Rare comet-moon conjunction tonight

Tonight (Friday, Jan. 23rd) the moon will pass only about 1°  (two moon diameters) south of Comet 15P/Finlay as seen from the Americas. This map shows the view from the upper Midwest at 7 p.m. Two 6th magnitude stars in Pisces are labelled. Created with Chris Marriott’s SkyMap software

I want to alert you to a rather unusual event occurring this evening.

If you read yesterday’s blog, you know about the triple shadow transit of Jupiter’s moons Io, Europa and Callisto. That’s scheduled for late tonight.

Earlier, around nightfall, the crescent moon will lie 1° or less to the south-southwest of comet 15P/Finlay. No doubt lunar glare will hamper the view some, but what a fun opportunity to use the moon to find a comet.

The farther south you live, the closer the moon will approach the comet tonight. This diagram shows the view from Tucson, Ariz. at nightfall when less than 1/2° will separate the two. At about the same time (~7 p.m. local time) the moon will occult or cover up a 6th magnitude star (seen poking out from its left side). Source: SkyMap

Finlay underwent a flare in brightness last week when it became easily visible in binoculars.

Though a crescent moon isn’t what you’d call a glare bomb, I can’t predict for certain whether you’ll still see the comet in binoculars tonight or need a small telescope instead. Most likely a scope. Finlay has faded some since its outburst and now glows around magnitude +8.5.

You can try with a 10×50 or larger glass, and if you don’t succeed, whip out your telescope; a 4.5-inch or larger instrument should handle the job. Just point it at the moon at star-hop a little to the north-northeast using the map until you see a fuzzy spot with a brighter center. That’s your comet. The tail won’t be visible unless you’re using more firepower, something closer to 10-inches.

Comet Finlay in outburst on January 20, 2015 showing a beautiful parabolic-shaped head. Credit: Joseph Brimacombe

By the way, the father south you live, the closer the moon approaches Finlay. From the far southern U.S. they’ll be just 1/2° apart. Keep going south and parts of Central and South America will actually see the earth-lit edge of moon approach and then occult the comet from view!

* UPDATE: Although light clouds marred the view I had difficulty finding the comet this evening in my 10-inch scope. It’s possible it’s further faded or my conditions weren’t optimal or both. No luck BTW in binoculars.

Mars has close brush with Neptune tonight

Binocular view (~5 field) of Mars, Neptune and nearby stars this evening. The planets will be very close together – only one-fifth of a full moon diameter apart. Mars is bright, but Neptune will look like a faint star to the planet’s upper right. Stars shown to magnitude +8.5. Source: Stellarium

Mars has been hiding away in Aquarius low in the southwestern sky at dusk minding its own business. But tonight however the Red Planet will pass VERY close to another more distant planet, Neptune.

To find Mars you’ll need an open view to the southwest. This map shows the sky facing southwest at the end of evening twilight. Mars is about 12-15° above the horizon at that time. Diphda is a fairly bright star in the constellation Cetus the Sea Monster. Source: Stellarium

You can see the “double planet” faintly in 10×50 or larger binoculars but a small telescope will make it a snap. The chart shows a binocular view just the way you’d see the scene facing southwest at nightfall with north toward the upper right. The best time to view the conjunction will be at the end of twilight when they’re highest.

Track of Mars in the next few days as it glides by the planet Neptune. This is also a 5° field of view similar to what you’d see in a pair of binoculars. Created with Chris Marriott’s SkyMap software

Also in your binocular view you’ll see the stars Sigma and 58 Aquarii. Neptune will look exactly like a star and surprisingly close to Mars.

Waning moon moons Saturn at dawn tomorrow

Saturn lies just a degree from Beta Scorpii, a fine double star for small telescopes. Tomorrow morning a waning lunar crescent will join the pair in a fairly close conjunction. This photo shows the sky facing southeast at the start of morning twilight. Credit: Bob King

Have you seen Saturn at dawn yet? No? Here’s a great excuse to go out. The waning crescent moon squeaks just 1° north of the planet tomorrow morning in a close conjunction. It all happens not far from Antares, the fiery heart of the summertime constellation Scorpius the Scorpion.

Look low in the southeast tomorrow morning (Friday) Jan. 16th just when the sky starts to brighten at dawn. First you’ll notice the moon. Right below it will be Saturn, and one degree below Saturn, the sweet double star Beta Scorpii. Source: Stellarium

I know that getting up at 6 or 6:30′s not much fun, but I’m convinced that if you act boldly and wisely (dress well for the cold), you’ll return to the warmth of your home a half-hour later with a smile on your face.

Seeing the conjunction requires no optical aid whatsoever, though a pair of binoculars will show nice details on the moon as well the smoky glow of earthshine on the portion not illuminated by the Sun. Saturn requires only a telescope magnifying 30x or higher for a good view.

Saturn, its fab rings and brightness moons depicted for Friday morning. Source: Stellarium

While we’ve been sleeping, Saturn’s rings have been tilting ever more in our direction. Now at mid-month, they’re tipped nearly 25° – almost to their 27° max – and really look showy.

Saturn never travels alone, preferring instead to sally about with its grand family of moons. The diagram above shows the positions of the brightest ones tomorrow morning around 6:30 a.m. (CST).

Saturn in late August 2014. We currently view the north face of the rings. Credit: Paul Maxson

Finally, you’ll notice a modestly bright star just south of Saturn. That’s Beta Scorpii or Graffias, one of the sky’s best and brightest double stars. The 2.6 and 4.5 magnitude stars nestle together like chicks in a nest. Even a 3-inch telescope will show them.

So get out there and say “hi!” to the ringed planet tomorrow.

Moon perambulates with Uranus tonight

The half-moon creeps up on the planet Uranus this evening. The two will be near each other all night in the constellation Pisces, but closest – less than one-third of a moon diameter apart – just before midnight (CST). The views are what you’ll see in a pair of binoculars. The 4th magnitude star Delta Piscium is at top in the field. Source: Stellarium

Sunlight. Moonlight. Starlight. I saw all three for the first time in weeks yesterday. Filled with photons, I feel lighter today, less burdened. Ready to float off the floor.

Seattle, two time zones west of the Midwest, will see the two closest around 9:30 p.m. local time. Source: Stellarium

There’s a nice event you’ll want to see tonight if only because it’s so effortless. The half-moon will pass very close to the planet Uranus for skywatchers across North America this Sunday evening Dec. 28th.

Pop the rubber lens caps off those binoculars and point them at the moon. If you look a short distance to the left you’ll notice a star-like object. That’s the planet!

You can do this anytime it’s dark, but the later you look the better because the moon moves eastward and closer to the planet as the hours tick by. Early in the evening, the two will be separated by a couple degrees, but around 11:30 p.m. CST (9:30 p.m. PST) when the moon reclines in the western sky, the planet will dangle like an solitary diamond less than a third of a lunar diameter away. When closest to the Moon, Uranus may prove tricky to see in its glare. If you hide the Moon behind a chimney, roofline or power pole, you’ll find it easier to see the planet.

Binocular view from the desert city of Tucson around 10:45 p.m. local time tonight. The moon’s farther north of the planet compared to the view from Seattle because the 1,500 miles between the two cities is enough to shift the moon’s position against the background stars. Source: Stellarium

The farther north you live, the closer the twain will be. Skywatchers in Japan, the northeastern portion of Russia, northern Canada and Alaska will see the moon completely hide Uranus for a time.

The farther west you are, the higher the moon will be when they conjoin. West Coast states see the pair highest when they’re closest.

The radically different character of each world can best be appreciated in a telescope. Pump the magnification up to 150x and slide both planet and moon into the same field of view. Uranus, a pale blue dot, wears a permanent cover of methane-laced clouds where temperatures hover around -350°F (-212°C).

Though the moon will be lower in the sky at closest approach, observers in the eastern U.S. and Canada will still see planet and moon just 1/2 degree apart before moonset. Source: Stellarium

The fantastically large-appearing moon in contrast has precious little atmosphere and its sunny terrain bakes at 250°F (121°C). And just look at those craters! First-quarter phase is one of the best times for moon viewing because the terminator or shadow-line that divides lunar day from night slices right across the middle of the lunar landscape.

Shadows cast by mountain peaks and crater rims are longest and most dramatic around this time because we look squarely down upon them. At crescent and gibbous phases, the terminator is off to one side and craters and their shadows appear scrunched and foreshortened.

The day-night line or terminator cuts across a magnificent landscape rich with craters and mountain ranges emerging from the lunar night. Several prominent lunar “seas” or maria and prominent craters are shown. Credit: Christian Legrand and Patrick Chevalley / Virtual Moon Atlas

Enjoy the view and consider the depth of space your view encompasses. Uranus is 1.85 billion miles from Earth today — 7,700 times farther away than the half moon.

Venus returns, joins exceptionally young moon tonight

Look low in the southwestern sky starting about 20 minutes after sunset this evening for a little spark of light – Venus. About 5° (one binocular field of view) to its upper right you might glimpse the moon, just 20 hours old from the East Coast (21 hours from the Midwest, 22 hours from the mountain states and 23 hours from the West Coast.) Source: Stellarium

Have you noticed something missing lately? Venus has been absent from view since late last summer. We last saw it struggling against the solar glare at dawn.

Now, just in time for the holidays, Venus is returning to the evening sky, low in the southwest after sundown. Tonight there’s even a chance to see it next to an exceptionally thin crescent moon.

Look for the goddess of beauty and love to meet up with the moon some 20 minutes after sundown low in the southwestern sky. Most of us consider seeing a day-old crescent moon quite a feat, but from the Midwest this evening, Luna will be just 21 hours old, a fragile crust if ever there was and a chance to break your personal young moon record.

I’d bring binoculars just to be sure you see the two. Venus will be only 6° above the horizon this evening. Make slow horizontal sweeps with your binoculars to the left of the brightest part of the lingering glow of sunset. As long as the sky is haze-free, Venus should pop into view. Once you’ve nailed it, move to the upper right in the field of view and locate the moon. Now, lower the binoculars and try sighting both with your naked eye alone.

Venus revolves around the Sun interior to Earth’s orbit. Right now it’s still near its greatest distance from Earth on the opposite side of the Sun from us. Over the coming weeks and month, it will draw closer to Earth and grow in apparent size as its phase changes from full to crescent. Source: Wikipedia with additions by the author

Venus underwent superior conjunction on October 25th, when it lined up with the Sun on the opposite side of its orbit from Earth. It was most distant from us then and appeared like a tiny full moon. The planet’s still pretty far away and will remain near the Sun in evening twilight for the next month or so. Although Venus’ orbital speed varies little over its nearly circular orbit, it appears to travel very slowly this winter because it’s very far from us.

Fear not! Its appearance this month is a harbinger for this spring and early summer’s exceptional apparition when the brightest of the planets will catch your eye in the west all evening long.

Looking at the diagram, notice that Venus, moving faster than Earth because it’s closer to the Sun, is slowly catching up with our planet. As it does, the angle it makes to Sun and Earth continuously changes which changes the appearance of Venus. Through a small telescope we can easily see its phase shrink from full to half to crescent exactly like the phases of the moon.

Panels illustrating several of the closest and best conjunctions of Venus and the planets in the coming year. Source: Stellarium

Venus is famous creating spectacular scenes with other bright planets and the moon. We call these events conjunctions. I’ve illustrated a few of them above. The best will occur on July 1st when the sky’s two brightest planets will be just 0.4° apart.

I love it when Venus returns to view. It always puts a bright face on every clear night.

Moon and illusion in the Hyades tonight

The waning gibbous moon moves across the Hyades star cluster tonight October 11. This map shows the view through binoculars around 10 p.m. CDT. Moon is to scale. Source: Stellarium

Now that the eclipse is behind us, the moon has trotted off to the east out of the limelight.

It’s in that lengthly phase called waning gibbous, a period of 6+ days between full moon and last quarter. Can I coax you out for another look?

Tonight the moon will cross the Hyades star cluster that forms the V-shaped face of Taurus the Bull. Merely having the moon in Taurus hints at how close we are to the start of winter. Two months hence, the Bull, along with Orion the Hunter, will dominate the southern sky at 10 o’clock.

Taurus the Bull from the 19th century star atlas Urania’s Mirror.

But tonight around 10, Taurus makes its appearance in the eastern sky. Because the moon is still fat and bright you’ll better appreciate its passage through the Hyades with binoculars. By happy circumstance, the entire cluster neatly fits into the field of view of most pairs.

Orange-red Aldebaran is Taurus’ brightest star and completes the cluster’s V with a flourish. Don’t be deceived. This star is an impostor that by chance lies in the same line of sight as the star cluster. The Hyades form a gravitationally bound group of stars 153 light years distant and were born from the same cloud of gas and dust 625 million years ago. Aldebaran? Only 65 light years away and as solitary as our sun.

The moon moves its own diameter every hour as it orbits the Earth. You can see that motion overnight tonight as the moon approaches and then conjuncts with Aldebaran tomorrow morning. The map shows the view from northern Minnesota / Wisconsin. Source: Stellarium

Over the course of the night, the moon will slowly work its way across the Bull’s face, occulting or covering a number of fainter cluster stars along the way. One such star is 63 Tauri shining at magnitude +5.6. A small telescope 4-inches or larger will show the moon creep up to the star and suddenly blank it from view around 10:10 p.m. Central Daylight Time. Depending on your location, the moon’s path across the Hyades will shift a little north or south, and you may see different stars occulted.

Aldebaran-Sun comparison. Aldebaran is an orange giant star 44 times the sun’s size. The sun will also puff out like Aldebaran several billion years in the future when it starts burning helium in its core as Aldebaran is today. Credit: Wikipedia

By 5 a.m. CDT tomorrow morning Oct. 12 the moon will be in conjunction with Aldebaran about 1º to its north. Here we see yet another of nature’s illusions. The moon not only outshines Aldebaran by 26,000 times, it’s huge in comparison. But make no mistake, Aldebaran’s the giant here. Next to it, the sun looks puny and faint.

With a diameter 44 times solar, Aldebaran’s searing orange photosphere would reach all the way to the planet Mercury if put in place of the sun and overall shine 500 times as bright.

Another noteworthy star to look for in your binoculars is the pair called Theta 1,2 Tauri. Both belong to the Hyades although small uncertainties in their distances make it unclear if they’re a physical double star or like Aldebaran, a chance alignment. Once the moon’s out of the way, this is a fun star to try and split with your naked eye. Like two tiny pearls in a starry brooch, they make for a pleasing sight.

To twinkle or not to twinkle, that is the question

Venus passes Regulus on the morning of September 5. Look low in the eastern sky 30-45 minutes before sunrise to see the pair. Bring binoculars in case twilight overwhelms Regulus. Stellarium

Early Friday morning September 5, skywatchers will see Venus and Leo’s brightest star Regulus in a close conjunction. The two will be separated by just 1° and look very nice in binoculars. Find a place with a view down to the eastern horizon and start looking about 40 minutes before sunrise. Jupiter, higher up in a darker sky, can help guide you to Venus.

This will be Venus’ last encounter with a bright star at dawn before it’s lost in the glare of the sun. It’s often said that one way you can tell a planet from a star is that a planet’s light appears steady, while stars twinkle. Not always. Stars only appear as points of light even through the largest telescopes and are easily shoved this way and that by air turbulence. These tiny shifts in position are what cause twinkling.

When we look at stars low in the sky we look across hundreds of miles of air in the lower, densest part of the atmosphere. Air currents across that great distance push a star’s light around causing it to twinkle. It can have the same effect on bright, naked eye planets when they’re far away and show a smaller than usual disk. Credit: Bob King

Planets have measurable disks and are less affected by the flutter of air, so we rarely catch them shimmering. But when the planet is far from Earth and very low in the sky, the rules change. Both Venus and Mars range in size from tiny blips to substantial disks (or in the case of Venus, a substantial half-moon or crescent). When viewed at low altitude, I’ve seen both twinkle lively.

Illustration showing how a planet, with a measurable disk, defeats air turbulence compared to a star which appears as a tiny point of light through a telescope. Credit: Bob King with Jupiter pic by Damian Peach

I witnessed it last Thursday morning with Venus. Jupiter, larger and higher in the sky, was a steady beacon. Venus, now nearly on the opposite side of the sun from Earth and about as small as it ever gets, trembled like a flame in the wind. What will you see Friday morning?

Venus remains visible for another two weeks before it’s lost in the solar glare. We won’t see the planet at all for more than a month until it returns to the evening sky around Thanksgiving in November. Watch for it to shake and shimmy its way up the western sky until fattening up around Christmas.

Miss the conjunction? Here’s your consolation prize

Clear skies prevailed over Königswinter, Germany for a great view of Venus and Jupiter just 0.2° apart at dawn this morning August 18. Credit: Daniel Fischer

Those killers of all things astronomical – clouds – were back again this morning, so no Venus-Jupiter conjunction here. Looks like I’ll pin my hopes on the one scheduled for next June 30 in Leo at dusk. I’m grateful for the flatness of the solar system, which guarantees that every few years we get repeat planet pairings.

Look east this coming Saturday morning for a sweet pairing of the bright planets and wiry crescent moon. This view shows the sky about 45 minutes before sunrise. Stellarium

I hope some of you got to see the conjunction from your home or on the way to work this morning. While Venus and Jupiter will now part ways, they’ll be one more blast of celestial awesomeness involving the duo and the crescent moon this weekend. Consider it a consolation prize. Who knows, this event might be even prettier than what passed this morning.

On Saturday morning, August 23rd about 30-45 minutes before sunrise, the thin, waning lunar crescent joins Jupiter and Venus in a stunning triangle of loveliness in the eastern sky.The threesome will all fit inside an 8° circle.

Now that I know this is coming I don’t feel so bad about missing the conjunction.

Jupiter and Venus cozy up for year’s best conjunction

The sky’s two brightest planets, Jupiter and Venus, will approach with 0.3 degrees of each other in morning twilight on Monday August 18th, the closest conjunction of the pair visible over North America since April 1998. This view faces northeast about 40 minutes before sunrise. Stellarium

As Mars approaches Saturn at dusk, Jupiter and Venus are zeroing in on each other at dawn for a spectacular close conjunction Monday morning August 18th. You won’t want to miss this one.

Conjunctions of the two brightest planets occur about once every 13 months but vary in visibility (some happen in daylight) and separation. The closer they get, the more arresting the view.

Tomorrow morning the planets will be a little more than 1º (two full moon diameters apart) – righteously close. But Monday morning they’ll be three times closer, just 0.3º  apart or a tad more than a half moon. That’s cozy enough for both to comfortably fit in the same field of view of a telescope.

Want to watch the approach? This view shows the sky tomorrow morning Sunday August 17th about 45 minutes before sunrise facing northeast. Venus will be about a degree above Jupiter and shine six times brighter.  Stellarium

To watch the event, find a place with a wide-open view to the east as far down to the horizon as possible.

Both planets will about 8º high or just shy of a fist held at arm’s length 40-45 minutes before sunrise.

Bring your camera too! A mobile phone might do OK in twilight, otherwise set your camera’s ISO to 400, place it on a tripod and open the lens to f/4 or 4.5. Then in auto mode, focus your lens at infinity by pointing it at the moon or a cloud. Now click your lens back into manual focus mode and point it at the planets, making a series of exposures from 1 second to 10 seconds. Check the camera back to make sure you’re in the ballpark on both sharpness and exposure.

Jupiter (top) and Venus in a more distant conjunction on June 30, 2012 seen over Lake Superior in Duluth, Minn. Credit: Bob King

Close as Jupiter and Venus will be for North America, skywatchers in central Europe will see them even closer (0.2º) before sunrise. After Monday, Jupiter continues its swift rise in the eastern sky while Venus slowly sinks toward the sun. They won’t pair up again until June 30, 2015 when they’ll be just as close in evening twilight in the constellation Leo.

Venus and Jupiter will pair up right next door to the Beehive Cluster in Cancer Monday August 18th at dawn. This shows an approximate binocular view. Stellarium

One final and happy note. Not only are the planets pairing up, they also happen to be right next to the Beehive star cluster in the constellation Cancer the Crab. I think you’ll need binoculars to see the cluster clearly, so be sure to have a pair along.

It should be a fun morning. The only down side is that it’s a Monday, meaning you’ll need a nap by the afternoon.

Mars and Saturn boogaloo with Zubenelgenubi

Mars and Saturn are now only about 7 degrees apart (a little more than three fingers) low in the southwestern sky at dusk. This view shows the sky about 90 minutes after sunset. Between the two, you can spot the dimmer star Zubenelgenubi, the brightest star in the constellation Libra the Scales. Stellarium

Evening planets Saturn and Mars are fading and dropping lower in the western sky as August ticks toward September. Remember when Mars was brighter than Arcturus this spring? Planets. They never sit still. Their light’s never constant. We love watching them change, which is why our ancient ancestors knew immediately they were different from the static stars.

From my house, I need to be vigilant to spot Saturn and Mars before they’re lost in the treetops. That means getting out about an hour after sunset in fading twilight and finding an open spot where I can look low in the southwestern sky.

You may have noticed that the two have slowly been drawing together over the past few weeks. Mars, much closer to Earth than Saturn, moves more quickly across the sky. It’s been ‘chasing’ slower Saturn for some time now.

Mars gets closer to Saturn with each passing night until August 25 when they’ll be in conjunction just 3.4 degrees apart (twice as close as tonight). Watching Mars move against much slower Saturn makes a fun and easy observing project. Stellarium

Tonight, the two planets will be 7 degrees apart on either side of Libra the Scales’ brightest star, Zubenelgenubi (zoo-BEN-el-je-NEW-bee). The name, a delight to pronounce, is pure Arabic and means ‘southern claw’. Libra’s stars used to belong to neighboring Scorpius and both it and nearby Zubeneschamali (northern claw) remind of us of times long ago when Libra belonged to Scorpius.

Zubenelgenubi (a.k.a. Alpha Librae) is a double star that observers with keen vision can split with the naked eye. Most of us will find that a pair of binoculars will make the job much easier.

Mars will soon pass its slower brother but not before the two are in conjunction and closest together on the evening of August 25th. Watching two planets pass in the night is fun and instructive – it makes us aware that everything in our solar system’s on the move.

This weekend we’ll look at another even more amazing planetary conjunction coming up very soon – Jupiter and Venus on August 18.