Astroblog

Morning sky at 5:00 AEDST facing east as seen from Sydney on Thursday, February 20. Jupiter is well above the horizon. The Moon is around 17' from Jupiter, and the pair are easily visible together in binoculars or wide field telescope eyepieces. The inset is the wide field view at 5:00 AM AEDST, when Jupiter and the Moon are closest.	Morning sky at 5:00 ACDST facing east as seen from Adelaide on Thursday, February 20. Jupiter is well above the horizon. The Moon is around 15' from Jupiter, and the pair are easily visible together in binoculars or wide field telescope eyepieces. The inset is the wide field view at 5:00 AM ACDST.	Morning sky at 3:30 AWST facing east as seen from Perth on Thursday, February 20. Jupiter is well above the horizon. The Moon is around 38' from Jupiter, and the pair are easily visible together in binoculars. The inset is the wide field view at 3:30 AM AWST.

On the morning of Thursday February 20th the Moon and Jupiter will be spectacularly close. Jupiter and the Moon are closest around 1800 UT 19 February (around 5:oo am AEDST and 4:00 am AEST, 20 Feb in Australia), but at this time the moon is below the horizon in Perth and very low  in Adelaide and Darwin. The pair will look spectacular with the unaided eye, but excellent in binoculars or telescopes (well except Perth for mots telescopes).

For Perth 3:30 am is when the Moon is nearly two hand-spans above the horizon and the Moon and Jupiter 38 arc minutes apart, very nice in binoculars but just out of reach of most wide-field telescope eye pieces.

For Adelaide 5:00 am ACDST is a good comprise, The Moon is nearly 3 hand-spans above the horizon and the Moon and Jupiter are 15 arc minutes apart.

Darwin is best around 4:30 ACST when the Moon is nearly two hand-spans above the horizon and the Moon and Jupiter are 44 arc minutes apart.

The east coast and Adelaide are favoured for telescopic views, but binocular views will be excellent from all locations.

You may wish to try some astrophotography with a mobile phone or a point and shoot camera. Follow the links for hints on imaging the Moon (and thus Jupiter) with these systems.

Labels: astrophotography, binocular, Conjunction, Jupiter, Moon, telescope, unaided eye observation

Morning sky at 5:52 ACDST facing east as seen from Adelaide on Monday, February 17, 60 minutes before sunrise. The inset is the binocular view of Mars and the nebulae on the 17th. click to embiggen	Morning sky at 5:55 ACDST facing east as seen from Adelaide on Tuesday, February 18, 60 minutes before sunrise. The inset is the binocular view of Mars and the nebulae on the 18th, when the grouping is at its most spectacular. click to embiggen

On the 17th to 19th Mars crosses between the triffid and lagoon Nebulae.O n the 18th, when the grouping is at its most spectacular. Mars is close to the waning Moon on the 19th which may make the nebulae harder to see.

Similar views will be seen elsewhere in Australia at the equivalent local time. (60 minutes before sunrise).

Labels: binocular, Mars, nebula, unaided eye observation

Recent light curve of Betelgeuse from the light curve generator at the AAVSO. I have used a mean of 3 days observations (with error bars) to give a better idea of the average brightness over time (click to embiggen).

As has been reported widely, the red-giant Betelgeuse has been dimming and is now dimmer than has been measured visually in the last 50 years.

This has caused considerable excitement in the astronomical community, but although Betelgeuse is "close" to the end of its lifespan, it is unlikely to go supernova any-time soon (maybe 100,000 years from now).

There has been a lot of speculation over why Betelgeuse is dimming. The leading theory is that it is a chance alignment of it's natural variability cycle. Betelgeuse is a variable star with a complex cycle of dimming and brightening, there is a dominant period of 420 days, superimposed on a long period of 5-6 years and a shorter-term variability of around 180 days. An early Astronomers telegram at the beginning of the "fainting"suggests that the "the current faintness of Betelgeuse appears to arise from the coincidence of the star being near the minimum light of the ~5.9-yr light-cycle as well as near, the deeper than usual, minimum of the ~425-d period".

A more recent Astronomers telegram has reported improved modelling of these cycles and predicts if the cycles are the cause, Betelgeuse should start brightening  on February 21 (± 7 days). That means it could start brightening as early at Feb 14 or as late as the 29th. Some more explanation and graphs are available at this Space Weather article (scroll down).

Whatever happens in the next fortnight and beyond, observation by multiple observers are required during this critical time period.  See spotters maps and brightness guide stars below.

Regardless of cause, Betelgeuse is the dimmest and coolest it has been since photometry began 25 years ago, and may even have shrunk to 92% of its previous diameter.



Evening sky looking north at 21:42 ACDST on Saturday, February 15 (90 minutes after sunset). Similar views will be seen elsewhere in Australia at the equivalent local time. Click to embiggen.

Orion is readily visible. Betelgeuse is the bright red star below the "saucepan" of Orion. Red Aldebaran is almost the same height above the horizon as red Betelgeuse, making brightness comparisons easy.

In order to avoid the Purkinje effect, where red stars seem to become brighter the longer you stare at them, you need to keep shifting your gaze around. Try bracketing the star with observations of stars brighter and dimmer. to get a good comparison. A more comprehensive guide to observing variable stars is here. Different observers will have slightly different estimates. My last estimate was Betelguese was a trace under 1.7 and Les Dalrymple had it a trace over. Try not to let your expectations bias what you are seeing. Comparison sttar magnitudes are given below.
 

Spotters chart of stars suitable for estimating the brightness of Betelgeuse. Nearby Aldebaran (magnitude 0.85) also red, is a good comparison star. Bellatrix, the other shoulder star of Orion opposite Betelgeuse is magnitude 1.6. The middle star of Orion's belt, Alnilam is magnitude 1.7 and Adhara in Canis Major is Magnitude 1.5. Wezen, near Adhara, is 1.8 and Saiph in Orion is 2.1.

Labels: Betelgeuse, unaided eye observation, variable star

Evening sky looking north-east at 22:18 ACDST on Saturday, January 4 (90 minutes after sunset). Similar views will be seen elsewhere in Australia at the equivalent local time. Orion is readily visible. Betelgeuse is the bright red star below the "saucepan" of Orion. Red Aldebaran is almost the same height above the horizon as red Betelgeuse, making brightness comparisons easy

Betelgeuse is a red giant star which forms a distinctive part of the Constellation of Orion the Hunter. It has shot to prominence recently as it has dimmed to levels not seen for over 25 years. It is now obviously dimmer than magnitude 0.85 Aldebaran and roughly as bright as Bellatrix, the next brightest star just to the north of Betelgeuse (see chart below). While there is a lot of excitement as Betelgeuse is likely to go supernova "soon", soon is probably 100,000 years away, and the current dimming has other explanations (see below).

While familiar to almost all casual observers of the night sky as the bright red star that forms the shoulder of Orion the hunter, most people were unaware until recently that Betelgeuse is a variable star with a complex cycle of dimming and brightening. While the variations in brightness are small they may form the basis of stories by indigenous Australians who were keen observers of nature.

Recent light curve of Betelgeuse from the light curve generator at the AAVSO.  It's a bit messy because of all the observations, but you can see that it has now dipped to around magnitude 1.7 in the latest observations.

As I said, the variability of Betelgeuse is complex, with a dominant period of 420 days, superimposed on a long period of 5-6 years and a shorter-term variability of around 180 days. The latest Astronomers telegram suggests that the "he current faintness of Betelgeuse appears to arise from the coincidence of the star being near the minimum light of the ~5.9-yr light-cycle as well as near, the deeper than usual, minimum of the ~425-d period".

It is possible that Betelgeuse is close to its minimum, so further observations are needed over the coming days. Towards the end of the week, the waxing moon will make it more difficult to estimate Belegeuses brightness.

Spotters chart of stars suitable for estimating the brightness of Betelgeuse. Nearby Aldebaran (magnitude 0.85) also red, is a good comparison star. Bellatrix, the other shoulder star of Orion opposite Betelgeuse is magnitude 1.6. The middle star of Orion's belt, Alnilam is magnitude 1.7 and Adhara in Canis Major is Magnitude 1.5. Wezen, near Adhara, is 1.8 and Saiph in Orion is 2.1.

In order to avoid the Purkinje effect, where red stars seem to become brighter the longer you stare at them, you need to keep shifting your gaze around. Try bracketing the star with observations of stars brighter and dimmer. to get a good comparison. A more comprehensive guide to observing variable stars is here. Different observers will have slightly different estimates. My last estimate was Betelguese was a trace under 1.6 and Les Dalrymple had it a trace over. Try not to let your expectations bias what you are seeing.

Labels: Betelgeuse, unaided eye observation, variable star

Venus seen in the twilight above the ocean at 20:08 ACDST. Taken with a Canon IXUS 400 ASA 1/20 minute exposure. Click to embiggen to see Venus clearly.	Enlarged crop of the area to show location of Mercury. Venus uis the bright dot above Mercury

I have been able to see Venus for about a week (more due to the weather and clouds than due to its actual visibility), and yesterday was a good opportunity to see Venus and Mercury together. Sadly, although Veus was readily visible to the unaided eye 30 minutes after sunset, Mercury is still invisible without binoculars (it did {just] show up in the photos). Venus will become more prominent over the next weeks, with a nice encounter with the thin crescent Moon on the 19th. Mercury never gets better this month.

Labels: astrophotography, Mercury, unaided eye observation, Venus

Morning sky on Saturday April 26 looking east as seen from Adelaide at 5:00 am ACST. Venus is near the thin crescent Moon. The inset shows the telescopic view of Venus at this time. (click to embiggen).

This Saturday morning will see the crescent Moon close to Venus, this will be lovely to look at, and a nice subject for photography.

Saturday morning is also a good time to see Venus in the daytime. Venus can be readily visible during the day if you know where to look. Using the Moon as a handy guide will help you find it.

Make sure the Sun is hidden behind something solid like a building or a wall when you are looking for Venus, not trees or your hand. Exposing your eyes directly to the glare of the Sun can be very dangerous and you could potentially lose your sight.

Look for the crescent Moon, and Venus should be visible as a bright dot about three finger-widths to the right of the Moon (and just slightly above it).  It's best to look just after Sunrise when the Sun is still low and the sky is less bright. You may need to look carefully for a while before Venus "pops" out at you. Sometimes locating Venus in binoculars will help with locating it with the unaided eye.

Labels: Daylight, Daytime, Moon, unaided eye observation, Venus

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:

Labels: Mars, Observational Astronomy, Opposition, unaided eye observation

Venus and Mercury as seen from Largs Bay, Adelaide on 16 June at 5:50 ACST. This was taken with my Canon IXUS at  ASA 400 and 0.4 of a second exposure. You will need to click to embiggen to see Mercury in this shot.	Venus and Mercury as seen from Largs Bay, Adelaide on 16 June at 5:55 ACST. This was taken with my Canon IXUS at 3x Zoom, ASA 400 and 0.6 of a second exposure. Unfortunately the dust on the CCD chip ruins the picture a bit. The colours were more vivid in real life.

 After more cloud finally got a view of Venus and Mercury together. they are closing in on Each other and will be closest on the 22nd. Venus is really quite easy to see now.

Labels: Mercury, unaided eye, unaided eye observation, Venus

Jupiter, Venus (just near the cloud band above the horizon) and Mercury (off to the right of Venus and above the channel light) at around 6:10 pm ACST as seen from the beach at Largs North, Adelaide. Image taken with a Canon IXUS, 3 x Zoom 400 ASA, shutter speed 2 seconds. Click to embiggen	A few minutes later, Venus is just touching the surface of the ocean, Mercury is closer to the channel light.

One of the "benefits" of being sick these past few days was that I got picked up by the Bettdeckererschnappender Weisle and the kids in the afternoon. Driving back home the clouds parted and I could see the triangle of Venus, Jupiter and Nercury just above the horizon. I pointed it out to the family, and when we got home I jumped out, grabbed the camera and was able to get off a few shots with the planets just above the horizon.

The whole thing looked really spectacular, and I'm more than slightly astounded I could see Venus all the way until it touched the horizon.

Labels: Conjunction, Jupiter, Mercury, unaided eye, unaided eye observation, Venus

Western horizon as seen from Adelaide this Friday at 5:45 pm ACST on 24 May, when Venus and Mercury are closest. Similar views will be seen from the rest of the southern hemisphere at the equivalent local time. Click on any image to embiggen	Western horizon as seen from Adelaide at 5:45 pm ACST on Sunday 26 May, when all 3 planets are within a circle 3° across.
Eastern horizon as seen from Adelaide at 5:45 am ACST on 20 April 2026, when Mercury, Saturn and Marsare within a circle less than 2° across.	Western horizon as seen from Adelaide at 6:23 pm ACST on 8 September 2040, showing all 5 bright planets and the crescent Moon..

The weather seems to be fining up, so there is a good chance we will see the main part of the planet dance under clear skies.

This Friday evening (24 May) Mercury and Venus are closest, then on Sunday evening and Monday evening (26 and 27 May respectively), Mercury Venus and Jupiter are are within a circle 3° across (that's the distance covered by three out-stretched fingers).

For more details, viewing hints and an animation, see my Planet Dance post.

The line-up is the best until 2026, when Mercury, Saturn and Mars are within a circle less than 2° across. Then in 2040, all 5 of the bright planest are close together in the evening twilight, with lots of close approachs of pairs of planets, a real planet dance to look forward to.

Labels: Conjunction, Jupiter, Mercury, stellarium, unaided eye observation, Venus

Western horizon as seen from Adelaide at 5:45 pm ACST on 24 May, when Venus and Mercury are closest. Similar views will be seen from the rest of the southern hemisphere at the equivalent local time. Click on any image to embiggen	Western horizon as seen from Adelaide at 5:45 pm ACST on 26 May, when all 3 planets are within a circle 3° across.
Western horizon as seen from Adelaide at 5:45 pm ACST on 28 May, when Venus and Jupiter are closest.	Western horizon as seen from Adelaide at 5:45 pm ACST on 31 May, when all the planets are in a straight line.

Over the next week there will be a beautiful sight as the three planets Mercury, Venus and Jupiter dance around each other in the twilight.

You don't need a telescope to see this, just your eyes. The conjunction is quite close to the western horizon though, you will need a level, clear horizon to see it at its best. Ocean or desert is best, or somewhere high.

The planets will be between 4 finger-widths (4 degrees) and a bit over a hand span (7 degrees) above the horizon half an hour after Sunset. A hand-span is the with of your hand making a "stop" sign when your arm is held out straight in front of you.

Although half an hour after Sunset is the best trade-off between visibility and hight above the horizon, I found I could see Venus and Jupiter at least 25 minutes after Sunset, you might like to try looking earlier too. Successful photography will have to wait until the sky is somewhat darker so the planets are not washed out

Mercury and Venus are closest on 24 May All 3 planets are within 3 degrees of each other on 26 and 27 May, then  Jupiter and Mercury are closest on 27 May, Jupiter and Venus are closest on 28 May. Finally all 3 form a straight line on 31 May.

The simulations exaggerate the size of the planets. This photo is more like what you will see only the planets are brighter and clearer with the unaided eye.

Venus and Jupiter as seen from Adelaide on 17 May, 2013. Imaged with a Canon IXUS, 1/4 sec exposure, ASA 400 3x Zoom at 5:55 pm ACST. Jupiter is the dot at the top right, Venus is bottom left, indicated by the yellow lines. You will need to click on the image to embiggen to see Venus clearly.



A video of the encounter is below:

Labels: Jupiter, Mercury, unaided eye observation, Venus

Jupiter, Aldebaran and the Moon as seen from Adelaide, Australia on January 22, 2013 at 10 pm local daylight saving time, looking north. Similar views will be seen from the Southern hemisphere. The Moon's size has been exaggerated for ease of viewing (click on any image to embiggen).	Jupiter, Aldebaran and the Moon as seen from Roswell, New Mexico on January 21, 2013 at 10 pm local time, looking South near the zenith. Similar views will be seen from the Northern hemisphere. The Moon's size has been exaggerated for ease of viewing (it looks like the Moon is covering Jupiter, but it doesn't).

Finding the bright planets (Mercury, Venus, Mars, Jupiter and Saturn) should be relatively easy as they are, well, bright. But as a beginner, how do you tell them from all the bright stars in the sky? Most newspapers publish rise set times for planets, but from there you can only work out the general area in the sky they will be. A good guide is that, in general, stars twinkle and planets don't. But on a still night this doesn't help (and there is a lot of sky to scan.

You can buy any number of sky charts, but they can be confusing to start off with when you are still a little unfamiliar with the sky, and the star formations are unfamiliar (by the way, I use Stellarium, a free photo-realistic sky planetarium program, it's fantastic for sky gazing. A guide to using Stellarium and some of the cool things it can do is here).

So what is a REALLY recognisable object, that is easy to find, and is close to the planets sometimes? The Moon of course. The Moon comes close to each of the bright planets at least once a month, so if you can identify the Moon, then if you know when the Moon and the bright planets are close, then it's a cinch. As well, the Moon and bright planets can form really lovely patterns in the sky.

But, of course, you need to have a list of times when the Moon is close to the bright planets. Luckily, I have one here. Of course, it is set up for Australia. As Australia is 8-10 hours ahead of Universal Time, for places behind UT (like the Americas) the occurrence will be the day before.

As an example, in about a weeks time on the 22nd of January in Australia, the Moon will be close to the planet Jupiter (see the diagram above) and make a nice formation with Jupiter and the bright star Aldebaran. For the America's this event will take place on the 21st (with the Moon really close to Jupiter). The presence of Aldebaran may be confusing, but it is a red star, while Jupiter will be a golden yellow, and the brighter of the two. Generally, the brightest object closest the Moon is the planet (Mars far from opposition is the exception).

Similarly, on February 4th in Australia, the Moon is close to Saturn, people in the Americas will see this on the 3rd, their time (see below).

People in the northern hemisphere will have a reversed view from those in the southern hemisphere, but in terms of finding things close to the Moon, this doesn't matter.

After you have identified the planets with the Moon, you can use this knowledge to spot them on subsequent nights. Of course, the planets move, but slowly, so  shortly you can become familiar enough with the sky to locate them with ease.

Only Jupiter, Saturn and Venus are visible at the moment, Mars and Mercury are hidden by the Sun. However, over the coming mnths there will be several good planet/Moon enocunters, so it is worth looking out for them.

Saturn and the Moon as seen from Adelaide, Australia on February 4, 2013 at 3 am local daylight saving time, looking east. Similar views will be seen from the Southern hemisphere. The Moon's size has been exaggerated for ease of viewing.	Saturn and the Moon as seen from Roswell, New Mexico on February 3, 2013 at 3 am local time, looking East. Similar views will be seen from the Northern hemisphere. The Moon's size has been exaggerated for ease of viewing.

Labels: Jupiter, Moon, Saturn, unaided eye, unaided eye observation, where to look

While still having very large error bars, the predictions for the Phobos Grunt reentry are becoming more certain.

Most predictions are still for 15 January UT, roughly around 20 h UT but with spreads of error on the order of 9 hours to one and a half hours (see here, here, here and here for a variety of predictions). The tightest prediction now puts the re-entry off the coast of Africa.

From Australia's point of view, the spacecraft will come down sometime on early Monday 16th, CalSky (and the Phobos Grunt site) has a pass over Adelaide at 6:54 am AEDST, with reentry at 7:12 AEDST +/- 3 hours. So it may be possible for Australians to see the craft-reenter.

Labels: Satellite, spacecraft, unaided eye observation

Morning sky looking north-east as seen from Adelaide at 5:00 am local daylight saving time on Saturday November 19 showing Mars near Regulus and the Moon, with the Leonid Meteor shower radiant indicated with a cross. Similar views will be seen elsewhere at the equivalent local time. Click to embiggen.

On the morning of Saturday November 19 the Leonid Meteor shower peaks (from the point of view of Australians, that's 18 November UT), with the best time being between 3-4 am.

Unfortunately, the Leonids radiant is just below the last quarter Moon, so very few meteors will be visible (maybe one per hour). You can use the Meteor Flux Estimator to get a prediction for your location. Use the 13 Leonids option and don't forget to set the year to 2011.

If you are going to have a look, be sure to let your eyes adjust for at least 5 minutes so your eyes can be properly adapted to the dark. Don't look directly at the radiant site, because the meteors will often start their "burn" some distance from it, but around a handspan up or to the side.

Make yourself comfortable, choose an observing site that has little to obstruct the north-eastern horizon, have a comfortable chair to sit in (a banana lounger is best), or blankets and pillows. A hot Thermos of something to drink and plenty of mosquito protection will complete your observing preparations. As well as meteors, keep an eye out for satellites (see Heavens Above for predictions from your site). The sky will also be particularly beautiful, with the constellations of Orion and Taurus gracing the north-western sky.

Labels: Meteors, unaided eye observation

Left image: Venus and Mercury lurk just above the clouds below the head of the constellation of the Scorpion on 29 October 2011. The crescent Moon fills in the scene. Centre Image: Mercury and Venus, ostensibly in the head of the scorpion, are hidden behind clouds n November 4. Right Image: Mercury and Venus above the head of the Scorpion on November 6 (Click on any image to embiggen).

Mercury and Venus are slowly climbing up the constellation of the Scorpion, naturally the more spectacular events have been clouded out. Still, the November 10 line-up with Antares should be good if the weather holds off.

Labels: Mercury, unaided eye observation, Venus

Evening sky looking west as seen from Adelaide at 8:30 pm local daylight saving time on Friday November 4, 2011 showing the Mercury and Venus in the head of the Scorpion. Similar views will be seen elsewhere at the equivalent local time. Click to embiggen.

Mercury and Venus are side by side, around 2 degrees from each other, and spend the early part of November climbing the Scorpion together.

On November 4, Mercury and Venus are in the horizontal bar of stars that make up the head of the constellation of the Scorpion. With Mercury 0.7 degrees from Delta Scorpii, this will look quite amazing. Look to the west around an hour after sunset for best viewing, although they will be low above the horizon.

On the 5th the pair are still close to the head of the Scorpion, and well worth looking out for too.

Labels: Mercury, unaided eye observation, Venus

Venus (bright dot) and Mercury (not so bright dot below and to the left) above the ocean at Largs Bay at around 8:15 pm local daylight saving time (click image to embiggen).

Labels: Mercury, unaided eye observation, Venus

Quoting Spacefilght 101 (itself quoting the German Space Agency)

"The German ROSAT X-Ray Observatory Satellite has re-entered Earth's atmosphere on Sunday, October 23, 2011 between 1:45 and 2:15 UTC .."

As yet, they are not sure if the satellite splashed down in the Indian ocean or landed in China. Read the full story here.

Labels: Meteors, Satellite, unaided eye observation

Labels: Meteors, unaided eye observation

I'm probably the only astronomy blogger who hasn't blogged about ROSAT, but hey, who am I to buck a trend? So I'm doing it now.

Anyway, the ROentgen SATellite (ROSAT) is an orbiting X-ray telescope past it's "best use by" date. Sometime between October 21 and October 24 UT, it will de-orbit, plunging back to Earth as a brilliant fireball. The most likely date is the 23rd. Like the UARS, ROSAT is large enough for big chunks of the the telescope to make it back to Earth. Maybe it will be ironic and come down during the Orionids?

While exactly when and where the satellite will fall is still uncertain, you can follow it on Heavens Above, CalSky, and SpaceWeather. There's also an iPhone app to track it, and a twitter feed.

You can use the above sites to watch for ROSAT passing overhead before it falls, sadly, I won't get to see it from Adelaide.

The Bad Astronomer, The Planetary Society Blog and Universe Today all consider the ROSAT re-entry (hat tip to Jayne Stigger).

Labels: Meteors, Satellite, unaided eye observation