Sky News for August 2017

What to look for in the sky this month.

The solar system, showing the relative position of the planets on 13th August, generated with Pocket Universe.

The news this month is dominated by the total Solar Eclipse visible from the United States, which takes place on the morning of August 21st. The latest version of Pocket Universe has an eclipse tracker built-in, so make sure you’re near the center of the shadow to see the total eclipse. The Moon will pass in front of the Sun, blocking out all light, and creating an amazing effect that has to be experienced.

If you are not in the central shadow, you’ll see a partial eclipse — the Moon covers the Sun, but doesn’t blot it out completely. Although hard to see, because the Sun is still very bright, the Sun will appear like a crescent. If you don’t have high-quality solar filters DO NOT STARE AT THE SUN. Instead, project the light on the ground.

NEVER EVER LOOK AT THE SUN WITH BINOCULARS OR A TELESCOPE without using the correct filters. Do not blind yourself on August 21st!

Planets

  • Mercury soon follows the Sun under the evening horizon, and then it’s gone. If using a telescope, please be extra careful. Although you’ll see Mercury as a crescent, don’t risk looking at the Sun.
  • Venus is a morning start — extremely bright, rising well before dawn.
  • Mars is on the other side of the Sun from Earth and so is lost from observers.
  • Jupiter and Saturn are in a wonderful locations. Get out that telescope, or even binoculars, and find these enormous planets in the South/Western sky. Jupiter’s moons, and Saturn’s rings are both a treat.
  • Uranus and Neptune are faint morning objects this month.

The Moon

  • Full Moon — August 7th
  • Last Quarter — August 14th
  • New Moon — August 21st (day of the Eclipse of course)
  • First Quarter — August 29th

Partial lunar eclipse visible from Europe and the Pacific — August 7th

Meteor Showers

The Perseids — perhaps one the strongest showers of the year — peak on 12th August this year. Unfortunately, the Moon could be bright enough to make all but the best meteors invisible this year, but it’s always worth a look!

The Sky in August

Pegasus is an easy constellation to miss, because it is so huge it can take a moment to get the sense of scale right in your mind. It is also disappointingly nothing like a winged horse, so you need to switch your imagination to overdrive.

However, the dominant feature is easy to spot once you’ve seen it the first time: the “great square” is made up of four bright stars. There isn’t much inside the square, however, outside it you’ll find the brightest star in the constellation, called Enif. With a telescope, you’ll be able to spot that it is actually a double star — you should be able to see the smaller blue star (with a larger telescope still, you will see a third, even fainter star!). Close to Enif is M15, a pretty star cluster worth examining with a telescope.

Aquarius is lower in the sky, and again, it’s a stretch to see anyone carrying a jug of water in the pattern of stars. However, Aquarius has some very interesting features. Start with M2, which is a globular cluster of stars. Then look for the Saturn Nebula, very close to M73 and M72 — two more globular clusters. If the night is dark and clear, look for the large, but faint and diffuse, Helix Nebula, towards the bottom of the constellation.

Equuleus and Delphinus are two small constellations that will test your observation skills. Perhaps the most interesting thing about Delphinus are the names of its two brightest stars: Sualocin and Rotanev — they are the name of an astronomer spelt backwards.

General Sky Watching

At first glance, the night sky is a dome sprinkled with stars — and the darker the night, and the clearer the skies, the more stars you will see. However, the more you learn about the sky, the more you realize there is to see. Not all the lights you see are stars — some are actually planets (lumps of rock and gas that make up our Solar System), some are galaxies — themselves containing millions of stars — some are immense clouds of interstellar gas, some are clusters of stars..

Although the stars have positions that appear fixed with respect to each other, the planets, the Sun and the Moon appear to move. You might have noticed that the Moon is in a different place in the sky at the same time every night — in fact, it rises later and later every day. You’ve no doubt noticed the Moon changes its appearance: the shape changes from day to day as the angle between the Sun, the Moon and ourselves changes, altering the illumination falling on the Moon’s surface.

In other words, the night sky is a surprisingly dynamic place. Things move, and evolve, not only on a human scale of a few days or hours, but over millions of years. Nothing is still, the Universe is alive!

There are many books and magazines available which will give you suggestions for things to look for in the night sky. Here are some of my own suggestions for what to look for on a clear night.

Naked Eye Observing

You can see thousands of stars with your naked eye, and they all appear as twinkling points of light. In fact, even with a large telescope, stars still appears as mere points: although huge, they are incredibly far away. It takes the very light you see years and years to travel the distance from the star’s surface to your eye.

The patterns in the stars which we call “constellations” are merely random pictures that human beings have created. There’s nothing special about them, other than an agreement on the pattern, and as they provides a quick and convenient way of identifying specific portions of the sky, their use has continued from ancient times.

You should remember that merely by sharing the same constellation says nothing about where are star is actually located in space, other than it appears to be near each other. The stars could actually be thousands of times further away from us, and merely “line up” because of our view point.

Still, learning the names and shapes of the Constellations is important, and a good way to spend an evening. Take Pocket Universe out, hold it up, and turn of and off the Constellation outlines to get an idea for the sense of scale involved.

If the night is clear, you’ll start to ascertain that some stars are a different color from others; Vega is a brilliant blue/white for example — compare this with Betelgeuse!

The planets will also appear as points of light with the naked eye, but it’s still possible to see Mars, Venus, Jupiter and Saturn very easily. It’s said the light from the planets doesn’t twinkle as much as star light, but I’ve never noticed this myself! If you watch out for the planets from night to night, you’ll see their position has changed slightly with respect to the stars around them. The planets are much, much closer than stars, and here on Earth we’re part of the same solar system, so we all spin around the Sun together.

On a very clear night, away from city lights, you’ll see The Milky Way. This is an edge-on view of the galaxy in which our Sun is a part. Almost every star you see in the sky is part of The Milky Way: these are our interstellar neighbors.

If you want to see another galaxy, track down Messier object M31 — the Andromeda Galaxy. The Andromeda Galaxy will look like a fuzzy patch of light, best seen just out of the corner of your eye. This galaxy is so far away, it takes 2 million years for the light from its stars to reach us. Sadly in the Northern Hemisphere, M31 sets too early to see at this time of year.

To see something a little closer to home, find M45 The Pleides. This is a cluster or grouping of stars, merely 440 light years away (the light you see tonight, set off in 1571AD). You might know them as The Seven Sisters, as those with good eye-sight can count seven stars in the group. Unfortunately in Summer, the Pleides also don’t rise far above the horizon until just before dawn in the Northern Hemisphere. Let’s find something a little easier to spot.

Binoculars

Saturn! Look at Saturn! Once you’ve spotted the rings (if your binoculars are half-way decent), start looking for other planets. You should be able to see Uranus and Neptune if you follow Pocket Universe’s directions.Get up early and look for Jupiter: with large binoculars you will be able to see the four brightest moons which orbit it. Mars will still only look like a speck, but you might be able to pick out a ‘phase’ of Mercury i.e. it won’t look perfectly round. And then of course, we get to the “deep sky objects”, such as the Messier objects.

Telescope

Saturn again, obviously! With a telescope, you can observe Jupiter’s moons of course, but also pick out details on Jupiter’s surface. Jupiter is surrounded by huge ‘bands’ of gasses, and you should be able to make out two thick darker ‘belts’ with even a smaller telescope. Mars is not in the best location for observation at present, but with a good telescope you should be able to see a white smudge at one pole — this is the ice-cap.

ISS

Orbiting the Earth right now, at a height of approximately 350Km and traveling at almost 30,000 kph — that’s 200 miles, and 18,000 mph for you non-scientific unit folks) is the International Space Station. It’s the world’s only permanently manned outpost in space, and although it’s huge, it’s still under construction. It’s so big you can actually see it from the surface Earth, as long it’s flying overhead and is reflecting sunlight in your direction.

Pocket Universe allows you to track the position of the ISS as it passes over the Earth. From the new ISS view, you can see what country the station is currently flying over, and if there are any sighting opportunities for your region.

If there is a suggested observation time, you’re in luck. Spotting the ISS is easy and fun — close to the suggested time, find a spot with a clear view of the horizon. Times which are just after sunset work best. You should see a very bright ‘star’ drift across the sky. It will finish its pass in about 2 or 3 minutes, and it might not get very high in the sky. At times, the ISS will be in Earth’s shadow, and may not be visible — so just after the sun has set, but when the ISS is still reflecting sunlight will give the brightest target. You can also watch for the ISS in the Virtual Sky mode (if you turn on ISS Updates from the Settings page). A little satellite will be drawn in the approximate position of the ISS to help you find it. But be quick — the ISS zooms past pretty quickly! If you have binoculars or you are good at moving your telescope quickly, you might be able to make out the shape of the station. Amateur astronomers have even managed to photograph astronauts taking a space walk!

This sky report brought to you by Pocket Universe, the astronomy application for the iPhone and iPad. Hold it up to the sky, and learn what you are looking at!

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