Not A Lot

Not unexpectedly last week’s Persied meteor shower was obscured by clouds for its entire duration, I did have a look on Friday when the sky was crystal clear just in case there were any late comers, but not a flipping sausage, never mind there’s some more in October.

First up is the Draconids, on the 8th and ninth and then the Orionids, a major shower of shooting stars, on October 20-21.

You’ve probably guessed that there’s not a whole lot going on this week already, or why would I be bleating on about October.

Mercury and Saturn appear near each other in bright twilight just above the horizon due west. Use binoculars to look for them about 30 minutes after sunset. At the beginning of the week Saturn is above Mercury; later it's to Mercury's upper right, check the blog, but even with a clear night you’’ need binoculars.

Venus is in Gemini and blazes in the eastern sky before and during dawn, and is unmistakeable. It’s still about as bright as it was in February when it wasn’t keeping antisocial hours and was setting up to 3 hours after sunset in the west.

Mars still on the dim side but improving rises about an hour and a half before the sun, passing between the horn tips of Taurus is high to the upper right of Venus before dawn. To its own upper right is similar-looking Aldebaran. To its lower right is similarly coloured Betelgeuse, which is the bright star to the top left of Orion. So although Mars will have moved a little by October when Orion returns to the evening star, it will be easily found and at its closest to the earth for a long time.

Jupiter, in Capricorn was at opposition on August 14th. So now it’s with us for the whole night It comes into view low in the southeast early in twilight — the first "star" to appear after sunset. It's higher in better telescopic view by 11 or midnight. You can’t miss it it’s the extremely bright star that arcs across the southern sky throughout the night.

But even with out a blockbuster feature, we’ve still got all the usual stars, and the most spectacular sight at the moment is the Milky Way, it arcs across the sky from north east to the south west and is always worth a look with binoculars, even with poor binoculars you’ll see at least 10 times as many stars. And the Milky Way although it’s a run of the mill spiral galaxy, amongst billions of the things, it still has some pretty impressive statistics.

The stellar disk of the Milky Way galaxy is approximately 100,000 light-years in diameter, and is an average, about 1,000 thick. With between 200 billion 400 billion stars, and its just our look that out of all those stars its our Solar System that produces Britain’s got talent.

Persid Meteor Shower

Persid Meteor Shower

The Perseid meteors appear to stream away from their radiant near the border of Perseus and Cassiopeia. And while you're outside on a dark night, don't forget to look for the Double Cluster and the Andromeda Galaxy, two of the easiest "faint fuzzies" to spot with your unaided eye.

Dawn Sunday/Monday

Jupiter's impact scar is the small dark mark in the planet's South Polar Region (top). The black dot on the edge of the South Equatorial Belt is the shadow of Callisto. Note the Great Red Spot just about to rotate out of sight on the celestial west limb (left). Sky & Telescope's Sean Walker used a 14.5-inch reflector for this stacked-video image 8:45 UT July 23, 2009.

This week’s big issue is the Persied meteor shower. The little bits of interplanetary grit making up the Persied meteoroid stream orbit the Sun with a period of about 130 years, like their object of origin, Comet 109P/Swift-Tuttle. The richest part of the stream is strung out near the comet itself, which last dipped through the inner solar system in 1992. So the shower's annual sky show has waned of late —the great Persied meteor displays of the early 1990s are gone.

This year's Persied peak was predicted to come around 18h Universal between 11pm and dawn last night. But there should be still a few around for a few days yet. After 10 pm look to the north east for the radiant, straight down a few degrees from the first star in the Cassiopeia W, an easy constellation to spot, a misshapen W. There’s a diagram on the blog.

The waning Moon is nearly at last quarter. It rises an hour or two after dark and will brighten the sky somewhat during the best Persied-activity hours, from 11 p.m. until dawn. Nevertheless, but this is a pretty reliable shower, and some Perseids should be there for the catching.

If you’re really serious about Meteor watching, I found some instructions on S and T.com. Find a spot with an open view of the sky, wrap up warmly in winter clothes, perhaps an anorak or a sleeping bag, and use mosquito repellent where you're not wrapped. Lie back in a lounge chair and watch whatever part of your sky is darkest. Be patient. You may see a meteor zipping into the upper atmosphere every few minutes on average.

On Friday, Jupiter is at opposition, big and bright. It's opposite the Sun in the sky: rising around sunset, shining highest in the middle of the night, and setting around sunrise. And I’ve put a nice picture of Jupiter’s new black spot up on the blog.

During Sunday’s dawn morning the thin waning crescent Moon hangs with Mars, when early risers can watch the waning crescent Moon pass Mars and then Venus in the dawn. there’s a guide on the blog.

You can still catch Venus blazing away in the dawn sky, with Mars nearby between the horns of Taurus, but bear in mind they’re only horns if you have a vivid imagination or know a horribly misshapen bull.

Green Flash

Remains the same much of the week, for both images.

Green Flash

Tonight we have a full moon, the last but one of this summer and we have a slight penumbral eclipse, which means only a very slight dimming probably, too slight for any shading to be detectable at all by eye. If you want to try and spot it, the mid point is at 1:40am. If you can’t see it never mind, Jupiter will be easily visible near the moon, for the next two or three days.

I haven’t checked the tides, the bus is strangely unaffected by them, but I imagine they should be pretty big this week, with Jupiter the moon and the sun lining up, though Jupiter being so far away will only add a couple of inches.

On Thursday, the Moon rises in the dusk with a menacing Jupiter just 4° to its right.
Mercury is having a poor apparition deep in the glow of sunset. Look for it very low in the west-northwest in bright twilight.


Venus in the feet of Gemini blazes in the eastern sky before and during dawn.
As recently happened with Jupiter, an amateur planetary imager has found a newly-appeared marking on Venus! Frank Melillo of Holtsville, New York, discovered that Venus had unexpectedly grown a "Great White Spot" in ultraviolet light when he imaged it on the morning of July 19th. The European Space Agency's Venus Express probe, currently orbiting Venus, has imaged the spot in detail.

Mars getting a little brighter now, in the horns of Taurus is well to the upper right of Venus before dawn. Not far to Mars's right or upper right is Aldebaran, a close match for it in both brightness and color. The two are 7° apart on August 1st, 10° apart by the 8th.
Jupiter very bright in Capricorn shines low in the east-southeast during twilight. It's higher the southeast by midnight.

Saturn (magnitude +1.1, in Leo) is getting very low in the west after sunset. Pretty well lost to us now, and the rings have about vanished. They turn edge-on to the Sun and go black on August 9–10.

Now I’m about to take all the romance out of the fabled green flash. The reason for a green flash lies in refraction of light in the atmosphere, light moves more slowly in the lower, denser air than in the thinner air above, so sunlight rays follow paths that curve slightly, in the same direction as the curvature of the Earth. Higher frequency light (green/blue) curves more than lower frequency light (red/orange), so green/blue rays from the upper limb of the setting sun remain visible after the red rays are obstructed by the curvature of the earth. I’ve put a lovely picture on the blog which I’d love to say I took, but I didn’t
Though if you firmly believe it’s an omen for the imminent end of the world you won’t believe a word of that will you.
That was your night sky for the week ending on Al Qaeda’s 21st birthday.