The Moon and Jupiter

This evening at sunset a nice crescent Moon and the bright planet Jupiter will be quite close. As sunset around 19:00 the two will be separated by a mere 46′, just a little over the width of the full Moon. The two should make a very attractive pair as they sit above the glow of sunset.

Keep an eye out for Mercury and Venus closer to the horizon. At 19:00 Venus will be 9° above the horizon with Mercury a bit higher at 14°. The Moon and Jupiter will be higher yet around 25°. Since Mars and Saturn are also visible in the southern sky all five naked eye planets will be visible.

All Five Planets Visible

For much of the month all five naked eye planets will be visible at sunset. Mercury, Venus, Mars, Saturn, and Jupiter can all be seen easily if one knows where to look. Indeed, four of the five are quite bright and quite hard to miss. Neptune and Uranus are generally too faint to be seen without optical aid.

Venus and Jupiter over the Keck 1 dome
Tonight, August 1st, Venus is just rising high enough to be easily seen. It will be a mere 5° above the horizon at 19:30, probably bright enough to be seen against the glow. You can find Mercury a little higher, about 10° above the horizon. Jupiter is obvious well above the sunset as a bright object shining at -1.7 magnitude. Mars and Saturn are visible to the south on the top of Scorpio.

There will be a nice conjunction of the Moon and Jupiter, only 46′ apart, on the 5th of August. Mercury reaches eastern elongation on the 16th of the month. A beautiful triplet of Mercury, Venus, and Jupiter will gather in the days around the 22nd. Keep an eye to the sky for the month to be treated to some nice planetary views.

Five Bright Planets in the Dawn

All five planets that are visible to the unaided eye can be found in the dawn for the next few weeks. Jupiter, Saturn, Venus and Mars have been visible in the dawn for some time now. Arriving late to the party is Mercury, just rising out of the glow of dawn. Mercury is headed for maximum elongation on February 7th, rising to 24° ahead of the rising Sun. The line of planets will persist for a week or two after that as Mercury drops back into the glow of dawn after elongation.

Zodiacal Light
False dawn, actually zodiacal light, rising over Mauna Kea
Highest in the sky is Jupiter, shining at -2.3 magnitude and rising before 10pm. Mars rises next, around 1am, seen as a ruddy red object, much dimmer at +1 magnitude. Saturn will rise around 3:30am in Scorpio near Antares, shining at +0.5 magnitude. Venus rises around 4:45am and will be quite obvious, the brightest of the five at -4 magnitude. Last will be Mercury, currently rising just before 6am and shining at +1.2 magnitude. It will rise earlier and earlier as it approaches maximum elongation, rising at 5:20am on February 7th. As Mercury reaches it highest it will be only 4° from Venus.

Together the five planets neatly outline the ecliptic, the plane of our solar system revealed by simply connecting the dots across the sky. As dawn approaches, but before the start of twilight around 6am, look for the zodiacal light, the bright glow of interplanetary dust also seen along the ecliptic.

Venus and Saturn

On the morning of January 8th and 9th Venus and Saturn will be quite close in the dawn.

Moon and Mercury
The Moon appears as a thin crescent beside the planet Mercury, photo taken from the summit of Mauna Kea on 12Oct2007
Tomorrow morning the two can be seen rapidly closing upon each other, less than 3° apart. A slim crescent Moon will be only 4° above Venus making for a lovely trio in the dawn. The morning of the 7th will also feature a nice trio, with the Moon now below the pair, closer to the horizon.

As the pair rises on the morning of the 8th they will be only 32′ apart, easily close enough to fit in the low power field of most amateur telescopes. The morning of the 9th will see the pair again close, only 34′ separation. They will slide past each other much closer, about 5′ apart, but this will not be visible from the central Pacific as it occurs around 11:42 HST on the 8th, while the planets are below the horizon.

Moon, Venus and Saturn

Tomorrow’s dawn, January 6th, will see the Moon, Venus and Saturn in a nice conjunction. A beautiful 12% illuminated crescent Moon will be a bit over 4° above Venus shining brightly at -4 magnituide. Saturn will be another 3° below Venus. As an added accent the bright star Antares will be 6° south of the trio.

The Moon and Saturn

There will be a close approach of the Moon and Saturn tonight and tomorrow. At sunset on the 9th the pair will be separated by less than 7° and found well up in the eastern sky. As the night progresses the pair will slowly close the gap. As the pair sets around 03:30 the morning of the 10th, the separation will have been reduced to about 4°. As the two rise on the evening of the 10th they will have passed and the separation will be increasing. At sunset the pair will be 7° apart.

Viewers on the other side of our planet will be able to observe the closest approach, much less than a degree for many, an occultation if you happen to be in the right place. Sky watchers in Capetown, South Africa will see the planet disappear behind the limb of the Moon for about an hour around 19:11UT.

The Moon and Saturn

Tonight the planet Saturn will be quite close to the Moon. The pair will rise about 18:20 HST and be well up in the east in the late evening. Look for 0.1 magnitude object just north of the Moon, there are no nearby stars bright enough to confuse for the planet. The Moon is full at 09:16HST tomorrow, just short of full for tonight’s pairing.

Observers in the islands will see the Moon pass less than 1° south of the planet during the early morning hours of the 14th. Observers in the southern hemisphere will be able to view an occultation if at the correct latitude, check a planetarium program for the view from your location.

Saturn at Opposition

Today the planet Saturn will pass through opposition, directly opposite the Sun in our sky.

Saturn 22Apr2010
Saturn with Titan above
Saturn orbits the Sun once every 29.45 years. As the ringed planet continues on its way the Earth swings around much faster on our inside track. As a result we lap Saturn once every 378.1 days, passing between the planet and the Sun. During opposition Saturn will be well placed for observation all night long, rising at sunset, transiting at midnight, and setting at sunrise.

During opposition the planet and rings will be slightly brighter than normal, an effect known as the opposition effect. The effect is most notable in the rings where the apparent brightness can increase by 30%. The effect is a combination of two factors, shadow hiding and the retro-reflective properties of the ring particles.

The Moon and Saturn

Tomorrow morning, Feb 21st, the Moon will be in close attendance with Saturn, separated by a little under 4°. The two will be high in southern the sky before dawn, a last quarter Moon will be 61% illuminated. Saturn can be seen as a 0.5 magnitude object just East of the Moon and west of the head of Scorpio. The following morning, Feb 22nd, the Moon will have moved to the other side of the ringed planet with a separation of just over 8°.

Viewers on the other side of the world will be able to see a very close pairing of the two, less than half a degree apart or even in occultaion depending on location. Close approach will be about 14:00 HST on the 21st. You could make an attempt to view the pair in the daytime sky, Saturn is bright enough to be seen next to the Moon in a modest telescope or even a good pair of binoculars. Unfortunately the Moon sets around 11:00, a few hours before close approach here in the islands.