Friday, February 5, 2016

Certain of uncertainty for near earth asteroids

In my continuing efforts to de-mystify the art of Asteroid Astrometry, I thought I'd follow up last week's article on about 2016 BE with a deeper examination of the Uncertainty parameter when its listed in orbital elements.

This week there is some attention on 2013 TX68 which will possibly make a record close pass of 11,000 klms or possibly be 40 times further away than the moon on March the 5th. I can see that puzzled look on your face ;-) 2013 TX68 is also a Virtual Impactor in 2017, a term we discussed last week.

So firstly lets get some perspective on this uncertainty thing.

2011 CF66 was also listed as a virtual impactor for Feb 2nd 2016, it didn't hit us, no-one was worried if it would, and in fact no-one has any idea where it actually is. It is only a tiny asteroid about 3-9m in diameter and wouldn't have done any damage even if it did. In fact there are 20 other virtual impactors listed in the Risk Table this year, the next one might approach on Feb 18th, is 2009 VZ39, and is slightly smaller than 2013 TX68. 2009 VZ39 is also in the daytime sky and not observable for follow up and further confirmation. I only highlight this to emphasise the point here - all asteroids once they are discovered need to be tracked for sometime, to improve the precision of the orbit before any pronouncements about where they are going to be at a certain point in time. The difference between 2013 TX68 and 2009 VZ39 for example is that 2013 TX68 was observed for 31 data positions (astrometry) over 3 nights where as 2009 VZ39 was observed on only one night with 8 astrometric data positions. If you look at the orbital elements for 2013 TX68 the uncertainty parameter is listed as 7, where as for 2009 VZ39 there is not even enough data to start that calculation. For 2011 CF66, there is a 1.1e-8 chance of a collision between 2016 and 2114, so its mathematically possible, but highly unlikely.

NASA/JPL produced this nice graph with it's press release this week which illustrates the point well.

Image Credit: P. Chodas (NASA/JPL)

What you see is a graphical representation of the "error bars" or the zone of uncertainty, based on the orbit elements that we currently know. This asteroid will be picked up again in future surveys and the zone of uncertainty will reduce further.

Uncertainty Parameter is quite a complex calculation, but it essentially always starts off being a "9" and reduces over ensuing months as more data is collected. Uncertainty is a table of the "Runoff" of arcsecs per decade and Level 7 just means essentially there will be less than 33,121 arcsecs of "runoff" over the next decade. You can think of this as being: in a decade the place to look will be 33,121 arcsecs bigger than the range of uncertainty we need to factor in when we look for it now.

Many of the "click-bait" bloggers and conspiracy theory followers regularly confuse Uncertainty with the Torino Scale - they shouldn't, as even WIKIpedia has a great explanation of the Uncertainty factor, however they google "Asteroid rating 7" and get a hit on what the Torino Scale is and confuse the two, without doing any further investigation. The Torino scale is a risk weighted table and ALL current Virtual Impactors are listed as Torino Level 0. The virtual impactors that are listed have "potential" collisions over a range of years and are only there because we largely don't have enough data yet to remove them.

Asteroid Apophis (99942) 2004 MN4 briefly shot up the Torino Scale to a record high Level 4, before subsequent radar imaging and 4452 observations over 10 oppositions reduced its Uncertainty Parameter to 0 and its Torino Level to 0, with an asterisk that it needs to be carefully watched. Asteroid Apophis will be a naked eye object on April 13th 2029 when it makes a very close but HIGHLY CERTAIN pass of the earth. This level of certainty is only refined by many hundreds of hours of dedicated work from professional and amateur astronomers.

Lastly, Uncertainty should not be confused with don't know, don't care, have no idea what we are doing. Its just a case of not YET having enough data, more needs to be collected.

Friday, January 29, 2016

Asteroid 2016 BE Virtual Impactor for now in 2053

UPDATE 31/1/2016: The 2053 pass has been eliminated as a risk. There are still 5 virtual impacts from 2076 - 2111. These will also likely be removed as the precision of the orbit is improved.

Tonight, tracking potential virtual impactor Asteroid 2016 BE. Its a 79m wide Asteroid discovered on Jan 16th by the Catalina Sky Survey(703).

78 positions have so far been reported from 18 different observatories, including both H06 and I89, the iTelescope.net observatories. I managed to grab another 3 positions tonight. The asteroid is starting to speed up (in terms of relative velocity against the background stars) and tonight is moving quite quickly at 19 Arcsecs per minute. As a result of the fairly bright magnitude and the fast speed, you need to take as short an exposure time as possible. However the full moon is still pretty bright I had to use 30 sec images which means the asteroid is still slightly streaked. I have used a stacking technique to make sure my residuals are still reasonably good (given it is travelling at fairly high speed).

So what actually is a "Virtual Impactor". As asteroids are tracked the length of the recorded "arc" increases - now 10 days for 2016 BE. Of course the level of precision for future positions of the asteroid increases the longer the "known arc" and therefore the ability to determine future positions of the asteroid improves as the "zone of uncertainty" reduces. As long as the "zone of uncertainty" overlaps the earth's future orbit position, the object is listed as a virtual impactor for that pass. This happens from time to time without much concern, because as the precision of the orbit improves with more observations, the object usually drops out of the risk table quite quickly.

Whilst the asteroid will make a moderately close pass in the first week of February at 5.7 Lunar distances, its important to understand that the "virtual impact" currently listed in the Sentry Risk Table is for the 3rd February 2053 .... NOT ON THIS PASS!!!! As you would expect the "zone of uncertainty" for 2053 is much large than the "zone of uncertainty" for next week. So it will take many further observations before it is (most likely) removed from the risk table. Its current risk table score of Torino-0 just means that at this point the chance of a collision in 2053 has not been able to be eliminated at this stage.

Measured position:

K16B00E KC2016 01 28.46044 12 04 01.15 +65 50 49.0 16.9 R H06

K16B00E KC2016 01 28.46319 12 04 09.44 +65 49 54.8 17.3 R H06

K16B00E KC2016 01 28.46604 12 04 18.01 +65 48 58.7 17.4 R H06

Wednesday, December 9, 2015

Variable Star workshop on KIC 8462852 at VSSEC

A big shout out to the Victorian Space Science Education Centre and Telescopes in Schools program who hosted me yesterday running a variable star workshop with students and science teachers. The staff were magnificent and the centre is a real credit to all involved.

The Mars Science Mission experience is second to none and has to be seen to be believed. My workshop involved an introduction to variable star astronomy including a worksheet exercise of basic Visual Observation Photometry, culminating with the class comparing their "visual" observation with a highly precise VPhot measurement straight from one of iTelescope.net's Telescopes.

Result: The class determined that KIC 08462852 was at its long term photometric brightness of 11.87 and provided another 32 data points to the AAVSO's long term study of the star. The target is subject of Dr Tabitha Boyajian et al's Paper KIC 8462852 - Where's the Flux (WTF) a Planet Hunter target from the Kepler Mission that exhibited some strange and difficult to explain behaviours.

In a week where Australia's STEM Future was front and centre, it was great to be out and about doing something about it.

Thursday, October 15, 2015

Asteroid 2015 TB145 (PHA) close and bright flyby Oct 31

UPDATE: Oct 31st, 2015. Live coverage of Asteroid 2015 TB145.

Image Credit: P.Lake 10 Sec image from U69 T24 - travelling at 115 arc"/m at PA 35.4 07:00 UT (Available for media use with attribution to this blog)

Compare the two images - Above a 10 sec image, Below a two minute image which was stacked for movement of the asteroid.

UPDATE: Oct 31st, 2015 - From the NASA Press release this morning the amazing radar images have shown a dark dead comet,(and I am not making this up) looks not unlike a skull. The radar run went well getting down to a resolution of 7 meters per pixel. Its interesting those depressed areas are likely impact craters or collapsed areas from which the jets emerged when the comet was active. Recent studies of 67P by Rosetta have shown collapsed areas on Comet 67P where jets seem to originate from. This comet has been long dead, some studies have already been done to check for past meteor showers originating from its orbit - see the post on the SETI Institute Blog. Also from the press realease: "NASA values the work of numerous highly skilled amateur astronomers, whose accurate observational data helps improve asteroid orbits....". I hope to have more images tonight (weather permitting) - stay tuned.

Image credit: NAIC-Arecibo/NSF

UPDATE: Oct 27th, 2015 - Great set of images last night in the pre-dawn sky from New Mexico. The asteroid has brightened to Mag 15.8 and its apparent speed across the sky is starting to increase as it gets closer. [Also I should probably point out the faint halo you may be able to see is due to the strong moonlight reflecting off some dust on the primary mirror - the full moon was only 36 degrees away]

UPDATE: Oct 24th, 2015 - Finally got some images. The asteroid has brightened considerably to Mag 16.8/9 ish. No signs of cometary activity at this point. Its moving at 0.39arc"/m in a 120 sec image (so 0.78arc" in the image)and the pixel plate scale is 0.53 arc"/pixel so you can see a hint of softness on the trailing side. Definitly no cometary activity though - that's as close as I can go to getting it as sharp as you can get it.

Image Credit: P.Lake 2015 TB145 9x120 secs on the 0.7m Burnell, Cannon, Leavitt Telescope (BCL) T27 at Q62, SSO.

UPDATE: Oct 22nd, 2015 - Getting frustrated, the observatory has been closed due to bad weather for 4 nights.

UPDATE: Oct 17th, 2015 - NASA have updated details of the planned radar runs and expect to be able to get images with a resolution of 2 meters per pixel, they expect it to be the best radar run of the year. Also one other interesting aspect is the Tisserand parameter has been calculated at 2.937 which is just lower than the theoretical "boundary" (of 3.0) between Asteroid and Jupiter Family Comets. The other target of a radar run on 29th is 2009 FD, a well studied Apollo Asteroid, has a Tisserand parameter of 5.295. The seeing was a bit poor on the 14th so the image wasn't strong enough. The relative speed (across the camera chip) will slow to only 0.17 arc"/min on the 19th so I'll be able to stack the images really deep and get a good look at it. If the seeing is better tonight we might even get some more detail. I did look a bit fuzzy the other night but as you can see in the video the satellite that trailed through was very fuzzy as well - so I'm not reading to much into that at the moment.


Image/Video Credit: 2015 TB145 from H06, 12 x 180 sec exp stacked 4x3, 0.5m Planewave October 14th - P.Lake

A couple of times a year, the asteroid surveys throw up a surprise, with a large asteroid approaching very close to the Earth, with little advance notice. After last week's blog post about the Blogsphere overeacting to an Asteroid that astronomers knew about for 15 years passing at 65 Lunar Distances (LD), the "surprise" of course had to happen this week.

This will be an interesting two weeks, as Asteroid 2015 TB145 will cruise by Earth just outside 1 Lunar distance (1.3 LD). The asteroid is a target of the Arecibo Observatory (that big antenna that rose out of the lake in the majestic James Bond scene), and to get some really great radar tracking and detailed images, the ephemeris and position of the asteroid needs very high precision.

To give you an idea of the type of imaging to be obtained (see below), a similar situation occured last year for 2014 HQ124. These were some of the best radar images ever recorded, and some of my data was used to refine the orbit for targeting on that occasion.

Image Credit: Asteroid 2014 HQ124 Radar images from Goldstone - NASA/JPL

This asteroid is twice as big (between 290 and 650 meters diameter - most astronomers are calling it about 480m) and twice as close as 2014 HQ124, so you can only imagine how good the images should be. Professional Observatories and amateur astronomers will be tracking it closely to improve the precision of the orbit as it approaches.

I was quite chuffed when tracking 2014 HQ124 that my light curve had a few bumps in it and I made the call it was "not round" which was subsequently confirmed by the radar images.

So who knows what the next two weeks will turn up? What we know at this stage is that is going to be quite bright and could be visible in binoculars. Also its speed is very fast, but its moving slowly across the images at the moment as you can see, because of the angle its approaching us at. As it makes its close approach its going to do a nice "flyby" of the Crab Nebula M1 for Northern Hemisphere viewers on Oct 29th/30th Ian Musgrave has details on his blog shortly.

So stay tuned, I'll be following it closely and providing some regular updates.

Wednesday, October 14, 2015

Rustling up more services for the bush - Sky Muster NBN1A Launch

Image Credit: P.Lake 60 Sec Luminance on Takahashi FSQ106 T12 at Q62

I like the name ...... Sky Muster, it taps into the rich heritage of the Australian cattlemen and women, stockmen, jilleroos, even the Banjo Patterson text "Man from Snowy River". Its all about rustling up some more broadband and access for the people of rural Australia and lifting the capability of rural Australia. Some people would see living remotely as advantageous, peace and quiet, the great outdoors, but the tyranny of distance has always meant is much harder to provide services - and today services means data access.

So I love the name, its certainly better that the Argentinian satellite on the same flight, Arsat-2 (just making sure I spelt that right .... yes I did) ;-)

Sky Muster or otherwise known as Satellite NBN1A was launched on Sept 30th on an Ariane 5 flight VA226 and took up its spot as a Geo-Stationary communications satellite designed to bring high speed broadband to Rural Australia.

There is a great animation here of the launch vehicles and satellites from the KNews team in Germany......

Well this is as close as Australia has to a Space Program at the moment, (in fairness we do lots of cool stuff from the ground).

I saw a note earlier that the satellite had successfully deployed it's solar panels and was healthy and well, so I thought I take a photo of it to celebrate. So, logging into the Internet of Everything (IoE), and using a remote telescope at Siding Spring Observatory I was able to grab a few shots of it and a few of its neighbors.

In the early part of the evening after the sun has set and the satellite is still in the sunlight (as its 36,000 Klms up) it is possible to grab some photos with a powerful telescope, kind of like photographing a bus from 36,000 Klms - difficult, but it can be done!

Those large solar panels are giving of a bit of reflected light and brighter than the Russian Express-AM5 which is 400Kgs heavier. You can also just faintly make out the Himawari 8 and the much smaller Beidou Chinese Sat-Nav satellite as well. You can also see another (non-geostationary) comms satellite cutting across the image as well.

The images are 60sec exposures from a Takahashi FSQ Petzval 106mm refractor telescope with a large field of view. The background stars look still and the movement of the geostationary satellite of course reflects the speed of rotation of the earth. They are hooting along quite quickly.

I trust the cattlemen, shepherds, wheat farmers and all rural folks get great use out of this investment in Sky Muster - I just had to take a photo of it. Congrats again Andy and all the NBN team.

Friday, October 9, 2015

Media "crying wolf" about Asteroid (86666) 2000 FL10 !

No, this is not a "surprise", has not been "just announced", is not a "near miss", is not a "shock". [Update 14th Oct: 2015 TB145 might have been worthy of that title but not 86666] However it is interesting due to its size ...... so lets have a sensible discussion.

As someone who is corporately qualified in Management of Risk (MoR) Framework, I fully appreciate the risk assessment process and freely admit to being constantly fascinated by applying this to my asteroid work. NASA and the other Space Agencies do this very well also. Last year at the Planetary Defence conference in Frascati, Italy, the key stakeholders in Asteroid research gathered for a conference that role-played an impending impact event, which everyone hopes will never be required. So there is a good deal of risk management going on.

So lets be controversial for a minute. Catastrophic climate change is a basket of risk that MUST include ALL the risks, not just the ones designed to shut down the coal industry. If a "continent cracking" asteroid were to hit earth, there would be alot of cranky people retrospectively assessing whether we spent too much on the wrong risk. In 2011, a 10m tsunami washed away a good portion of the coast of Japan triggered by one of the other big risks, catastrophic tectonic plate shift. An asteroid strike would create much more widespread damage and much larger tsunamis.

So how do asteroids fit in this risk picture and how did this all start?

In 1989, the asteroid now known as Ascelpius (4581) 1989 FC, occupied the same point in space that earth occupied 6 hours hours later, astronomers found this out 3 days AFTER it had passed. That was a close call! At 300m diameter it would have created enormous damage if it had hit. That was a surprise, that was a shock and immediate action followed. NASA/JPL began a 10 year mission to find 90% of all known asteroids by the end of the next decade. Whilst an awarness of the asteroid belt existed, after all (29075) 1950 DA was already a known risk and still occupies the number 1 position on the Sentry Risk table to this day. One of the major discoveries which was also unexpected was the amount of asteroids found in the range of 100m to 1Klm diameter. The Sentry Risk Table is now maintained by the NASA/JPL and tracks potential collisions there are 575 entries in the table.

Today there are 693000 known asteroids, 13000 of which are Near Earth Asteroids (NEAs), 17 of which have been discovered this month. So the risk is there, and after a decade of research, the scale of the risk had been under estimated.

Potentially hazardous asteroids (PHAs) are asteroids that come within 0.05 AU, or 5% of the earth-sun distance, and are greater than 100m diameter. The theoritcal "simple atmospheric physics" suggests that anything less than 80m diameter should "mostly" burn up in the atmosphere. However after the widespread damage caused by the Chelyabinsk Meteorite in Russia in 2013, which is thought to have been about 15-20m diameter, this threshold is now being re-assessed.

Its a fine line between education about risk, and overstating the risk of a particular event. Whilst each close pass can be used to build understanding of the risk and rally resources towards the efforts required to quantify the risk - its difficult.

Enter the modern media - recently distrupted by internet technology which fundamentally changed their engagement models and revenue streams. Often the journalists put up a sensational headline to get the click through to an article, which once you get past the headline, isn't quite so bad. This week we have seen a combination of these issues around Asteroid (86666) 2000 FL10. Now we also have the "Doomsday Preppers" and end of the world and conspiracy bloggers weighing in, with their own exaggerations and at times outright mis-information. What drives their interest in all this?

Escatological bible students have long been aware of a passage in Revelation of St John's vision of a "star falling from heaven and consuming a 1/3 of the land, sea and rivers", this star is given the name Wormwood. Learmonth Observatory has a Project Wormwood which is loosely derived from that text. However the leap to "number of his name (666)" later in Revelation and tying it to this asteroid, its beyond ridiculous, even for bible scholars. It is interesting however, that culturally, this is what drives the interest of "end-timers" and "doomsday preppers" in asteroids that come near the earth.

If only they could use their internet skills to actually help and track the asteroids through one of the many citizen science projects.

So that brings us back to "crying wolf". Asoep's famous fable (at least in western culture) about the shepherd boy who "cried wolf" when he got bored and wanted to see some action. The town's people would come running out to come and investigate and found no risk to the flock. After a while people began to ignore him and the inevitable happened, a real wolf showed up.

The questions the media should be asking:
1) what is being done to further research the apparent "cluster" of large asteroids coming inside the earth-moon distance [1 Lunar distance (LD)] between 2026 and 2030
2) What is being done to research the number of >300m near earth asteroids listed as "Lost"

There are many good things happening in asteroid research. Professional scientists are investing in new surveys, Panstarrs Survey is now fully operational. Amateur Astronomers regularly collaborate with professionals and do amazing follow up work. The gap in the southern sky above 30 degrees south declination left by the closure of the E12 Survey at Siding Spring has been picked up by, Panstarrs reaching further south, a repurposing of the WISE Space telescope, the Sonear Observatory in Brazil, the new ISON-South telescope, and the amateur astronomers who use iTelescope.net's Siding Spring Observatory telescopes.

So let's not cry wolf, let's educate and understand, let's progress our knowledge and support the effort to protect our home by getting positively involved. I am certain there will be more than one "end of the world" party on Friday April 13th 2029 when asteroid Apophis (2nd on the Sentry Risk Table) misses Earth by about 200 thousand kilometers and streaks across the sky as a naked eye object. You will be able to pull out the deck chair and pop the bubbly, safe in the knowledge that scientists that you funded have done the math, and you'll be able to relax and enjoy the spectacle.

http://www.jpl.nasa.gov/news/news.php?feature=4531

https://www.nasa.gov/content/asteroid-data-hunter-challenge-0

http://www.asteroidmission.org/get-involved/target-asteroids/

Monday, August 24, 2015

Australian Science Week - its a wrap!

Science week this year went to a whole new level in Australia. Following the lead from Prof Ian Chubb's STEM Strategy white paper, people really rolled their sleeves up and exceeded all expectations - and claimed two world records!

On Aug 12th, I was in Canberra for work and snuck out in the evening to catch the Science in the Pub sponsored by the ANU and the Australian - American co-operation through the US Embassy. The session was led by Prof Brian Schmidt (ANU), Dr Alan Duffy (Swinburne) and Glen Nagle (CSIRO/ANTF). An amazing session debriefing all the latest data from the NASA New Horizons, Pluto mission. If you had told planetary scientists only 6 weeks ago there was frozen nitrogen glaciers filling in old craters on Pluto, it would have been beyond their wildest dreams, yet that is exactly what they have found.

Friday 21st Aug The ANU/RSAA Stargazing night smashed two world record's for single-site and multiple-site observers with telescopes observing the night sky for 10 consecutive minutes. We were all a bit nervous about the weather, but the clouds cleared out just in time to ensure the night was a great success and everyone had a great time observing some fantastic sights through the larger telescopes. 76 people from the school community and nearby residents came out for one of the many local Melbourne sites at Norwood Secondary College in Ringwood. My trusty 14inch dobbie (dobsonian) was a hit, with people stunned and amazed looking at individual craters on the moons and counting the moons of Saturn which could be seen beyond the glare of the magnificent rings.

Mt Stromlo observatory in Canberra smashed the single-site Guinness Book of Record with a massive turnout of 1800 observers. The tally for the multi-site is still being finalized but was believed to have been over 10,000 people around the country. Once official it should easily eclipse the previous record of 3006 set in April 2013 in Mexico. Go Aussie!

Saturday 22nd Aug was a great night as well. The Scienceworks' Festival of Astronomy and Light opened up Scienceworks into the evening and I took the dobbie along again as one of the astronomers providing telescopes for viewing by the general public. Its amazing to watch kids who have never seen a telescope before walk up to one and try and work out which end/lens/mirror to look through. All are completely amazed at whats going on with all the lens and mirrors and when they see a crater on the moon as big as Tasmania it just blows them away. I have often described Astronomy as the "cupid's arrow of science", because of the emotional impact on people the first time they see the rings of Saturn or the craters of the moon. [That's original you have to quote me ;-) ]

As a veteran of many starparties it takes a bit to impress me, however I was not to be disappointed ........ a WORKING Tile from the Murchison Array had me fan-boying with selfies. It was sitting there on the grass collecting signals from the universe quite happily. Some 128 of these tiles currently form the Murchison Array, and will be a key part of the Square Kilometer Array that will put Australia at the forefront Astronomy research. If your dream is to win the nobel prize for Astrophysicis - Get into astronomy, go to the ANU or Curtain Uni in WA, and get onto the SKA (once built) and start data mining!!!!

Image: Selfie with "Popup Radio Telescope" - one tile of the Murchison Array actually working at Scienceworks.

What better way to wind up the week on 23rd Aug with some actual science supporting NASA's OSIRIS-REx Mission working with University of Arizona's Citizen Science Project - Target Asteroids. Laneway Learning, a novel idea that started as a way to increase traffic to a little coffee shop called the Little Mule Cafe (in a dead end laneway), has now gone global due to its outstanding success. Laneway Learning run eccentric little classes on just about anything to promote community engagement and sharing of ideas. I have run three "Asteroid Hunting" classes and become a regular at their Sunday Science Spectacular during Science Week.

Over a couple of hours about 10-20 people helped classify and record the photometry of asteroid Magellan, an analog of asteroid Bennu, the target of the 2018 OSIRIS-REx NASA New Horizons Mission. Asteroid Bennu is a carbonaceous asteroid and 3rd on the Sentry Risk Table that requires careful watching by amateur and professional astronomers alike. Bennu is a 492m asteroid that (at this stage) will pass at about 1/3 the distance to the moon in 2182. Saving the lives of your great grandchildren on a Sunday afternoon during science week - what could be better than that!

This is a photo of my little booth at Captain Melville's for the Sunday Science Spectacular.

All in all a great effort, thanks to Norwwod Secondary College, Mount Burnett Observatory, Scienceworks, Captain Melville's and Laneway Learning for putting up with me enthusiastically waving my arms about and carting large telescopes, screens and computers around.

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