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Thursday, February 28, 2013

 

Comet 2011 L4 PanSTARRS tonight (28 February, 2013)

Comet C/2011 L4 PanSTARRS imaged from 20:45 ACDST at Largs Bay, Adelaide. This is a stack of 5 images each 4 seconds long at 400 ASA, 3 x zoom taken with my Canon IXUS. Images stacked in The GIMP. Comet is at the top, Fomalhaut middle left (click to embiggen, you will need to to see the comet)Single image (4 second exposure, 400 ASA, 3 x zoom, 20:45 ACDST), with the comet and Fomalhaut indicated, the comets tail can just be seen.
Singel frame taken at 9:08 ACDST (400 ASA, 15 seconds, 3 x zoom). Tail more obvious now, click to embiggen)Animation of 18 frames taken at minute intervals rom 20:50 ACDST. 400 ASA, 3 x zoom but exposure increases from 4 seconds to 15 seconds during the shoot. Click to embiggen.

After days of cloud I finally had a nother chance to see comet C/2011 L4 PanSTARRS. The sky was clear and I headed down the beach at 20:30 ACST. Using Fomalhaut as my reference (just visible low above the horizon in the twilight glow) I swept my binoculars to the right and up and almost immediately saw the pale comet in the twilight. It was much clearer than my first glimpse.

The comet had a nice, star like head and a short but clear fan shaped tail.

I started shooting images with the camera around 20:45 ACDST, starting with a 4 second exposure, and increasing as the twilight deepened. Around 21:00 I could just see the comet with the unaided eye as a faint star, no tail (before I could just detect it with averted vision). In binoculars the tail looked to be roughly 1 degree long. It was hard to be accurate with the relatively bright sky.

I couldn't estimate the brightness of the comet more than roughly, there were no decent nearby stars for comparison, all I can say was it seemed to be brighter than Magnitude 4 (and was brighter than the nearest star, which was magnitude 4.4). I'd hazard the prospects for it being at least magnitude 2 and reasonably visible to the unaided eye by March 5 are very good.

The comet was visible all the way to the horizon, although by around  21:15 it was visibly dimming in the horizon murk.

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Earth as seen from Mars on 19 October 2014, with Added Comet Siding Spring

Comet C/2012 A1 Siding Spring as seen from Mars on the 19th of October 2014, with the Moon Demios and Earth. Simulated in Stellarium. Click to embiggenComet C/2012 A1 Siding Spring as seen from Mars on the 20th of October 2014, if it hasn't impacted Mars it will be as bright as Venus. With the Moon Demios and the Southern Cross.

Strangely, one of the top searches that brings people to my blog is "Earth from Mars", so I started to provide views of Earth from Mars simulated in Stellarium (see here and here for some previous examples I have provided) .

But seeing as the story of comet C/2013 A1 (Siding Spring) potentially impacting Mars has gone viral around the world (astroblog is currently number 2 when you Google "C/2013 A1" see my previous posts here and here, with Celestia script, my post also got mentioned in New Scientist too, WOOT, along with Universe Today) I thought I would give the Earth from Mars fans something special. Earth from Mars with comet C/2013 A1 in view.

On the 19th (Mars at Adelaide equivalent time, around 18th UT) Earth is low above the eastern Martian horizon pre-Dawn, and the comet is bright and near the Zenith. By the 20th (19th UT) comet Siding SPring has zipped over to the Southern skies, and is glowing at roughly magnitude -4, as bright as Venus is in Earths skies. This should be easy to image from the Mars orbiters and surface rovers.

There is no tail on the comet because predicting tail appearance is difficult, at Mars's distance the comet may have a rather short tail.

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Wednesday, February 27, 2013

 

Spectacular Sunset, but no Comets Tonight


 

Update on Comet C/2013 A1 (Siding Spring) and a possible Mars Impact

Simulation of the close approach of C/2013 A1 to Mars in Celestia using the latest MPC elements (click to embiggen)

You may remember I posted  about a possible impact of the newly discovered comet C/2013 A1 (Siding Spring) with Mars. At the time, although an impact was possible the nominal orbit was pretty far from Mars.

Now after some more observations and refinement of the orbit, the orbital track has moved in a bit.

The nominal close approach is now  0.0007 AU. This is much closer than the previous 0.006 AU, but still further out than the 0.00023 AU close approach of 2012 DA14, which missed us by two Earth diameters.

The error associated with this estimate still includes an impact though (and a maximum miss of 0.008 AU), so an impact can't be ruled out at this stage.

As I wrote before, as further observations are added and the orbit is refined, we will have a better idea of whether it will impact. Even if it doesn't impact it will look pretty good from Earth, and specacular from Mars (probably a magnitude -4 comet as seen from Mars's surface), which might be observed by the plethora of orbitig spacecraft and the rovers. A collision would also be spectacular, but the rovers may not fare so well.

Simulation of the  of Mars and C/2012 A1 on October 19 as seen from Demios near closest approach.

Importing the latest elements into SkyMap or Stellarium suggests that from Earth we will see the comet and Mars less than a minute of arc from each other, which will look quite nice in telescope eye pieces (but hard to image as the comet will be a dim magnitude 8.5 and Mars bright).


Other takes on the possible collision from Leonid Elenin, Discovery News and IceInSpace.

UPDATE: Universe Today used my Mars simulation oicture in one of their stories WOOT! The laso quote Leonid. See it here.

I've also updated the  Celestia file I made for you. As usual, copy the code below and save as it as a text file 2013A1.ssc in the Celestia extras folder.
======================2013A1.ssc=============================
"Siding-Spring:C2013 A1" "Sol"
{
#Close approach of this comet to Mars
Class "comet" # Just copying the data for Halley
Mesh "halley.cmod"
Texture "asteroid.jpg"
Radius 3 # best guess at maximum semi-axis
MeshCenter [ -0.338 1.303 0.230 ]

EllipticalOrbit
{
Epoch 2456956.61619 #2014 25 Oct
Period 541105.4105
#SemiMajorAxis -3613.3711384783
PericenterDistance   1.401104       
Eccentricity 0.999789
Inclination 129.0291
AscendingNode 300.9777
ArgOfPericenter 2.4445
#MeanAnomaly 359.9970184682824   
}

# Again, this data is copied straight from the ssc files for Halleys’ Comet
# chaotic rotation, imperfectly defined:
# this version from "The New Solar System", 4th Edition; Eds.
# JK Beatty, CC Petersen, A Chaikin
PrecessingRotation
{
Period 170 # 7.1 day axial rotation period
Inclination 66
PrecessionPeriod 3457004.12 # 3.7 day precession period
}

Albedo 0.8
}
===========================================================

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Tuesday, February 26, 2013

 

Carnival of Space #290 is Here!

Carnival of Space #290 is now up at Venus Transit. There's a commercial Mars flyby, finding exoplanets in habitable zones, 3D printing for making astronauts food, the passing of David McKay and much, much more. Zap on over and have a read.

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The Sky This Week - Thursday February 28 to Thursday March 7

The Last Quarter Moon is Tuesday March 5. Comet 2011 L4 PanSTARRS may be visible to the unaided eye in the evening twilight. Jupiter is prominent in the early evening sky. Saturn enters the late evening sky with the waning Moon close to Saturn on Saturday March 2. Venus is lost to view. Comet C/2012 F6 (Lemmon) continues to brighten.


Sky on Saturday March 2 looking east as seen from Adelaide at 23:45 local daylight saving time in South Australia. The inset shows a telescopic view of Saturn at this time. Similar views will be seen elsewhere at the equivalent local time (click to embiggen).

The Last Quarter Moon is Tuesday March 5.

Saturn is now visible above the eastern horizon before midnight. Saturn climbs higher in the evening sky during the week, becoming easier to see. On the evening of Saturday March 2 the waning Moon is close to Saturn.

Saturn is still better telescopically in the early morning. Saturn is in the constellation of Libra.

Mercury  is lost in the twilight. It will return to the morning skies next week.

Bright white Venus  is lost in the twilight.

Evening sky on Tuesday March 5 looking west as seen from Adelaide at 8:45 pm local daylight saving time in South Australia (about an hour after sunset). The inset shows the binocular view around comet PanSTARRS. Similar views will be seen elsewhere at the equivalent local time (click to embiggen).


Comet C/2011 L4 PANSTARRS has been seen in binoculars in the evening low in the twilight. It is sporting a nice little tail. If you try looking an hour after sunset you will see it very low above the horizon.

The comet is brightening as it comes closer to the Sun than the orbit of Venus. This coming week, in the period of March 5- March 10, will be the best time to see the comet as it rises higher in the evening twilight and brightens.

To have a decent chance to see the comet you will need a fairly level, clear horizon like the ocean, and watch carefully as the twilight deepens. Binoculars should pick it up fairly easily (it is quite clear in my 10x50's), whether you can see it with the unaided eye will depend on how murky your local horizon is. For many people though I would think that they should be able to see it at least faintly. For detailed viewing instructions see here.


Evening sky looking North-west as seen from Adelaide at 22:00 pm local daylight saving time on Saturday March 2. The inset shows Jupiter's Moons at this time. Similar views will be seen elsewhere at the times indicated here.  Click to embiggen.

Jupiter is visible all evening, and is the brightest object in the evening sky.



Jupiter is prominent in the northern early evening sky, being quite visible in the twilight. Jupiter is highest in the north by 7:00 pm, setting around midnight. Jupiter is below the Hyades, near the red star Aldebaran. Jupiter remains near Aldebaran during the week, making it look as if the Bull has two eyes.

Jupiter, Aldebaran and the white star Rigel in Orion form a long line in the sky. With the Pleiades cluster and the constellation of Orion close by, this is a beautiful sight.

Now is a perfect time to observe Jupiter with a telescope of any size in the evening. Jupiters' Moons are easily seen in binoculars, and can be followed from night to night changing position.

Mars is lost in the twilight.



Comet C/2012 F6 Lemmon's location as seen from Adelaide at 22:00 ACDST on Saturday 2 March.  Similar views will be seen elsewhere in Australia and New Zealand at equivalent local times.  (click to embiggen).

Comet  C/2012 F6 (Lemmon) is a nice little binocular comet.  in binoculars is is a fuzzy disk a bit smaller than the globular cluster 47 Tucanae. The comet is brightening and is visible as a fuzzy dot to the unaided eye in dark sky locations. With the Moon rising later and later in the evening, it should be good viewing by the end of the week. 


You will need to use binoculars in suburban locations (and dark  sky locations around the full Moon), and to see it at its best you need a telescope or binoculars.

For charts, printable spotters maps and observing hints, see this page.

There are lots of interesting things in the sky to view with a telescope. 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 AEDST. For further details and more information on what's up in the sky, seeSouthern Skywatch.

Cloud cover predictions can be found at SkippySky.

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Monday, February 25, 2013

 

Birthday Comets (PanSTARRS and Lemmon, 25 February 2013)

Image of Comet C/2011 L4 PanSTARRS taken with my Canon IXUS 100 1S, 15 second exposure at ASA 400 and 3x Zoom. The image was taken at 21:15 (approx) ACDST at Largs Bay, Adelaide on 25-02-13. At this time the comet was just 3 degrees above the horizon. Click to embiggen to see things clearlyComparison image simulated for the same local time in Stellarium. In the real image Fomalhaut is just behind the tree tops.

I had a very nice Birthday dinner with the family, then relaxed with Big Bang Theory and home-made ice-cream sundaes. After days of cloud or having clear nights but other obligations that preculded skywatching, I decided to try for comet PanSTARRS again.

With Smallest one heading off to bed, I grabbed my 10x50 binoculars and headed out to see if I could see C/2011 L4 PanSTARRS. I didn't have much hope as CometAl hadn't seen anything in 7x50's last night (though he did get a good image).

But as soon as I swept my binoculars along from Fomalhaut I saw it, as clear as a bell. There was a really obvious little tail too. This was at 9:05 pm, with the comet a scant 6 degrees above a slightly cloud hazed horizon.

After glorying in the sight of this comet (finally!!!), and trying to get an estimate of its magnitude (in out defocus method, definitely brighter than Delta PsA (mag 4.2) but by how much I can't say), I hurried back home to get my camera.

By the time I got back and set up, the comet was only 3 degrees above the horizon and deep in the mruk, but still readily identifiable in binoculars. I took some shot with normal Zoom and 3x Zoom, the 3x Zoom came out best, with the comet just identifyable (in the embiggened image you can see the tail).

Now that was a good birthday present, tomorrow, I will try and catch it earlier.

After catching the comet I had a few domestic chores (went out to buy milk), I cam back and had a look for 2012 F6 Lemmon. It was really quite obvious even in the Moonlight. Hard to judge how bright, but probably dimmer than 47 Tucanae. It was like greeting an old friend.

All in all, a pretty good birthday (a great statistics workshop, schnitzel with the family and two great comets).

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Birthday Rainbow

Spectrum on the wall of the Largs Pier Hotel where we had birthday schnitzel

 

Book Review: How it Began

There is a well-known (at least in Geek circles) movie called "Powers of Ten", which starts of at the atomic scale and pulls back its focus, (in powers of ten of course) until we see the Earth, then the solar system, then the galaxies beyond.

Chris Impey uses a similar approach in his book "How it Began", only as well as going up from Earth to solar system to the galaxy and beyond, he takes us back in time as well, to where it all began. Doing a good, accessible book on the origin of the Universe is always a hard task, as our ideas on the origin may seem simple but have hidden, lurking complications in them.

By starting with the familiar, Chris sneaks up on these central ideas a step at a time, in an engaging way. As well as the central time travel metaphors, each chapter is top and tailed with the authors imagined viewpoint of this journey. I was a bit less enthusiastic about this device, sometimes it worked well, and sometimes it felt a bit contrived. I suspect this is more to do with how I visualize the same events (one day, Chris, myself and Larry Niven can get together and discuss what would happen to an astronaut on Pluto), but the critical thing is that these bookends didn't distract from the story.

In each section Chris mixes explanation, historical snippets and his own personal experience. As he has a wealth of directly relevant personal experience these episodes enhance the story rather than diverting it (I winced in sympathy at the story of shattered glass astrophotography plates). They are welcome rests on the path to enlightenment.

In a book where you are trying to explain abstruse physical theory, where the scale of the universe beggars our own earthbound experience, metaphors and analogy will inevitably be used. Chris does these devices well, I found one a little strained, but the majority were fresh, clever and very helpful (I really liked the dancer in the white suit with a partner in a dark dress for explaining Doppler wobbles for detecting exoplanets, but the analogy of the shadow of his partners feather boa to explain transits didn't work for me).

The mark of a good book is when you learn something new about a field you thought you had covered, and despite having a reasonable familiarity with most of the material, I learnt a thing or two from this book. I didn't know about the race to measure parallax for example. Even if you are well versed in these areas, Chris's book tells the story in such a refreshing way that it is worth reading to see how he explains it.

Explaining our theories of how the Universe began is always fraught, but Chris does it with aplomb, the steps leading up to string theory, and the shattered hopes that came with it are well described, the various "what caused the Big Bang" ideas are fairly surveyed. One of the things I really liked was the clear explanation of the various versions of "alternative universe" theories, which often leaves people puzzled. In fast moving fields like observing exoplanets, events have caught up with the book, but in a good way. A couple of places I found myself saying "yes, you called it".

Despite the recent advances this book will relevant for many years to come. From Earth to exoplanets, from dark matter to the Big Bang, Chris covers them all with aplomb, as we might expect from someone who teaches cosmology to Buddhist monks.

If you don't have much background in astronomy and want to learn more about the Universe, this book is for you. Even if you have a very good grounding in cosmology, this book is worth a read for the historical perspectives and the personal tales, and the analogies which you can pinch to explain things to your friends.

I give it four and a half out of five Quasars.

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Sunday, February 24, 2013

 

Comet 2012 F6 Lemmon 15 February 2013

Stack of 12 x 30 second exposures of comet C/2012 F6 taken on 15 February 2013 using iTelescope T12. Images registered on the comet and stacked in ImageJ, coveted to a Median Z project to bring out the detail in the tail. Same as the other image but with a SUMMED Z stack, trying to bring out fainter details. Comet coma is over exposed. Click on any image to embiggen.

I have finally finished processing my images of C/2012 F6 Lemmon from the 15th (only took a week and a half, but 2012 DA14 and an occultation and a bunch of other stuff came up (like my sons 16th birthday party).

I'm not sure I'll get any more of this comet using the iTelescopes, it's pretty close to their limit of travel towards the horizon. This was meant of be part of a mosaic including 47 Tucanae, but the second imaging run crashed (maybe do to the cloud which affected these images). But that doesn't matter, amazing detail.



Animated GIF of the comet (12 images every 30 seconds).



YouTube animation

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Saturday, February 23, 2013

 

EldestOne has a Birthday Party

With much swimming, table tennis, trampolining (until they destroyed the trampoline) and the obligatory computer games.

Friday, February 22, 2013

 

Readers Images of The Occultation of Jupiter, 18 February 2013 #2

Reader Chris Wyatt sends in this image (click to embiggen). I'll let him tell it in his own words.

Please find attached one of my best photos of the Jupiter Moon conjunction taken thru my 100 mm dob telescope, about 1 hr 20 min before Jupiter was run over by the Moon. I used my Canon S2 IS camera set at 400 ASA F6.3 for 1/80 sec with telescope camera combo set @ 18 magnification.

High cloud and smoke affected photos just 20 minutes later and got worse as the conjunction progressed, making it difficult to get good quality photos. Watched thru the scope as Jupiter slowly disappear behind the Moon, as the Moon disappeared behind trees.

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Thursday, February 21, 2013

 

Readers Images of The Occultation of Jupiter, 18 February 2013 #1



Reader Andrea Deegan sends in these images from Albany WA, taken between 7.47pm and 7.49pm (AWST), on February 18 2013. Nice definition in the Moon and you can see Jupiter just going behind the edge of the Moon in the third image (click to embiggen).

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Tuesday, February 19, 2013

 

Carnival of Space #289 is Here!

Carnival of Space #289 is now up at Everyday Spacer. There's a few posts on the Russian Meteorite, the first sample of martian bedrock, a few posts on commercial space companies, an invitation to name the Moons of Pluto and much more, head on over for a read.

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The Sky This Week - Thursday February 21 to Thursday February 28

The Full Moon is Tuesday February 26. Jupiter is prominent in the early evening sky. Saturn enters the late evening sky. Venus is lost to view. Comet C/2012 F6 (Lemmon) continues to brighten. Comet 2011 L4 PanSTARRS just visible in the evening twilight.


Midnight sky on Saturday February 23 looking east as seen from Adelaide at 12:00 am local daylight saving time in South Australia. The inset shows a telescopic view of Saturn at this time. Similar views will be seen elsewhere at the equivalent local time (click to embiggen).

The Full Moon is Tuesday February 26.

Saturn is now visible above the eastern horizon before midnight. Saturn climbs higher in the evening sky during the week, becoming easier to see.  Saturn is still better telescopically in the early morning. Saturn is in the constellation of Libra.

Mercury  is lost in the twilight.

Bright white Venus  is lost in the twilight.

Evening sky on Monday February 25 looking west as seen from Adelaide at 9:00 pm local daylight saving time in South Australia (about an hour after sunset). The inset shows the binocular view around comet PanSTARRS. Similar views will be seen elsewhere at the equivalent local time (click to embiggen).


Comet C/2011 L4 PANSTARRS has been seen in the morning with the unaided eye, and just seen in the evening low in the twilight. If you try looking an and a half hour before dawn you may see it very low above the horizon.

The comet is brightening as it comes closer to the Sun than the orbit of Venus. It has been spotted low in the evening twilight to the east. The comet appears to be brightening more slowly than predicted, and it is hard to estimate how bright it is in the reports I have seen, possibly around magnitude 4, certainly visible in binoculars and photographable.

To have a chance to see the comet you will need a fairly level, clear horizon like the ocean, and watch carefully as the twilight deepens. Binoculars have been used to see it, whether you can see it with the unaided eye is not clear (I haven't but the horizon was particularly murky when I tried). For detailed viewing instructions see here.

In late February/early March this may be a good unaided eye comet.

Evening sky looking North-west as seen from Adelaide at 22:00 pm local daylight saving time on Saturday February 23. The inset shows Jupiter's Moons at this time. Similar views will be seen elsewhere at the times indicated here.  Click to embiggen.

Jupiter is visible for most of the night, and is the brightest object in the evening sky.



Jupiter is prominent in the northern early evening sky, being quite visible in the twilight. Jupiter is highest in the north by 8:00 pm, setting around 1 am. Jupiter is below the Hyades, near the red star Aldebaran. Jupiter remains near Aldebaran during the week, making it look as if the Bull has two eyes.

Jupiter, Aldebaran and the white star Rigel in Orion form a long line in the sky. With the Pleiades cluster and the constellation of Orion close by, this is a beautiful sight.

Now is a perfect time to observe Jupiter with a telescope of any size in the evening. Jupiters' Moons are easily seen in binoculars, and can be followed from night to night changing position.

Mars is lost in the twilight.



Comet C/2012 F6 Lemmon's location as seen from Adelaide at 22:00 ACDST on Saturday 23 February.  Similar views will be seen elsewhere in Australia and New Zealand at equivalent local times.  (click to embiggen).

Comet  C/2012 F6 (Lemmon) is a nice little binocular comet.  It is brightening rapidly, and is visible as a fuzzy dot to the unaided eye in dark sky locations. However, the brightening Moon will make it difficult to see by the end of the week. 


You will need to use binoculars in suburban locations (and dark  sky locations around the full Moon), and to see it at its best you need a telescope or binoculars.

For charts, printable spotters maps and observing hints, see this page.

There are lots of interesting things in the sky to view with a telescope. 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 AEDST. For further details and more information on what's up in the sky, seeSouthern Skywatch.

Cloud cover predictions can be found at SkippySky.

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Monday, February 18, 2013

 

Tonights Occultation Clouded Out Here

Jupiter near the Moon in daylight, 15 minutes before Sunset. Shortly after this the cloud came over and squatted on us (click to embiggen).

No occultation for me tonight.

NOOOOOOOO!!!!!!

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Sunday, February 17, 2013

 

Occultation of Jupiter, Monday 18 February, 2013

Evening sky looking North-west as seen from Adelaide at 22:45 pm local daylight saving time on Monday February 18. This is just before the Moon covers Jupiter. The inset shows Jupiter's Moons at 10:48 ACST, just before Ganymede is covered by the Moon. Similar views will be seen elsewhere at the times indicated in the table below.  Click to embiggen.A larger view of the same event simulated in Stellarium, just before Ganymede is occulted (covered) by the Moon at 10:48 ACST.

On the evening of Monday, February 18, the Moon will occult (cover) Jupiter in Southern Australia (everywhere else sees it very close).  It will be quite spectacular with Jupiter's Moons being covered by the dark side of the Moon just before Jupiter.

While the sight of Jupiter winking out behind the dark edge of the Moon will be spectacular to the unaided eye, this is far better seen in binoculars, or better in a small telescope.

As a bonus, many places will see the occultation of the 5th magnitude star Omega Tauri before the main event.


The event does occur around 11 pm or so (earlier in WA which has the best views again). It's pretty easy to see where it is happening (just look for the Moon). Note Ganymede disappears before Jupiter and the other Moons after.




PlaceDisappears Dark Limb Reappears Bright Limb
Adelaide23:00 ACDST23:37 ACDST
BrisbaneClose Approach-
CanberraGraze Nearby-
DarwinClose Approach-
Hobart23:21 AEDST00:13 (19th) AEDST
Melbourne23:33 AEDST00:10 (19th) AEDST
Perth19:39 AWST20:45 AWST
SydneyClose Approach-

More cities and towns  can be found at the IOTA site (UT times only).

At mid graze/occulation, the Moon will be quite low to the horizon, so if you are using a telescope, make sure it has a clear horizon and can travel down reasonably well. It is advisable to set up and practise on the Moon and Jupiter a day or so before the event, so you are familiar with your telescope set-up.

Set up at least half an hour ahead of time so that you can be sure everything is working well and you can watch the entire event comfortably (trying to focus your telescope on Jupiter moments before the occultation will cause a lot of unnecessary stress). Also, setting up early allows your eyes to adapt to the darkness.

If you are using binoculars, try leaning them on a fence or the back of a chair so that the don't wobble all over the place. Better yet, see if you can get a binocular mount, you won't regret it.

This is also an opportunity to see Jupiter in the daylight. Using the Moon as your guide, you should be easily able to see Jupiter with the unaided eye 15 minutes before Sunset, and 30 minutes before Sunset using binoculars. Make sure the Sun is hidden behind something big like a wall to avoid accidental exposure to the sun.

More posts on seeing planets in daylight (with hints and tricks), are here.

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2012 DA14, images of the flyby


Asteroid 2012 DA14 imaged with the iTelescope T12 in Vela shortly after 18:35 UT (5:35 am Saturday 16 February at Siding Spring Observatory). At this time the asteroid was moving a whopping 2432.75"/minute, that's around 0.6°, or just over the diameter of the full Moon in a minute. Image cropped down from the full size exposure, this is a single 30 second luminance exposure. Overlay of all 3 images I captured in T12, you can just see the third one as it disappears off the bottom. Images stacked and registered using ImageJ. Click to embiggen.

This was the most challenging near-Earth Asteroid I have ever imaged, more challenging than 2011 MD, which came within the geosynchronous satellite orbits as well, or 2012 TC4 (0.2 Earth Moon distances) and way easier than 2012 QG42 (7.4 Earth-Moon distances).

Telescope Campaign:  

What I did right: I used my standard technique, which is to choose a star not far from where the asteroid would be, and set that as the target, then wait for the asteroid to zoom by. "Would be" was the operative word. The asteroid was moving so fast that by the time the telescope slewed to the position were the asteroid was, it would have moved out of frame.

I measured the time T12 took to slew, autofocus and begin imaging in a series of recent images, and used the average time from start of my run to actual imaging (around 5 minutes) to set the telescope position.That worked nicely, and I caught the asteroid in frame.

What I did wrong: 30 second exposures! What was I thinking? The asteroid was bright, and when moving at a hooting 0.6° across a field that is only about 3° wide, you aren't going to get many images (adding in the downtime between exposures), I should have gone for 10 second exposures.

I also should have set up imaging runs for Saturday night on the New Mexico scope, but I was exhausted and had to get up at 3:30 am to do my visual observing, so I neglected that. Mistake.


Animated gif of 2012 DA14 zipping across teh T12 field of view (open in a new tab or window to embiggen).

Visual Campaign:  

I got up at 3 am to find cloud, not entirely surprising given the huge thunderstorm we had earlier. I popped in and out until 4:00, then made a serious effort to locate the asteroid.

My original plan had been to set up the 4" Newtonian  telescope on mu Velorum and wait for the asteroid to get into view as with the iTelescopes, then manually track it.

But there was so much cloud about that even finding bright stars was a problem. A breif gap would appear and by the time I would try to manually slew to the location the cloud would be over again.

So I abandoned the telescope tried squatting with the 10x50 binoculars on the base of Crater, where the asteroid would come through at around magnitude 7.2. But cloud foiled me again. I did see a few shooting stars and a number of dim satellites (so many!) though.

The sky was paling as nautical twilight passed and I scanned the "leg' of Leo, without much hope and then I saw a brightish object in binoculars, not visible to the unaided eye, moving down the leg of Leo at just the right time. It seemed to be moving a little fast, but checking back the asteroid was moving at 0.9° a minute, which was consistent with what I saw. I've also checked with all satellite overpasses then, and nothing was anywhere the vicinity at the time.

So I'm fairly  confident that I saw 2012 DA14 in binoculars, and I got it in T12. WOOT! best NEO campaign to date. (and again, a big thank you to Andrew for his SkyMap utility which allows perople to plot NEO's coming close to Earth which defeat standard plotting routines).

Of course, then I had to pack the scope away, wake MiddleOne and take him to tennis. No rest for the wicked (but I missed the opportunity to do a radio interview on the flyby and the Russian meteor by not checking my email before I took him to tennis...sigh).



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Friday, February 15, 2013

 

Live Broadcasts of the 2012 DA14 Flyby

If, like me, you will be clouded out (or in daylight) during the 2012 DA14 flyby, you can see it live from

SLOOH (02:00 UTC 16th)

NASA TV (starts 19:00 UT 15th)

The Virtual Telescope Project.(22:00 UT 15th)

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Thursday, February 14, 2013

 

Binocular Map of 2012 DA14


Printable black and white spotter map showing the course of asteroid 2012 DA14 during the morning of February 16 (15 UT). The map is for 05:00 hours ACDST and is the view from Adelaide, similar views will be seen at equivalent local times. The tick marks for the asteroids position are every 15 minutes. The map is for daylight saving time, but the asteroid positions are labelled for standard time (you will have to add one hour in your head). The map is oriented to the west, it's a bit cluttered, but the photorealistic version below will help guide you (click to embiggen and print).
Printable black and white binocular map of 2012 DA14's path, use the spotter map to orient yourself. The tick marks for the asteroids position are every 15 minutes. The big circle is the field of view of 10x 50 binoculars. The little circle shows the position of the asteroid as seen from Siding Springs to illustrate the effect of parallax. The map is for daylight saving time, but the asteroid positions are labelled for standard time (you will have to add one hour in your head). Click to embiggen and print. When using the maps, use a torch with red cellophane over the business end so as to not damage your night vision.

 Asteroid 2012 DA14 as seen from Adelaide at 5:00 (5:00 am) ACDST, facing west. The crosses mark the location of the asteroid at the indicated times, and it's magnitude at selected times. at 5:30 the asteroid will be in the base of the constellation crater, the cup. Similar views will be seen from other locations at the equivalent local time (click to embiggen).
Thanks to Andrew for the terrific SkyMap Pro utility which turns JPL HORIZONS data into map overlays, which gets around the osculating elements problem with close approaching objects.

General viewing hints are here.

As you can see from the binocular map above with the large difference between Siding SPrings and Adelaide, because the asteroid is so close, there is a big difference in it's location from different parts of Australia.  Binocular users should get general charts from Heavens Above specific to their location, and the use the binocular chart above to guide them. While there is a substantial difference, the asteroid should be within a binocular field of the position indicated.

Telescope users should get an ephemeris from the Minor Planet Centre, specific for their latitude and longitude, and use this in conjunction with charting programs. The asteroid is visibly moving (like  a very slow satellite), so should be relatively easy to spot.

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Wednesday, February 13, 2013

 

New Posts on Asteroid 2012 DA14

The ABC has an article of mine on how to see the the close approach of asteroid 2012 DA14 using binoculars (and some handy ways to visualise the scale of the encounter).

And I've just published an article in  The Conversation about the loss of asteroid hunter Rob McNaught's funding and what it means for detecting potentially hazardous objects using 2012 DA14 as an example. 


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Tuesday, February 12, 2013

 

Carnival of Space #288 is Here!

Carnival of Space #288 is now up at Dear Astronomer. There's space drives, the amazing tale of Soyuz 18a, billions of Earth-like planets, phantom Moons and a lot lot more. Head on over for a read now!

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The Sky This Week - Thursday February 14 to Thursday February 21

The First Quarter Moon is Monday February 18. Jupiter is prominent in the evening sky and is occulted (covered) by the Moon on the evening of the 18th. Saturn is visible high in the morning sky. Venus is low on the horizon and is lost to view this week. Asteroid 2012 DA14 zips by on Saturday morning. Comet C/2012 F6 (Lemmon) continues to brighten and passes close to the Small Magellanic cloud.


Morning sky on Sunday February 17 looking east as seen from Adelaide at 3:00 am local daylight saving time in South Australia. The inset shows a telescopic view of Saturn at this time. Similar views will be seen elsewhere at the equivalent local time (click to embiggen).

The First Quarter Moon is Monday February 18.

Saturn is now readily visible above the north-eastern horizon before dawn. Saturn climbs higher in the morning sky, becoming easier to see.  Saturn rises shortly before midnight, so it is high enough to be worthwhile in a small telescope in the pre-dawn dark. Saturn is in the constellation of Libra.

Mercury  is lost in the twilight.

Morning sky on Saturday February 16 looking east as seen from Adelaide at 6:00 am local daylight saving time in South Australia (about 3/4 of an hour before dawn). Similar views will be seen elsewhere at the equivalent local time (click to embiggen).

Bright white Venus is now quite low above the eastern horizon, really only visible half an hour before sunrise and hard to see from cluttered horizons. This is the last week Venus can be seen before it is lost in the twilight.

Venus spends the week in Capricornius.

Comet C/2011 L4 PANSTARRS  is brightening, and has been (just) seen in the morning with the unaided eye, but is rapidly washed out by the advancing twilight. If you try looking an and a half hour before dawn you may see it very low above the horizon.

From the 14th the comet may be visible in the evening twilight to the east. The comet appears to be brightening more slowly than predicted, and it is not clear how bright it will be when it appears in the evening. To have a chance to see the comet you will need a fairly level, clear horizon like the ocean, and watch carefully as the twilight deepens. Binoculars may be needed to see it. For detailed viewing instructions see here.

In late February/early March this may be a good unaided eye comet.

Evening sky looking North-west as seen from Adelaide at 22:45 pm local daylight saving time on Monday February 18. this is just before the Moon covers Jupiter. The inset shows Jupiter's Moons at 10:48 ACST, just before Ganymede is covered by the Moon. Similar views will be seen elsewhere at the times indicated here.  Click to embiggen.

Jupiter is visible for most of the night, and is the brightest object in the evening sky.
on the evening of Monday February 18, most of Southern Australia will see the Moon cover (occult) Jupiter and its Moons. 


This occurs late in the evening, with the Moon relatively close to the horizon (except in Perth, where it is early evening). As the in un-illuminated half of the Moon covers Jupiter, this will be easy to see with the unaided eye, binoculars or a telescope (although of course a telescope is best). if you are using binoculars, stabilise them on a chair or fence (or a binocular mount if you have one) so that the image doesn't wobble all over the place.

Exact timings for the disappearance and reappearance of Jupiter for various cities can be found here. Note that Ganymede disappears before Jupiter, so start watching earlier. It is always best to set up at least half an hour beforehand, so your eyes can adapt to the darkness, and you can orient yourself and set up any equipment that you may have. 


The rest of Australia sees the pair very close together, which will look marvellous in its own right. 


Jupiter is prominent in the northern early evening sky, being quite visible in the twilight. Jupiter is highest in the north by 8:00 pm, setting around 1 am. Jupiter is below the Hyades, near the red star Aldebaran. Jupiter remains near Aldebaran during the week, making it look as if the Bull has two eyes.

Jupiter, Aldebaran and the white star Rigel in Orion form a long line in the sky. With the Pleiades cluster and the constellation of Orion close by, this is a beautiful sight.

Now is a perfect time to observe Jupiter with a telescope of any size in the evening. Jupiters' Moons are easily seen in binoculars, and can be followed from night to night changing position.

Mars is lost in the twilight.


Asteroid 2012 DA14 as seen from Adelaide at 5:00 (5:00 am) ACDST, facing west. The crosses mark the location of the asteroid at the indicated times, and its magnitude at selected times. at 5:30 the asteroid will be in the base of the constellation crater, the cup. Similar views will be seen from other locations at the equivalent local time (click to embiggen).

Asteroid 2012 DA14 zips across our morning skies on Saturday February 16. It will be bright enough to see in binoculars before astronomical twilight in Adelaide (5:19 am), and is at its brightest just after nautical twilight (5:52 am). After this the sky is too bright to see the asteroid (and it is too low). Similar views will be seen in central and Western Australia, with Western Australia having the best views. From most of the east coast the asteroid is too deep in twilight for the asteroid to be picked up in binoculars.

Because the asteroid is so close, there is a big difference in its location from different parts of Australia. Binocular users should get charts from Heavens Above specific to their location, telescope users should get an ephemeris from the Minor Planet Centre, specific for their latitude and longitude, and use this in conjunction with charting programs. The asteroid is visibly moving (like a very slow satellite), so should be relatively easy to spot.


Comet C/2012 F6 Lemmon's location as seen from Adelaide at 22:00 ACDST on Thursday 14 February. The location of the bright globular cluster 47 Tucanae is indicated.  Similar views will be seen elsewhere in Australia and New Zealand at equivalent local times.  (click to embiggen).

Comet  C/2012 F6 (Lemmon) is a nice little binocular comet. The best view of this visit occurs this week when the comet will pass close to the Small Magellanic Cloud on February 14-15.

 It is brightening rapidly, and is visible to the unaided eye in dark sky locations. You will need to use binoculars in suburban locations though, and to see it at its best you need a telescope or binoculars.

For charts, printable spotters maps and observing hints, see this page.

There are lots of interesting things in the sky to view with a telescope. 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 AEDST. For further details and more information on what's up in the sky, seeSouthern Skywatch.

Cloud cover predictions can be found at SkippySky.

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Sunday, February 10, 2013

 

Science Trivia Quiz, Monday February 11, 2013.

The Australian Science Communicators SA is kicking off 2013 with a Science Trivia Quiz. Bring your friends to make a table of eight or join one on the night.
Test your science knowledge against some of the biggest science nerds in Adelaide!
.

WHEN: Monday, February 11, 2013 from 6:00 PM to 8:00 PM

WHERE: The Science Exchange,
55 Exchange Place
Adelaide, South Australia 5000
Australia

ENTRY ASC Members - $5. Non-members - $10 (or sign up for ASC membership on the night & pay members price: $88.00 for individuals; $35.20 for Associates & Students).

Food/Drink: Bar available. Finger food provided.

Please book through http://ascsciencetrivia.eventbrite.com.au/

Need more info? Email: ausscicomsa@gmail.com Web: http://www.asc.asn.au/ Facebook: https://www.facebook.com/ausscicomsa

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A Busy Week Ahead (Comets, an Asteroid and an Occultation, Oh My!)

Comet C/2012 F6 Lemmon as seen from Adelaide at 22:00 (10:00 pm) ACDST, facing south. Similar views will be seen from other locations at the equivalent local time (click to embiggen).

This week is shaping up to be a busy one astronomically speaking. On Thursday the 14th and Friday the 15th the brightening comet 2012 F6 Lemmon will be close enough to the bright globular cluster 47 Tucanae for them to be both in the same binocular field. You can get a printable black and white map suitable for used with binoculars here.

Comet C/2011 L4 PanSTARRS may be visible in the evening as early as Thursday 14 February (or not). For details and guides see here.

 Asteroid 2012 DA14 as seen from Adelaide at 5:00 (5:00 am) ACDST, facing west. The crosses mark the location of the asteroid at the indicated times, and it's magnitude at selected times. at 5:30 the asteroid will be in the base of the constellation crater, the cup. Similar views will be seen from other locations at the equivalent local time (click to embiggen).

Asteroid 2012 DA14 zips across our morning skies on Saturday February 16. It will be bright enough to see in binoculars before astronomical twilight in Adelaide (5:19 am), and is at its brightest just after nautical twilight (5:52 am). After this the sky is too bright to see the asteroid (and it is too low).

Because the asteroid is so close, there is a big difference in it's location from different parts of Australia.  Binocular users should get charts from Heavens Above specific to their location, telescope users should get an ephemeris from the Minor Planet Centre, specific for their latitude and longitude, and use this in conjunction with charting programs. The asteroid is visibly moving (like  a very slow satellite), so should be relatively easy to spot.

The Moon at 10:49 pm ACDST in Adelaide on February 18 just before the Moon covers Jupiter. Similar views will be seen from other locations at the equivalent local time (click to embiggen).

On the evening of Monday, February 18, the Moon will occult (cover) Jupiter in Southern Australia (everywhere else sees it very close).  It will be quite spectacular with Jupiter's Moons being covered by the dark side of the Moon just before Jupiter.

While the sight of Jupiter winking out behind the dark edge of the Moon will be spectacular, this is far better seen in binoculars, or better in a small telescope. Detailed contact times for various locations are here.

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Friday, February 08, 2013

 

On Local Radio This Sunday (10 February)

I'll be on ABC local radio (Adelaide 891 AM) with Ashley Walsh this weekend (Sunday February 10th), going live about 11:40 am ACDST.

I'll be talking about the comets that are gracing our skies, the upcoming flyby of asteroid 2012 DA14 on February 16 and the occultation of Jupiter on February 18, so listen if you can (they doing streaming, so even if you are not in Adelaide you can catch this on your computer.

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Comet C/2012 F6 Lemmon Tonight (7 February, 2013)

Comet C/2012 F6 Lemmon sketched through 10x50 binoculars tonight at 23:00 ACDTS seen from my backyard in Adelaide. Upsilon Octanis is at the top of the field of viewComet C/2012 F6 Lemmon sketched through my 4" Newtonian with a 20 mm Plossl eyepiece tonight at 22:30 ACDTS seen from my backyard in Adelaide. The comet is slightly bigger, more circular and less intense than my sketch shows, due to my messing around in the dark


Got comet Lemmon again tonight (see my previous sketch, also got it on the 5th). Unlike the last couple of nights the sky was rather bright, possibly humidity or something increasing the light pollution. I didn't try to estimate the magnitude of the comet because of this. The sketches are still a little rough, have to put fresh batteries in my red torch and find a better something to sit on than awkwardly perching on a chair arm.

Comet was harder to pick in binoculars tonight, but showed up beautifully in my scope. Finding it in the guide scope was a pain though, so I alternated between binoculars and guide scope to star hop effectively. Didn't see a tail, but all photos of the tail show it thin and faint, not going to see it under these circumstances.

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