominating the Fall skies.

Old Moon, Young Moon

Every 29 1/2 days the Moon completes one cycle in its orbit around the Earth. For the last few days of the cycle we have an "old moon" and then just after New Moon we have the opportunity to see a very "young moon." I love the challenge of locating the very thin crescent Moon on the horizon, but when found, the reward is worth it, because the Moon always looks a jewel in the sky.

This week we've had a few opportunities to see the very old moon passing by Mercury in the dawn glare. After the New Moon on Saturday, find a good western horizon and try to locate the very young Moon in the glow of dusk. On Sunday 14th it will pass just next to Jupiter and Venus, extremely low on the horizon. You will want to have binoculars nearby to enhance the view. On Monday the Moon is higher in the west, and by Tuesday it is an easy target in the sunset sky. Well below the Moon on Tuesday, however, Jupiter and Venus have their closest approach for quite a while, being about 1/ 2 degree apart (a moon width). For this, you will want binoculars because the two planets will be just on the horizon after sunset.

Jupiter and a Young Moon

Despite the cloudy weather here in San Francisco these last few days, bright Jupiter shines through from time to time as it slowly works its way down the western sky after sunset. The next few days offer a chance to see one of my favorite views, that of the young Moon and a bright planet. In this case the waxing crescent Moon slides across the south-western horizon each night for the next few nights. With Earthshine illuminating the dark portions of the Moon, the visual effect is quite striking. If clouds part in the next few days, find a good western horizon for this beautiful scene.

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!

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.

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.

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!

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.