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Saturday, April 19, 2014

 

Carnival of Space #350 is Here!

Carnival of Space #350 is now up at CosmoQuest. There's the first true Earth-sized world in a habitable zone around another star, planet formation, a new Moon for Saturn, sobering statistics on asteroid impacts and lots, lots more. Take a spin on over and have a read.

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Aurora Watch issued for April 20-21 (Easter Sunday-Monday)

The Australian IPS has issued both a geomagnetic alert and an Aurora Watch for April 20-21. Tasmania, Southern New Zealand, and possibly southern Victoria, southern WA and the North Island should be on the lookout for Aurora from around astronomical twilight (and hour and a half after sunset) on the 20th until twilight on the morning of the 21st. At the moment it is most likely that any serious geomagnetic storm, and hence aurora, will occur after midnight in the early hours of the morning of the 21st, but the solar wind streams might arrive early, of the combination of the two CME events may ramp up activity early.

However, the waning but still bright moon rises around 22:00 on the 20th and will interfere with seeing any aurora (although we have some recent good aurora seen under full Moonlight), and dark sky sites have the best chance of seeing anything.
SUBJ: IPS AURORA WATCH ISSUED AT 0001 UT ON 19 Apr 2014 BY IPS RADIO AND SPACE SERVICES FROM THE AUSTRALIAN SPACE FORECAST CENTRE Two Coronal Mass Ejections, the first slow and weak but the second faster and stronger are expected to impact the Earth. The first is expected sometime after midday on the 20th of April AEST, with the second expected around midnight on the 20th. Note that arrival times are generally uncertain by +/- 6 hours or so. The first event on its one would not warrant an aurora watch however the second would in its own right and the combination of the two may amplify the effects of the second. Auroral activity visible from Tasmania and possibly further north in Australia is expected from this event, should the arrival time coincide with local nighttime as anticipated. Aurora alerts will follow should favourable space weather activity eventuate.

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Thursday, April 17, 2014

 

I missed the Occultation of Lambda Aquarii by Venus, but Tom Harradine didn't

I jinxed myself by not getting my travelling box of lenses and guff out of the cupboard and putting it on the bench the night before. But hey, I said, I'm not driving, so I have plenty of time to open the cupboard and walk to the back yard. Pah! So I missed wake up time (heck I missed my normal work wakeup time) and missed the occultation of lambda Aquarii by Venus.

But Tom Harradine didn't. Here is his shot of the star emerging from behind Venus, and a nice video of the star emerging.

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Partial Solar Eclipse, April 29 2014

Partial Eclipse as seen from Brisbane near maximum eclipse, 5:00 pm AEST. Simulated in Celestia. Click to embiggenPartial Eclipse as seen from Sydney near maximum eclipse, 4:55 pm AEST. Simulated in Celestia. Click to embiggen
Partial Eclipse as seen from Melbourne near maximum eclipse, 5:00 pm AEST. Simulated in Celestia. Click to embiggenPartial Eclipse as seen from Hobart near maximum eclipse, 4:55 pm AEST. Simulated in Celestia. Click to embiggen

On the afternoon of April 29, there will be an annular Solar eclipse. In an annular eclipse the Moon does not completely cover the Sun, and the Sun forms a thin ring around the Moon at maximum eclipse depth. From Australia though, we only get to see a partial eclipse.

Viewers will see between 64% (Hobart) - 4% (Darwin) of the Sun covered by the Moon, with southern Australia favoured (the opposite of last years annular eclipse). The partial solar eclipse occurs close to sunset and in some places such as Sydney and Brisbane the Sun sets during maximum partial eclipse (see the table below). This is an excellent opportunity of get dramatic images of the "Crescent" sun setting. You will, however, need a flat, unobstructed horizon to see the eclipse at its best.

A table showing eclipse times for more Australian cities in Universal Time is here, and a map of the path is here.

Do NOT look directly at the Sun! Do not use so called filters. Over exposed film, smoked glass etc. used as filters are NOT, repeat NOT safe. Only special solar-rated viewing spectacles from astronomical suppliers should be used (for one example see here), they may cost a bit, but your eyesight is without price. Never use eyepiece filters for telescopes. These can crack at inopportune times and destroy your eyesight. At no time is it safe to view the eclipse with the unaided eye.

The easiest and cheapest way to observe this event is by making a pinhole in a stiff square of cardboard and projecting the image of the Sun onto a flat surface. You are basically making a simple pinhole camera, which will reveal the changes to the Suns outline quite satisfactorily. A card with a 1 mm hole should be projected onto a surface (eg white paper, or a white wall) about 20 cm away, a 5 mm hole should be projected onto a surface 1 to 1.5 meters away.

You need to create a reasonable sized image, so you need a fair distance between the pinhole and the surface you project the image on. This will mean the image is going to be fairly dim, so you also need some sort of sun shield to keep in image in shadow. I use the longest available postpac postal tube, with alfoil over the top (and the pinhole in the alfoil), and wide ring of stiff cardboard to ensure that the image of the sun is projected into a dark area. This link will show you several methods to make pinhole projection systems.

You can also use binocular and telescopic projection systems. This link will show you how to make safe solar viewing and telescope projection systems. Here is my step by step guide to making a binocular projection system, and a guide to aiming your binoculars or telescope when you can't actually look at the Sun. And this is the projection system I use with my refractor telescope.

Remember, do NOT look directly at the Sun, as irreparable eye damage or blindness can occur (see this video for a graphic demonstration).

City Eclipse Start Mid Eclipse Eclipse End % Sun covered
Adelaide (ACST) 3:25 pm 4:37 pm sets 5:35 pm 51
Alice Springs (ACST) 3:44 pm 4:47 pm 5:54 pm 26
Brisbane (AEST) 4:31 pm 5:17 pm sets mid eclipse 24
Cairns (AEST) 4:25 pm 5:01 pm sets 5:59 pm 10
Canberra (AEST) 4:05 pm 5:12 pm sets 5:22 pm 46
Darwin (ACST) 4:21 pm 4:55 pm 5:28 pm 4
Hobart (AEST) 3:51 pm 5:00 pm sets 5:17 pm 64
Melbourne (AEST) 3:58 pm 5:07 pm sets 5:35 pm 55
Perth (AWST) 1:17 pm 2:42 pm 3:59 pm 49
Sydney (AEST) 4:14 pm 5:15 pm sets mid eclipse 41
Townsville (AEST) 4:49 pm 5:30 pm sets 5:52 pm 10

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Wednesday, April 16, 2014

 

Don't Forget, Venus Occults Lambda Aquarii Morning April 17, 2014

The bright star Lambda Aquarii about to exit from the dark side of Venus at 4:04 AEST as seen from Brisbane. Most other Australian locations that see the occultation will see similar views, although Venus will be closer to the horizon. The insert shows the telescopic view, click to embiggen.

Don't forget that tomorrow morning at 3:59 am AEST (3:29 am ACST) Venus will occult the bright star Lambda Aquarii.

This is a rare occurrence, and the sight of the Star exiting from Venus's dark side will be quite different to a Lunar occultation due to Venus's atmosphere.

Brisbane has the best view, with Venus being higher than all other locations when it occults the star. For more details, charts and timings see my Venus occultation page.

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The Sky This Week - Thursday April 17 to Thursday April 24

The Last Quarter Moon is Tuesday April 22.  Jupiter is the brightest object in the evening sky, visible in the early evening. Mars is prominent in the late evening sky. Saturn rises higher in the evening sky, the Moon is close to Saturn on the 17th. Venus is prominent in the morning sky and occults a star on the 17th.  Mercury is lost in the twilight. The asteroids Vesta and Ceres are visible in binoculars.


The Last Quarter Moon is Tuesday April 22.  The Moon is at perigee, when it is closest to the Earth, on Wednesday April 23.

Evening sky on Saturday April 19 looking north-west as seen from Adelaide at 21:00 pm ACST in South Australia. Jupiter is above the north-western horizon. The inset shows Jupiter's Moons at this time. Io is starting to cross Jupiter's disk. Similar views will be seen elsewhere at the equivalent local time (click to embiggen).

Jupiter is in the constellation Gemini and is the brightest object in the evening sky. Jupiter was at opposition on the 6th of January, when it was brightest and closest to Earth, but will remain bright and easily observable in telescopes for in the early evening for the rest of this month.

Jupiter is highest around 17:30 pm local  time. It is high enough to begin observing telescopically when twilight ends. Jupiter sets around 10:00, so there is only a few hours for good telescopic observation now.

In the early evening it is above the north-western horizon between the bright stars Castor and Pollux, the twins of Gemini, and the bright red star Betelgeuse. Jupiter is quite easy to see as the brightest object in the entire sky, in the evening the sight of bright Jupiter sinking to the west, and bright Mars (still not as bright as Jupiter though) rising in the east is quite beautiful.

Jupiter's Moons are readily visible in binoculars.On the 19th Io transits Jupiter. around 21:00.

Mars rises around 17:10 pm local time, and is now easily seen in the evening, rising as Jupiter is setting. It is highest in the sky around 23:30. Mars was at opposition, when it is biggest and brightest, on the 9th, and is readily distinguishable as the bright red/orange object above the evening horizon. Mars is in the constellation of Virgo near the bright star Spica (see below). Mars is well worthwhile looking at in a telescope now, although you will need a decent one to see any detail.

Saturn is rising higher in the evening sky. Saturn is high enough around midnight for decent telescopic observation (see below).  Saturn is in Libra near the head of the constellation of the Scorpion. Saturn forms a triangle with the two brightest stars of Libra, its apex pointing towards the head of the Scorpion. The Moon is close to Saturn on the 17th.


Morning sky on  Thursday April 17 looking east as seen from Brisbane at 3:58 am AEST in OLD.  Venus is above the horizon and has just finished occulting the brigtht star Lambda Aquarii.. The inset shows the telescopic view of Venus at this time.  (click to embiggen).

The morning sky is quite impressive at the moment, with Mars, Saturn,  Venus and Mercury strung out across the sky.

Venus is in the morning sky, above the eastern horizon.  The brightest object in the morning sky, it is now easy to see and although it is past maximum brightness, it will dominate the morning sky for some months to come.  Venus was at its furthest distance from the Sun on the 23rd of March, and now will begin to slowly sink towards the horizon. Venus  is now a clear half-Moon shape.

On the morning of the 17th Eastern Australia sees a rare event, the occultation of a bright star by Venus. Venus covers the start Lambda Aquarii around 3:58 AEST, and uncovers it from the dark side at around 4:04 AEST. Brisbane has the best view, with Venus being higher than all other locations when it occults the star. For more details, charts and timings see my Venus occultation page.

Mercury disappears into the twilight.


Evening sky on Thursday April 17 looking east as seen from Adelaide at 21:00 pm ACST in South Australia. Mars is close to the bright star Spica. Saturn forms a triangle with the two brightest stars of Libra and is close to the Moon. The insets show the telescopic views of Saturn and Mars at this time (although you will need a good telescope to see Mars in this detail).

The asteroids Vesta and Ceres are just below Mars, and easily visible in binoculars. Similar views will be seen elsewhere at the equivalent local time (click to embiggen).

Two bright asteroids are now visible in binoculars in the evening sky. 1 Ceres and 4 Vesta. Vesta  is now bright enough to be just visible to the unaided eye in dark sky locations.Unfortunately the waxing Moon means that it will not be visible to the unaided eye this week. While Vesta is easily seen in binoculars, you will need to watch the same patch of sky in binoculars for a couple of nights to identify it by its movement. Ceres never gets brighter than magnitude 7, but is easily in the range of 10x50 binoculars after the first few days when the light of the nearly full Moon interferes. See here for a printable black and white map suitable for seeing seeing Vesta and Ceres.

There are lots of interesting things in the sky to view with a telescope. Especially with Jupiter, Mars and Venus so prominent in the sky, and Saturn coming into view.  If you don't have a telescope, now is a good time to visit one of your local astronomical societies open nights or the local planetariums.

Printable PDF maps of the Eastern sky at 10 pm AEDST, Western sky at 10 pm AEST. For further details and more information on what's up in the sky, see Southern Skywatch.

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Tuesday, April 15, 2014

 

Images from the April 15 Twilight Lunar Eclipse


I had my viewing spot all picked out for the eclipse when I got home, but unfortunately I got lost driving there. I ended up on the lookout above Mutton Bird Cove, nice stable surface on a rise with only a low line of hills between me and the rising Moon.

As the Sun set I scanned just above the hills while setting up the camera and the separate telescope camera combination (4" Newtonian reflector with 20 mm Plossl lens and Canon IXUS in infinity-infinity apposition). My mate Tony and his partner turned up and set up their cameras (serious cameras). Fortunately, they bought the one thing I didn't bring. mosquito repellent to deal with the clouds of ravenous blood suckers that had descended on me.

video

Just the I noticed the tiny sliver of Moon that had climbed above the hills, and rushed to get the scope on it (I had aimed too far to the left). I had not expected two things, how dim the eclipsed Moon would be in the horizon murk, and the degree of turbulence. The video above shows exactly how bad the turbulence was, I didn't get anything like a decent shot until the eclipse was nearly at an end.

Still even though the rising eclipsed Moon was nearly impossible to see early in the twilight, and the red of the dark part of the Moon was not as pronounced as it rose higher in the sky, it had a very eerie, ethereal quality, especially rising over the sinewy marshes of Mutton Bird cove with the pale hills beyond. The others got some great shots of the eclipsed Moon reflected in the rivulets of the cove.The growing sliver of Moon was oriented in a way no actual crescent Moon would be (facing the wrong way and almost vertically aligned in the beginning. Mats was it's companion early on, the rusty planet and the rusty chip of Moonadding to the unearthly feeling.

I had to pack up before the end (my family were wondering what had happened to me), but aside from the hordes of mosquitoes it was a unique and wonderful experience, the pale rddish chip of Moon suspended over the blue hills of one side, the flaming colours of the sunset seen through the industrial landscape on the other, it was fantastic. 

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Final Reminder, Twilight Total Lunar Eclipse, evening April 15, 2014

Eastern horizon as seen from Sydney on April 15 at 6:30 pm AEST. Totality is just ending. Click to embiggenEastern horizon as seen from Adelaide on April 15 at 6:00 pm ACST Totality is just ending. Click to embiggen

A final reminder that in the early evening of 15 April there there be a total eclipse of the Moon. This eclipse occurs mostly at twilight in the eastern and central states (Western Australia misses out entirely).

In both the eastern and central states the Moon rises eclipsed just as the sun sets, which will be a rather unique sight if you can find a flat, obscured horizon.  To see the dim coppery moon climb above the horizon will be a most unusual sight. The Moon then climbs into the twilight sky as eath's shadow moves off it and Mars pop's into view as the sky darkens.

Timings of Moon rise, sunset, mid eclipse, end of totality and end of the partial eclipse phase for major Australian and NZ cities are here.

See here for a map and contact timings in Universal Time  for sites outside Australia.


For some good tips on photographing the eclipse, see here.


If everything is clouded out locally, you can watch it live here.  


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Saturday, April 12, 2014

 

Mangrove, a floating installation

Just came back from Mangrove, a floating installation at Gallery Yampu at the old Port Adelaide Yacht Club. Had a picnic watching the fantastic structures and watching the light show. Got to eat wood fired pizza as well.

Last night is tomorrow night (sunset to 10 pm ish) , why not dress warnly and go along?

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The Twilight Lunar Eclipse of 15 April will be Cool! (with Astrophotography link)

Eastern horizon as seen from Adelaide on April 15 at 6:00 pm ACST. Totality is just ending. Click to embiggen.

In Australia, the April 15 Total Lunar Eclipse occurs mostly during twilight, with the Full Moon rising fully eclipsed, while the Sun is setting.

This can produce some dramatic images, if you have a flat horizon or an ocean horizon the copper coulourd Moon rising above it should be a magnificent sight.

But will you be actually able to see it? At twilight just at Sunset the full Moon is normally pale and washed out, surely it's eclipse dimmed face will be very hard to see?

No, as some wonderful photos from Phil Hart, a Melbourne astrophotographer show. Scroll down on this page (which has lots of handy photography hints for the eclipse, and a link to my eclipse page) and you will see some gorgeous images of twilight full Lunar eclipses.

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No, this coming Lunar Eclipse does NOT herald the End of Days

An April Lunar eclipse, the first of four consecutive total Lunar eclipses, just after the opposition of Mars, a sure sign of the End of Days ... oh, wait a minute, that's the April 24, 1967 Lunar Eclipse (just after the April 15, 1967 opposition of Mars), looks like the End of Days hasn't happened.

Predicting the End of the World (or some close approximation thereof) for astronomical events is a cottage industry that has been going on for millennia, the most recent include comet Elenin in 2011, of course the 2012 Mayan apocalypse and comet ISON in 2013 (although the doom does seem to be running out of steam lately).

Now it is Lunar Eclipses (really). If there wasn't enough real issues in the world today, Australian on-line news, the Courier Mail in Queensland, and the Mirror in the UK have been spruiking this "End of Days" nonsense which is linked to the upcoming eclipse.

This month we have a Total Lunar Eclipse coming after the opposition of Mars, in fact we will have four total eclipses of the Moon in 2014 and 2015. The Totally Eclipsed Moon is copper coloured, and Mars is red(ish), so it MUST MEAN SOMETHING!!!! Right.

Every year we have two Lunar Eclipses. To have a Lunar eclipse the Moon must cross Earth orbit when Earth is aligned with the Sun. This occurs twice a year, around 6 months apart (the drift of the timing of this occurrence means that sometimes there are more than two eclipses in a year).

While there are at least two Lunar Eclipses a year, not every year has two total eclipses, slight variations in the Earth-Moon geometry mean that sometimes we get partial eclipses, or the fainter penumbral eclipses, when the Moon passes through Earth outer shadow.

Now having four total eclipses in a row (a tetrad) is fairly rare, currently occurring every 10-20 years or so (it's more complicated than that of course). Note that world has not ended despite multiple instances of tetrads over the past few centuries. The last one was in 2003-2004 (note the world not ending) and prior to that in 1985-1986 (world failed to end again).

Or maybe you need Mars to be in opposition just before or during a tetrad (why? Because it's red of course). The chance of Mars being at opposition close to a tetrad is fairly low, but in 1967 Mars came to opposition on April 15, just before the first total Lunar Eclipse of a tetrad (on April 24 see image above). The world didn't end then either, or in 1909 when Mars came to Opposition during a tetrad, or in 1926 when Mars came to opposition shortly before a tetrad.

The take-home message is that despite multiple occurrences of Mars Oppositions/ Lunar Eclipse tetrads obet the past century there has been no "End of Days", and none in the multiple occurrences that have occured over the past millennia. So this up coming one will not be an  "End of Days" either.

I'm not sure why the newspapers are promoting this nonsense, especially since there are lots of interesting things happening in the world to sell newspapers, and since the stories are full of nonsense which can be easily checked and seen to be wromg.

The Australian on-line news quote pastor John Hagee, from San Antonio as saying
"NASA has confirmed that the Tetrad has only happened three times in more than 500 years — and that it’s going to happen now."
When a quick check shows that there were tetrads starting in 1909, 1927, 1949, 1967, 1985 and 2003.

Anyway, you enjoy the Total Lunar  eclipse of April 15, knowing the End of Days is nowhere in sight.






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Friday, April 11, 2014

 

I'm on the Radio this Sunday April 13th TWICE!

This Sunday (13th April) I'll be on the radio twice.

In the morning I'll be on ABC local radio (Adelaide 891 AM) with Ashley Walsh , going live about 10:20 am ACST (10:50 AEST). I'll be talking about the upcoming twilight Lunar Eclipse, so listen if you can (they doing streaming, so even if you are not in Adelaide you can catch this on your computer.

In the evening  at 5:30 pm ACST (6:00 pm AEST) I'll be talking on 4BC radio (QLD) about the recent NH & MRC report on homeopathy. They will also be streaming, and you can listen on-line by clicking the listen live  button on their homepage.

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Thursday, April 10, 2014

 

Observing the Opposition of Mars, 2014

The evening sky facing east in Australia on April 9 at 21:00 AEST (9:00 pm AEST) showing the Mars, Spica, Saturn and Vesta and Ceres (click to embiggen) .

The Opposition of Mars is tonight (April 9). Mars is at its biggest and brightest tonight. After this the ruddy planet will be slowly growing smaller and dimmer but for the rest of the month and into May, it still repays close attention. This post will give you a brief guide to observing this fabled world. At least for those of us not clouded out by the tropical storm about to soak Queensland.

You don't need a telescope or complicated imaging equipment to observe Mars, although a telescope or binoculars helps. Before I describe observing Mars, a few words about the opposition.

This year is a fairly poor opposition of Mars. However, it is better than the 2010 and the really poor 2012 opposition, and we will have to wait until 2018 for a really good one. What is an opposition? Opposition refers to when a planet is opposite the Sun in the sky. This can only happen to outer planets, as Earth must pass between the Sun and the planet. The Earth passes Mars in its orbit every 26 months, and at this time we get a good view of the Red Planet.

When Mars is also making its closest approach to the Sun, our view is very good indeed. While Mars is on average 228 million km from the sun, due to Mars's elliptical orbit this varies by 42 million kilometers. If Mars is at its furthest from the Sun at opposition, Mars is also around 99 million km from Earth, while if Mars is at its closest to the Sun during opposition, this value narrows to only 57 million km. Favorable oppositions occur only once in every 15 to 17 years. During the Great Opposition of 2003, Mars and Earth were a mere 55.8 million km apart. This degree of closeness will not be achieved again until 2287. This year, Mars and Earth will be 92.4 million km apart.

Oppositions in the early months of the year, when Mars is furthest from the Sun, are always poor. The best oppositions occur around August. This is very good for Southern observers, as Mars is high in the sky, and the winter sky is usually still and transparent, ideal conditions for watching Mars. This years opposition occurs during April. The conditions are reasonable for Southern Observers. The weather is cooling, reducing  atmospheric turbulence and making Mars's disk more observable. The polar cap is currently easily visible. The visible disk of Mars is now 15.1 arc seconds (an arc second is approximately 1/3600th of your fingerwidth). While this sounds astoundingly small, 15.1 arc seconds will give a smallish but passable disk in most amateur telescopes, even the small ones from Tasco.

What you can expect to see:

Unaided eye. The best observing will be from April to May. Mars rises around sunset, so Mars is best observed from 10 pm - midnight standard time for most of this period. At 11 pm AEST Mars is the brightest object in the sky, its distinctive red colour making it easy to identify (Jupiter having set). In April Mars is in the northeast, and 8 handspans above the northeastern horizon as seen from Melbourne (when your hand is held out flat, thumb in, with your arm outstretched, your hand covers 6 degrees of sky, see diagram at right, people in Adelaide and Sydney should add an extra handspan, Brisbane and Alice Springs an extra two and from Darwin Mars is 6 handspans high). See the diagram at the beginning of the post to see what you should expect.

Mars is near the distinctive bright star Spica, the brightest star in Virgo, the constellation of the Virgin. Mars is also not far from Saturn and the asteroids Vesta and Ceres. Mars is magnitude -1.5, and is the brightest object in the late evening sky. Mars fades over the month to magnitude -1, making it the second brightest object in the sky after Sirius. By the end of May it is a still bright magnitude -0.3

Aside from just watching Mars every few nights you can do more detailed observation. Plotting the position of Mars every few nights (use a torch covered in red cellophane to stop your night vision being destroyed while you draw its position) will be interesting. In mid May Mars is stationary, and reverses direction during late May. This is called retrograde motion, and occurs due to Earth overtaking Mars in its orbit. Also, by comparing the brightness of Mars every couple of nights you can plot the fall in the brightness of Mars.

Mars as seen in 10x50 binoculars on April 9. It is not exciting.

Binoculars. Mars is not visible as a disk with 10 x 50 binoculars and larger this opposition. It is not near anything interesting until late June when it comes close to Spica.

Telescopes.The best time to observe Mars is when it is highest in the sky, unfortunately this occurs around midnight for a large proportion of best viewing times. Be prepared for some late nights if you want the best telescopic views.

Mars shows clearly visible markings in a 50 mm refractor telescope (if you have a 6 mm eyepiece), and significant detail can be seen in a 4" reflector, while 6" and 8" instruments will give better detail still. No current Earth-bound telescope can reveal the huge volcano, Mons Olympus, or the huge valley of Vale Marensus, which are seen in many of the spacecraft images. However, the polar caps will be seen clearly in even a small telescope. Significant features such as Syrtis major may be visible in 4" telescopes with good eyepieces under good observing conditions (see my webcam images from 2005). See the Google Mars Map for significant Mars features, or the JPL solar system simlulator to see what part of Mars is facing you when you are observing.

Mars as seen at this opposition through a 6" reflecting telescope with a 12 mm eyepiece. You will need a 6mm eyepiece to see the markings.

The Martian day is about 40 minutes longer than the Earth day, so if you observe at the same time each night, you can see the surface features rotating into and out of view. Dust storms can also occur, sometimes lasting days. Wind removal and deposition of the reddish, iron rich dust can also reveal or obscure features, so Mars's appearance can be somewhat different between each opposition.

Seasonal winds alternately covering and uncovering darker features with lighter dust were once interpreted as seasonal plant growth. Studying the Martian storms and the changing surface features is a valuable amateur activity.

So April to May is an excellent time to dust off that old telescope lying around in the garage, or to beg a view from a friend or neighbour with a telescope. Better yet, many astronomical clubs hold open nights, and this is an excellent opportunity to see this fascinating world in a decent telescope. Also, some of the local planetariums may be showing off Mars if they have telescopes.

For recording the appearance of Mars, all you need is a sheet of paper on a sturdy background, a pencil (or coloured pencils if you want to try recording the colors you see), a small torch covered in red cellophane and a watch. Make sure you and your telescope are located in a relatively dark place, and have modest circles predrawn on your paper (I use a 20 cent piece or my telescope eyepiece cap). Have your telescope out for a while beforehand so that it is at ambient temprature, to prevent air currents in the telescope from ruining the image. Record the date and time, and the weather (if it is windy, how much cloud, how much moonlight, what is the dimmest star you can see, etc.). Make sure you are wearing warm clothing, then make yourself comfortable at the eyepiece, preferably with a chair that allows you to sit and view comfortably, and, well, start drawing. It may take a few tries before you get the hang of recording what you see by red light, but you will feel a warm glow of accomplishment when you can.

Here are some links to Mars sites of interest:

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