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Whitby’s Eye on the Night Sky

People stand and look at the moon one day ahead of the Supermoon phenomenon from a bridge over 42nd St. in the Manhattan borough of New York July 11, 2014. Occurring when a full moon or new moon coincides with the closest approach the moon makes to the Earth, the Supermoon results in a larger-than-usual appearance of the lunar disk.         REUTERS/Carlo Allegri (UNITED STATES - Tags: SOCIETY CITYSCAPE) - RTR3Y8LT

People stand and look at the moon one day ahead of the Supermoon phenomenon from a bridge over 42nd St. in the Manhattan borough of New York July 11, 2014. Occurring when a full moon or new moon coincides with the closest approach the moon makes to the Earth, the Supermoon results in a larger-than-usual appearance of the lunar disk. REUTERS/Carlo Allegri (UNITED STATES - Tags: SOCIETY CITYSCAPE) - RTR3Y8LT

The Full Moon on Sunday (August 10) should look particularly impressive as it is a so-called Mega Moon event.

These occur when moonrise coincides with a lunar perigee; when the Moon is closest to Earth in its orbit.

On Sunday, this occurs just an hour before moonrise over the UK when the Moon will be 356,896km away (around 221,000 miles in old money)

Mega Moons can be 30% brighter and 14% larger than a normal moon, so it should be quite a sight as it rises around 8.15pm.

Of course the moon always appears to be large when in proximity to the horizon, an effect known as the Ponzo illusion –a trick of the mind. Hopefully the weather will allow us to test this. Fingers crossed.

Planetary Skylights

Mars and Saturn are visible in the evening sky, with Mars drawing ever closer to Saturn as we head through August. Look for them low in the SW later in August, they are closest around Aug 27, the ruddy hue of Mars contrasting nicely with pearly white Saturn.

Telescopically the pair appear very different, Mars; very small and exhibiting a hint of a phase, but little else, whilst Saturn has the glorious ring system, visible through even a small instrument.

The moon lies near Mars on Aug 2nd and Saturn on the 4th. Then on Aug 31st the crescent moon is again just under Saturn.

The planetary highlight of the month is however to be found in the dawn sky, when Venus and a returning Jupiter have an extremely close conjunction, almost touching to the naked eye.

You will need to be up early on Aug 18, look to the ENE around 4.45am, Venus will be the brighter of the two, just above Jupiter. View with binoculars or a telescope on very low magnification and you should also spot two of Jupiter’s moons Io and Europa, as well as the lovely open star cluster known as the Beehive.

If skies are forecast clear for that morning, set the alarm! A few days later a waning crescent moon passes both planets.

Next Moon Phases - Full 10th; Last Qtr 17th;New 26th.

The Glorious Twelfth – The Perseid Meteor Shower

When amateur astronomers refer to the ‘glorious 12th’ they are not contemplating shooting grouse, pheasant or any other game bird, they are however anticipating shooting stars!

The ‘shooting stars’ in question are the Perseids, one of the more reliable meteor showers and undoubtedly the most widely observed given that the shower occurs during the summer months. Perseids are so called because their radiant; the location in the sky from which the meteors appear to emanate, lies within the constellation of Perseus.

In some regions of the world the Perseids are also known as “The Tears of St Lawrence”, because the feast day of that saint falls on Aug 10th, just two days before the meteor peak.

Laurentius, a Christian deacon, was said to have been martyred by being roasted alive on an iron outdoor stove by the Romans in 258 AD. It was in the midst of this torture that Laurentius cried out: “I am already roasted on one side and if thou would’st have me well cooked it is time to turn me on the other side.

Perseids are associated with debris from the periodic comet Swift Tuttle, deposited over many thousands of years. Each August, Earth ploughs through this giving rise to the Perseids. This ‘debris’ is typically about the size as instant coffee granules, with the occasional pea or marble sized fragment.

Typically these fragments ‘burn up’ at an altitude of around 60 miles having reached speeds of 39 - 45 miles per second. The most rewarding regions of the sky for spotting Perseids are high to the south-within the ‘Summer Triangle’ also around Ursa Major and the Square of Pegasus

Under ideal conditions the Perseids are one of the year’s more prolific showers,, however the peak of the shower this year coincides with an almost full moon, drowning out many of the fainter meteors.

Instead of the usual 30-40 per hour actually witnessed, peak rates observed this year (11pm on 11th until 3am on the 12th), will be a third of this. However there is still every chance of a few brilliant shooting stars lighting up the sky, so it’s always worth keeping an eye open, if not two.

Of course in Whitby matters are further complicated by the fact the 11th is Regatta Monday night, plenty of artificial fireworks, hopefully followed by some of Mother Nature’s?

The Celestial Ocean – August Skies

It’s been a while since we last undertook a general ‘celestial ramble, but now evenings are noticeably drawing in once again and observers have a little more time to explore and appreciate the summer night sky under fully darkened skies.

Brighter stars begin to emerge around 9pm and by 10pm the majority of summer constellations are visible. Six stars in particular catch the eye, these are:- Arcturus, Vega, Deneb, Altair, Capella and Antares.

Arcturus, the most brilliant of our summer visitors is located across in the W in the constellation of Bootes - the Herdsman. Once fully dark, note the delicate starry circlet of Corona Borealis situated to the upper left of Arcturus.

Higher up in the NW sits the familiar saucepan outline of the ‘Plough’, part of Ursa Major. Use the pointer stars of the Plough to locate our present pole star;- Polaris in Ursa Minor - due north and high up.

Do not confuse brilliant Capella, in Auriga found low above the N horizon during late summer for the North Star. Swing back around to the SW, an aspect chiefly occupied by two large and rather ill defined groups, Hercules and Ophuichus.

The figure of Hercules sprawls across the higher regions of the SW left of Corona.

It is best identified by the ‘keystone’ asterism. Below Hercules the fainter outline of Ophuichus;- the serpent bearer, extends down towards the SW.

Just above the horizon in this direction note bright orange hued Antares in Scorpius, which is sadly from our point of view only partially rises over Britain. The same can be said of the next constellation; Sagittarius which follows the Scorpion across the S horizon.

Both groups are very rich in deep sky objects.

Much of the SE aspect is also occupied by zodiac constellations, including Capricornus - the Sea Goat (SE) Aquarius- the Water Bearer (ESE) and Pisces - the Fish (E). Dark skies are needed to trace these groups as they are all quite faint. High overhead to the south and extending down to the SSE, the constellations of the ‘summer triangle’; -, Lyra, Cygnus and Aquila, dominate.

Almost equal in brightness with Arcturus, steely blue Vega sits atop the small geometric pattern of Lyra

Deneb sits at the tail of Cygnus – sometimes referred to as the Northern Cross, whilst pearly Altair in the eagle Aquila shines midway up in the SSE.

A short distance above Altair note the small arrow shaped group of Sagitta together with the close-knit group of Delphinus situated to its left. Delphinus is one pattern that with a little imagination does resemble the outline of a dolphin leaping out of water.

Delphinus was sometimes referred to as ‘Jobs coffin’ although the origin of this is not known.

Climbing up from the NNE horizon the great hero Perseus stands proud, whilst above his shoulder in the NE Queen Cassiopeia - the familiar “W” pattern, sits on her throne.

The eastern aspect of the sky is dominated by just a few constellations, in particular the winged horse Pegasus. This group is best identified by “the great square”, an arrangement of four reasonably prominent stars enclosing a large area of sky seemingly devoid of stars.

Between Pegasus and Perseus stretches the chained princess Andromeda, daughter of Cassiopeia. Situated within the borders of Andromeda, our “big sister” galaxy can be glimpsed on clear moonless nights, the most remote object visible to the naked eye - a staggering 2.5 million light years away.

As usual WDAS will be hosting numerous star party events throughout August. Please refer to the Regatta programme for our Regatta star parties. Further scheduled star parties on the West Cliff – near Cpt Cook’s monument, occur on the16th, 22nd 23rd and 24th all from around 9pm, weatherpermitting.

For more information email Mark at spanton33@talktalk.net, call (01947) 605516 or visit

www.whitby-astronomers.com

 

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