Skywatching Archives

August 11, 2011December 24, 2015 by VirtualAstro

How To Enjoy The 2011 Perseid Meteor Shower

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It’s time for the Perseid Meteor Shower and you want to bag some meteors (shooting stars), but how? Maybe you just want to know where and what time to look, or perhaps you are having a Perseid party and you want everyone to have a great time.

If so, then please read on…

First, you don’t need a telescope or binoculars or any high tech equipment. You just need your own eyes and glasses if you wear them.

It’s a good idea to be away from bright lights and if possible have a red light torch or red flashlight, but most importantly try to get your eyes adapted to the dark.

Bright light will instantaneously ruin dark adaption so shining flashlights into faces is a big no-no and looking directly at the Moon isn’t going to help either. Position yourself so you don’t get the Moon in your view.

The Perseids don’t rain down out of the sky; they appear every few minutes and this year, you may only see the rarer bright ones and very bright fireballs due to the full Moon that will be up, and the glare it will unfortunately provide. But if you can get in a good position to avoid the glare, sit back and wait to see some meteors. This is totally worth the wait, but you need to be comfortable or you will give up, go indoors and not see any.

The best bet is to get a reclining garden chair or airbed or something similar to lay back and relax upon. Lots of people put those yard trampolines to very good use and use them as meteor observing platforms.

Dress warmly and cover yourself with blankets or a sleeping bag, August is a summer month, but it can get quite chilly at 1:00am and this will make you give up early too, so stay warm.

Have plenty of drinks and snacks ready so you can basically camp out and not have to keep on getting up, or doing things, because this is when you will, ironically, miss the best fireball of the evening.

Fireball Meteor — Perseid fireball. Image Credit: Pierre Martin of Arnprior, Ontario, Canada.

Where do I look and what direction?

This is the most common question I hear people ask about meteor showers and the answer is very simple.

Follow the above comfort guidelines, look up and away from the Moon and fill your gaze with the sky.

Perseid meteors originate from a fixed point in the sky called the radiant, which is in the constellation of Perseus, however meteors will appear in any part of the sky. You can trace their paths back to the radiant.

After midnight, look towards the East/Northeast part of the your sky to find Perseus. To find it look for the easily identifiable constellation Cassiopeia, the big “W” in sky! Perseus is just below Cassiopeia.

You can draw, take pictures and even video the Perseids, but the simplest and most enjoyable thing is to lay back, relax and be patient and you will be rewarded with a great a view.

The best times to look will be in the dark pre-dawn sky on August 11, 12 and 13, 2011.

You can also follow along with Universe Today and Meteorwatch.org with #meteorwatch on twitter. Ask questions, see what others are seeing, share your experiences and images using the hashtag #meteorwatch

Most of all, enjoy your Perseid experience and have fun!

August 11, 2011December 24, 2015 by VirtualAstro

The Perseids: Why is There a Meteor Shower?

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Every year from late July to mid-August, the Earth encounters a trail of debris left behind from the tail of a comet named Swift-Tuttle. This isn’t the only trail of debris the Earth encounters throughout the year, but it might be one of the most notorious as it is responsible for the annual Perseid meteor shower, one of the best and well-known yearly meteor showers.

Comet Swift-Tuttle is a very long way away from us right now, but when it last visited this part of the Solar system, it left behind a stream of debris made up of particles of dust and rock from the comet’s tail.

Earth encounters this debris field for a few weeks, reaching the densest part on the 11th to 13th August.

The tiny specs of dust and rock collide with the Earth’s atmosphere, entering at speeds ranging from 11 km/sec (25,000 mph), to 72 km/sec (160,000 mph). They are instantly vaporised, emitting bright streaks of light. These tiny particles are referred to as meteors or for the more romantic, shooting stars.

The reason the meteor shower is called the Perseid, is because the point of the sky or radiant where the meteors appear to originate from is in the constellation of Perseus, hence Perseid.

When the Perseid meteor shower reaches its peak, up to 100 meteors an hour can be seen under ideal dark sky conditions, but in 2011 this will be greatly reduced due to a full Moon at this time. Many of the fainter meteors (shooting stars) will be lost to the glare of the Moon, but do not despair as some Perseids are bright fireballs made from larger pieces of debris, that can be golf ball size or larger.

These amazingly bright meteors can last for a few seconds and can be the brightest thing in the sky. They are very dramatic and beautiful, and seeing one can be the highlight of your Perseid observing experience.

So while expectations may be low for the Perseids this year, keep an eye out for the bright ones and the fireballs. You will not be disappointed, even if you only see one!

Join in on twitter with a worldwide event with Universe Today and Meteorwatch.org just follow along using the hashtag #meteorwatch ask questions, post images, enjoy and share your Perseid Meteor Shower experience.

August 8, 2011April 26, 2016 by Jason Major

A Noctilucent Masterpiece

Noctilucent clouds over Reykjavíc. © Örvar Atli Þorgeirsson

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Night-shining “noctilucent” clouds create a magical glow in the night skies over Reykjavíc, Iceland in this beautiful photo by Örvar Atli Þorgeirsson, taken on August 6. In the foreground is “The Sun Voyager” (Sólfar), an iconic steel sculpture located on the city waterfront representing a Viking ship.

Örvar did not set out to photograph this rare atmospheric phenomenon but had instead intended to shoot aurora triggered by recent solar outbursts.

“The forecast on the 6th of August was predicting extreme aurora activity,” Örvar says in his Flickr description. “Even though it was very early August and the night would not get fully dark I went out as the aurora can be seen in deep twilight conditions. I saw the aurora for 1 – 2 minutes that night. I did not get a good picture of it though. Instead we witnessed this even rarer phenomenon called noctilucent clouds.”

Noctilucent clouds are extremely high-level clouds made located in the mesosphere, around 76 to 85 kilometers (47 to 53 miles) high… nearly at the very edge of space. (Most commercial airplanes fly between 6 and 7 miles high.) They are high enough to reflect sunlight coming from beyond the horizon long after night has fallen over the land below. They usually appear as a wispy web of blue, white, purple and orange tendrils stretched across the sky.

“These clouds where extremely beautiful to look at and reminded me of the aurora but where much more stationary and had this beautiful blue color.”

– Örvar Atli Þorgeirsson

Noctilucent clouds are mainly visible at latitudes between 50º – 70º north and south during the months of June and July. This means Reykjavíc, located right in the middle, can get great views. (Of course it helps to have a talented photographer like Örvar to capture them so nicely!)

Oddly enough noctilucent clouds are a relatively recent phenomenon, only having been recorded for about 120 years. They have been connected with space shuttle passages through the upper atmosphere, and it’s even been suggested that they may be associated with the 1908 Tunguska impact.

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Jason Major is a graphic designer, photo enthusiast and space blogger. Visit his website Lights in the Dark and follow him on Twitter @JPMajor or on Facebook for the most up-to-date astronomy news and images!

July 24, 2011December 24, 2015 by Tammy Plotner

Now Playing At The Sky Cinema… The Moon, Mars and Aldebaran

Illustration Courtesy of McDonald Observatory

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Be on morning alert from July 26 through July 28 as the Moon, Mars and Aldebaran put on a delightful sky show that doesn’t require any special equipment – just cooperative weather! While this motion picture doesn’t have any sound, what it will have is color to delight the eye.

When it comes to viewing the night sky, most people don’t perceive much color. Things mostly appear black and white – with a little gray on the Moon thrown in for good measure. With experience, most skywatchers easily pick out blue stars and faded green in nebula, but what really gets our hearts ticking is red. And very few stars show that ruddy hue to unaided vision as well as the eye of Taurus the Bull – Aldebaran.

On the morning of July 26th, about an hour before dawn, the waning crescent Moon will be very close to Alpha Tauri and the contrast will make for a spectacular showing. The following morning, it will hover just above Mars and slide into position just below on July 27th. Take the time to really look at what you’re seeing. Of the three principle players, the only one that generates its own light is Aldebaran… the rest are products of reflection. While the star’s russet tone comes from being a cool giant, Mars’ color comes from iron oxide. Not only is the Moon reflecting back sunlight, but you’ll also see the DaVinci effect where the “dark side” is gently illuminated as well.

Don’t be surprised if folks you know ask you what’s going on. Close conjunctions such as this excites the eye! Why? When it comes to our eyes, almost every photoreceptor has one ganglion cell receiving data in the fovea. That means there’s almost no data loss and the absence of blood vessels in the area means almost no loss of light either. There is direct passage to our receptors – an amazing 50% of the visual cortex in the brain! Since the fovea doesn’t have rods, it isn’t sensitive to dim lights. That’s another reason why the conjunctions are more attractive than the surrounding starfields. Astronomers know a lot about the fovea for a good reason: it’s why we learn to use averted vision.

But don’t avert your vision when it comes to enjoying this morning show!

Original News Source: McDonald Observatory StarDate News.

June 14, 2011December 24, 2015 by VirtualAstro

Why Can We See Multiple ISS Passes Right Now?

Four ISS passes over the UK last night. Credit: Mark Humpage

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Last night in the UK, US and Europe, we were spoiled with multiple and bright ISS passes. Not just one or two, but up to six passes were able to be viewed throughout the evening in some locations.

This is quite rare as normally we get only one or maybe two visible passes in the evening or morning.

So why are we getting as many as four to six passes per night?

The ISS did receive an orbital boost and its altitude increased by around 20 kilometers. The orbital height of the ISS has an effect on how many visible passes there are at present in the Northern hemisphere. Another reason is because of the time of year.

We are only a week or so away from the Summer Solstice, the time of year when the Northern hemisphere receives the most hours of sunlight. Naturally this means we only have a few hours of darkness and the further North you go, the shorter the nights are and in some locations this time of year, it doesn’t ever get truly dark.

So why does this affect the ISS?

Basically the ISS visible passes have increased due to the station being illuminated much more by the Sun as there are more hours of sunlight right now, but the effect will wear off when we pass through Summer solstice and the nights get longer again.

Take advantage of this rare time and go outside and enjoy the ISS as much as you can in this series of visible passes.

Need to know how and when you can see the ISS? NASA has a Skywatch page where you can find your specific city to look for satellite sighting info.

Spaceweather.com, has a Satellite Tracker Tool. Just put in your zip code (good for the US and Canada) to find out what satellites will be flying over your house.

Heaven’s Above also has a city search, but also you can input your exact latitude and longitude for exact sighting information, helpful if you live out in the country.

May 27, 2011December 24, 2015 by VirtualAstro

Beginner’s Guide to Astronomy – Refractor Telescopes

If you ask someone to describe or draw a telescope, nine times out of ten it will be a refractor.

The refractor telescope is quite possibly the most common or easily recognized telescope. It is a very simple design, which has been around for hundreds of years.

The history of the refractor is that it was first invented in the Netherlands in 1608, and is credited to 3 individuals; Hans Lippershey, Zacharias Janssen – spectacle-makers and Jacob Metius.

In 1609 Galileo Galilei heard about the refracting telescope and made his own design, publically announcing his invention and further developing it through extensive experimentation. Galileo’s friend Johannes Kepler further experimented with the design, introducing convex lenses at both ends, improving the operation of the telescope.

Many advances were made and the refracting telescope became the primary instrument for astronomical observations, but there was one problem; they were huge and some were many tens of feet long!

But now, after more than 400 years and — luckily — through advances in know-how and technology, the refractor has become much more powerful and compact than some of the behemoths in the early days.

Refractors or refracting telescopes employ a simple optical system comprising of a hollow tube with a large primary or “objective lens” at one end, which refracts light collected by the objective lens and bends light rays to make them converge at a focal point.

Light waves which enter at an angle converge on the focal plane. It is the combination of both which form an image that is further refracted and magnified by a secondary lens which is actually the eyepiece. Different eyepieces give different magnifications.

The larger the size of the objective or primary lens = more light gathered. So a 6 inch refractor gathers more light than a 2 inch one. This means more detail can be seen.

There are two main types of refractor telescopes: “Chromatic” – entry level and upwards with 2 lens elements and “Apochromatic” – premium, advanced and expert level telescopes with 3 or more very high quality lens elements with exotic mixes of materials.

Chromatic refractor telescopes are particularly good for observing bright objects such as the moon, planets and resolving things like double stars, but many astronomers who image deep sky and other objects use very high quality apochromatic refractors, due to their superior optics.

Refractor telescopes are very low maintenance due to being a sealed system and it is a simple case of setup and enjoy, without the fiddling lengthy setup times you may get with other telescopes.

Refractors give clean and crisp views due to the sealed nature, unlike other telescopes like Newtonians which are subject to cooling and air turbulence issues.

Due to their small size they are very portable and can also be used for terrestrial observations the same as binoculars, which are basically two refractors bolted together.

May 24, 2011December 24, 2015 by VirtualAstro

Coming Soon – Night Shining Noctilucent Clouds

Noctilucent Cloud Display Credit: Adrian West

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Soon you may see an eerie spectacle on clear summer nights if you are located at latitudes between 50° and 70° north and south of the equator: Noctilucent Clouds.

These ghostly apparitions are a delight to see and are quite rare. It is incredibly difficult to predict exactly when they will appear, but we do know they should begin to appear soon.

The season for Noctilucent Clouds (Noctilucent = Latin for “Night Shining”) starts early June and continues into late July. They are seen just after dusk, or before dawn and an apparition can last around an hour.

These mysterious clouds, with their bizarre tenuous wispy shapes reminiscent of ripples in sand or the changing surface of a pool of water, spread like a glowing web across the northern sky. Colours can range from brilliant whites, with tinges of blue, pink and orange.

Formed by tiny ice crystals, they are the highest clouds in the Earth’s atmosphere, located in the mesosphere at altitudes of around 76 to 85 kilometers (47 to 53 miles) almost at the edge of space.

They are normally too faint to be seen, and are visible only when illuminated by sunlight from below the horizon, while the lower layers of the atmosphere are in the Earth’s shadow. Noctilucent clouds are not fully understood and are a recently discovered meteorological phenomenon, only being recorded for about 120 years.

Noctilucent clouds can only form under very restrictive conditions, and their occurrence can be used as a guide to changes in the upper atmosphere. Since their relatively recent classification, the occurrence of noctilucent clouds appears to be increasing in frequency, brightness and extent.

There is evidence that the relatively recent appearance of noctilucent clouds and their gradual increase, may be linked to climate change. Another recent theory is that some of these bright displays come from particulates and water vapour in the atmosphere left over from Space Shuttle launches.

How can you see them? Over the next couple of months look north during dusk and dawn and try and spot this mysterious and elusive phenomenon. They are best seen when the sun is between 6 and 16 degrees below the horizon, and seem to occur more frequently in the Northern hemisphere than the Southern.

Good luck!

Noctilucent clouds over Blair, Nebraska, USA. Credit: Mike Hollingshead

May 13, 2011December 24, 2015 by Tammy Plotner

Weekend Observing Challenges – May 13-15, 2011

Greetings, fellow SkyWatchers!

I’m sure everyone has been enjoying following the morning planet show, but are you ready for something else? If you’ve got a telescope, then we’ve got some projects for you. While it’s definitely going to be a “moon light” weekend, that doesn’t mean that you can’t have fun! Let’s take a look at what the night has to offer…

On Friday and Saturday evening, the most prominent lunar feature will be the ancient and graceful Gassendi. Its bright ring stands on the north shore of Mare Humorum – an area about the size of the state of Arkansas. Around 113 km in diameter and 2012 meters deep, you will see a triple mountain peak in its center and the south wall eroded by lava flows. Gassendi offers a wealth of details to telescopic observers on its ridge and rille covered floor.

When you have finished with your lunar observations, let’s travel on to a fascinating double star. A little less than a handspan south of the last star in the handle of the “Big Dipper”, you will see a fairly bright star that is on the edge of unaided eye detection thanks to tonight’s gibbous Moon. Aim your telescopes or steady binoculars there for a real treat! Alpha Canum is more commonly known as Cor Caroli – or the “heart of Charles” – and is a true jewel easily split by the most modest of instruments. Although some observers may not be able to distinguish a color difference between the magnitude 2.8 and 5.6 companions, it has been my experience that most will see a faded blue primary (a magnetic spectrum variable) and pale orange secondary on this 120 light year distant pair. If you are equatorially aligned, turn off the drive and wait for 150 seconds. Widely separated Struve 1702 will be coming into view…

On Sunday night your lunar challenge will be a challenging one – worthy of the larger scope. Start by identifying past study craters, Hansteen and Billy. Due west of Hansteen you will find a small crater near the terminator known as Sirsalis. It will appear as a small, dark ellipse with a bright west wall with its twin, Sirsalis B on the edge. The feature you will be looking for is the Sirsalis Rille – the longest presently known. Stretching northeast of Sirsalis and extending for 459 kilometers south to the bright rays of Byrgius, this major “crack” in the lunar surface will show several branches – like a long dry river bed.

Tonight let’s go from one navigational extreme to another as viewers in the northern hemisphere try their hand at Polaris. As guide star for north, Polaris is also a wonderful double with an easily resolved, faint blue companion for the mid-sized telescope. But what about the south? Viewers in the southern hemisphere can never see Polaris – is there a matching star for the south? The answer is yes – Sigma Octantis – but at magnitude 5, it doesn’t make a very good unaided eye guide. Ancient navigators found better success with the constellation of Crux, better known as the “Southern Cross”. While Crux has many wonderful double stars, if southern hemispere viewers would like to see a star very similar to Polaris, then try your luck with Lambda Centauris. The magnitude difference between components and separation are about the same.

Good luck and clear skies!

Many thanks to Peter Lloyd for setting the Moon phase stage and Damien Peach for his incredible lunar photos!

April 29, 2011April 26, 2016 by VirtualAstro

Last & Best Chances to See NanoSail-D

Nanosail-D Pass Credit: Vesa Vauhkonen, Spaceweather.com

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Over the next few weeks, skywatchers will have excellent viewing opportunities for the NanoSail-D solar sail.

The satellite is coming to the end of its 95-day mission to test the viability of de-orbiting decommissioned satellites or space debris. NanoSail-D is now de-orbiting and slowly losing altitude in the Earths thin upper atmosphere.

As the satellite descends, viewing opportunities will improve.

To see NanoSail-D pass over, you will need to know exactly when it will be visible from your location. To do this, go to Heavens-above.com or Spaceweather.com where star charts with times and pass details will be displayed after you enter your observing site.

Once you know the time and location in the sky of the pass of the satellite, make sure you are able to get a good view of the part of the sky where the satellite due to appear. Give yourself plenty of time, go outside and get ready. I always set a 30 second reminder on my watch or cell phone, so I don’t have to fumble around or guess the time.

To enjoy the NanoSail-D passes:

• Make sure you know the right place in the sky and the time of the pass, by checking on the web.
• Make sure you will be able to get a clear view of it from your viewing location.
• Set an alarm or get ready for the pass as it only lasts a few seconds.
• NASA expects NanoSail-D to stay in orbit through May 2011.
• If you are an astrophotographer, don’t forget, NASA and SpaceWeather.com are having an imaging contest of NanoSail-D. Find out more here.
• Most of all, get your friends and family outside with you to watch NanoSail-D and enjoy!

Artist concept of Nanosail-D in Earth orbit. Credit: NASA

April 26, 2011December 24, 2015 by VirtualAstro

Shuttle Endeavour Will Be Visible Over UK Just After Final Launch

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On April 29th, 2011, the space shuttle Endeavour is scheduled to blast off for the last time, delivering the Alpha Magnetic Spectrometer and an ExPRESS Logistics Carrier to the International Space Station.

If you live in the UK you can watch the launch live on NASA TV and a number of other sites on the internet, but that’s not all you can do! You may be able to watch it fly over the UK with your very own eyes about 20 minutes later!

Yes! You can watch the Shuttle fly over the UK roughly 20 minutes after launch (launch time is currently set for 3:47 p.m. EDT – 8:47 p.m. UK Time) if the timing is right and skies are clear. It will be accompanied by its bright orange external fuel tank as it sails across the sky.

I was lucky to see and actually film this in August 2009 with the launch of STS-128 Space Shuttle Discovery.

How to see it? Go outside roughly 15 – 20 minutes after launch and you could see two bright objects similar to what the ISS looks like when it passes over, moving at roughly the same speed. These bright objects in parallel to each other will follow a similar track in the sky to what the ISS does, but it will be the Shuttle Endeavour and its separated external fuel tank!

Hope for clear skies and that the launch isn’t delayed, as this may be our last chance ever of seeing a space shuttle fly over the UK just after launch.

Checkout NASA’s listing of sighting opportunities for your area.

Good luck to the crew of the shuttle and to everyone trying to spot it in the sky on Friday!