Summer Nights

The nights are finally getting longer again, not that you’ll really notice until late July, and the latest sunset of the year is Saturday this week. Also on Saturday the Moon is to the lower left of Saturn, there’s a guide on the blog

And this is quite an interesting month if you can stay awake, or are out in the early hour’s breaking and entering, Barbara. Because during the second half of June, six of the seven planets (not counting Earth) are positioned at dawn within a 100° span of sky, from low in the east to fairly high in the south. From left to right they're Mercury, the Venus-Mars pair, Uranus, and the Jupiter-Neptune pair, only Saturn isn’t joining the party

This comes 25 years after very the rare gathering of all seven planets — and then-planet Pluto — into a span of only 60° in January 1984.

But as usual it’s all happening in the predawn, between 3 and 4 am, over to the east.

We have a new moon this week and after 12:30 fairly dark skies, and with the arrival of summer, the Milky Way now arches across the eastern heavens after the last lingering twilight finally fades away. The Milky Way runs from Cassiopeia low in the north-northeast through lower Cepheus, then across Cygnus, the Summer Triangle, and Aquila, and down to Sagittarius and Scorpio in the south-southeast. It should be obvious as a bright arch over head.

Mercury is having a poor apparition deep in the glow of dawn. Look for it in morning twilight about 25° lower left of Venus and Mars. Binoculars will help.

Venus and Mars remain together due east during dawn. Venus is a dazzler; but Mars is getting brighter and is now only about 150 times fainter than Venus. They're only 2° or 3° apart this week, hardly more than a finger's width at arm's length. June 22nd was their conjunction date, when they're separated by 2.0°. Look for Mars to directly above Venus later in the week

Jupiter in Capricorn now rises before midnight and shines brightly in the south by dawn. The sharpest telescopic glimpses may come during morning twilight, when the atmospheric seeing sometimes turns very steady.

Saturn is still the only planet showing in the evening sky, and it’s still fairly dim because all year the rings' tilt to the Sun has been steadily decreasing, and accordingly, the rings have been getting darker and darker. Saturn is now becoming harder to observe as it moves lower in the west each evening.

Uranus is Pisces is between Venus and Jupiter before dawn.

Neptune in Capricorn remains only 3/4° from Jupiter, but it's 16,000 times fainter. And will be difficult to spot even with Binoculars

You may have noticed over the course of the last 18 months or so, that the planets tend to hang around the constellations of the zodiac, this is no coincidence. The solar system is essentially a huge flat disc centred on the sun and the constellations of the zodiac are on the same plane. The sun is in cancer at the moment, a constellation we obviously can’t see at the moment, Saturn is in Leo, Uranus is in Pisces and Jupiter is in Capricorn. The moon also moves through the Zodiac, hence there are endless variations of mumbo jumbo to be derived from all the limitless permutations.

Summer

Winter

Summer

This week’s major event has to be summer starting early on Saturday morning; the Solstice is on the 20th this year. So on Saturday night we begin the inexorably plunge back to midwinter. At the winter Solstice the North Pole is tilted 23 and a half degrees away from the sun and the sun is always over the horizon, at summer solstice it’s tilted 23.5 degrees the other way and the sun never sets. So the divergence between mid winter and midsummer is a massive 47 degrees which goes some way to explain the huge difference. At noon on Saturday the sun will be almost 80 degrees above the horizon in midwinter it barely scrapes 31, and if you imagine a compass Sunrise on the Summer solstice is diametrically opposite Sun Set on the winter solstice, and we get about 8 hours more daylight.

Another thing you may have noticed is that the length of the day isn’t changing much at all at the moment, the sun’s been setting at about 9:30 for more than a month. This is best explained if you think of the change in seasons as a pendulum. At the moment the days are still getting longer but on Saturday it all stops and goes in to reverse, the pendulum reaches the top of its swing. It starts falling back and accelerates to the bottom of its swing at the equinox in September when it changes by up to 4 minutes a day. It then starts decelerating to ward the winter solstice after which it then starts to fall away again toward the spring.

There are a number of distinct overlapping periods during the yearly cycle, in winter and Spring the days are lengthening, and shortening during Summer and Winter, during Autumn and Winter the nights are longer the days and vice versa in Spring and Summer. It’s a combination of two variables define the seasons, day compared to night and lengthening or shortening, which. In winter days are lengthening but nights are longer, spring days are lengthening but nights are shorter. In summer nights are lengthening but days are longer, and autumn gives us the worst of both worlds, longer and lengthening nights.

All this is pretty obvious if you think about it, and I’ve just used nearly 400 words to tell you summer starts early Saturday morning, but then again there’s not much else going on this week, unless you’re out and about between 3 and 4am.


During dawn Friday morning the crescent Moon hangs about 6° above Venus and Mars.

At the end of the official Midsummer Night, busy things are happening at dawn Sunday morning. About 45 minutes before, you can spot a very bright Venus in the east with faint little Mars just to its upper left. Using binoculars, look well left of Venus for the Pleiades, and look about 24° to Venus's lower left to pick up the thin crescent Moon and look lower right of the Moon for Mercury.

Jupiter is rising earlier all the time and now appears in the east before midnight and shines brightly in the south by dawn.

As Jupiter is in the ascent, we’re slowly loosing Saturn; it’s in the southwest at dusk and sinks lower in the west as the evening advances.

The vivid meteor shower on Tuesday night could have been one of three showers forecast: for June, meteor showers happen when the earth crosses the orbital path of a comet. If the comet happens to be there at the same time we get a mass extinction and nobody sees much of anything at all.

The Mars Email

MARS The Red Planet is about to be spectacular in August of 2009! This month and next, Earth is catching up with Mars in an encounter that will culminate in the closest approach between the two planets in recorded history. The next time Mars may come this close is in 2287. Due to the way Jupiter's gravity tugs on Mars and perturbs its orbit, astronomers can only be certain that Mars has not come this close to Earth in the Last 5,000 years, but it may be as long as 60,000 years before it happens again. The encounter will culminate on August 27th 2009 when Mars comes to within 34,649,589 miles of Earth and will be (next to the moon) the brightest object in the night sky. It will attain a magnitude of -2.9 and will appear 25.11 arc seconds wide. At a modest 75-power magnification Mars will look as large as the full moon to the naked eye. Mars will be easy to spot. At the beginning of August 2009 it will rise in the east at 10 PM and reach its azimuth at about 3 a.m. By the end of August when the two planets are closest, Mars will rise at nightfall and reach its highest point in the sky at 12:30a.m. That's pretty convenient to see something that no human being has seen in recorded history. So, mark your calendar at the beginning of August to see Mars grow progressively brighter and brighter throughout the month. Share this with your children and grandchildren. NO ONE ALIVE TODAY WILL EVER SEE THIS AGAIN

First this week I’d like to clear something up, I’ve had a few people who’ve ask me about an email that’s been going around about a close encounter with Mars on the 27th of August this year, when Mars will be as close as 34 million miles, and will look as big as the full moon. Well it’s a hoax, at the moment we’re chasing Mars around the Sun, its on the other side at the moment, and a long way away about 250,000,000 miles, which is why its so dim in the dawn sky, we’ll lap it on the 19th of October when it will be only 43,000,000 miles away, it could get as close as 34,000,00 mikes though, if the earth were at its furthest from the sun and Mars was at its closest and in opposition.

The email, tells us that Mars will look as large as the full moon, and ends with “no one alive will ever see this again”, it should be there’ll be no one alive to see anything again. For Mars to be that big it would have to be less than a million miles away, and if it didn’t collide with us, which it almost certainly would, we’d have massive tides, and our orbit would savagely adjusted further out or perhaps further in, which would give us an Indian summer that no one would know about. So it just a pretty harmless joke. It’s a rehash of a real event, another encounter with Mars, six years ago, on August 27, 2003. That was the closest in recorded history, by a whisker, and millions of people watched as the distance between Mars and Earth shrunk to 35 million miles. This October’s encounter, at 43 million miles, is similar. To casual observers, Mars will seem about as bright and beautiful in 2009 as it was in 2003. But sadly there’ll be nobody to see it because we have an asteroid the size of Australia due to hit 4 miles north of Bude early on Sunday morning.

Well it was nice to have something else to talk about, because not much has changed since last week, though it starting to. At last Jupiter is moving up and away from the dawn sky; soon after midnight on Friday, look to the lower left of the waning Moon in the east for Jupiter on the rise, as shown above. They both stand high in the southeast by dawn.

Mercury is both faint and buried deep in the glow of sunrise, very far lower left of Venus, and not worth the effort.
Venus still outshines all the opposition due east during dawn. In a telescope Venus appears about half lit. It's
A very dim Mars in Aries has closed to within only about 4° to Venus's left. But it's 160 times fainter! But as you just heard we’re chasing it and it will improve over the next couple of months
Saturn in Leo is now in the southwest at dusk. It moves lower to the west later in the evening, and pretty soon we’ll lose it altogether, but a much brighter Jupiter will replace it.
Uranus (magnitude 5.9, in Pisces) is between Venus and Jupiter before dawn, but it’s very dim.
Of course all this presupposes at least clear sky’s and I have to say I’m cautiously pessimistic about getting one, that’s the trouble with having sub tropical climate, sometimes the sub takes over.