Astroblog

NEO 3122 Florence as seen from Adelaide on 1 September at 23:24 when the asteroid is highest in the sky (similar views will be seen from other Australian locations at an equivalent local time. click to embiggen).

NEO 3122 Florence makes an historic approach to Earth in early September. This will be the closest this asteroid, named after reforming nurse Florence Nightingale has come since 1890.

While not a particularly close approach (September 1, 12:06 UT, 0.047 AU, around 18 Earth-Moon distances), this will be the closest a large NEO has come to Earth since this class of objects were first described.

With a diameter of about 4.3 km, Florence ranks fourth in diameter of those NEO's classified as potentially hazardous. It is also the brightest of the Large NEO's, brighter than 3200 Phaeton (the asteroid responsible for the Geminid meteor shower).

Printable black and white chart showing the track of 3122 Florence from the 28th on. The Asteroid passes from close to Grus the crane, through and southern skies passing through Capricornius and Delphinus then Cygnus (click to embiggen and print)

The asteroid will range from magnitude 9 up to around magnitude 8.7 then fading down to 10.

This means that the asteroid is potentially viewable in good binoculars (10x50's and up) under dark sky conditions.  However, the waxing Moon will make binocular detection harder closer to closest approach. It will remain easily visible in small telescopes even with the increasing moonlight.

Printable black and white chart  suitable for binoculars showing the track of 3122 Florence from the 1st, the large circle is the field of view of 10x50 binoculars, (click to embiggen and print)

Although the asteroid is effectively on a line between the bright stars Fomalhaut and Altair, Finding the asteroid can be a bit tricky without good maps.

On the 29th, the asteroid is 22" from Zeta (ζ) Capricorii, and so should be easy to spot. You will need to watch the stars around  Zeta for around 15 minutes to detect the movement of Florence.

On the 30 the brightening Florence is within 22' of 29 Capricorii (which forms a triangle with iota and theta Capricornii), again, watching for 10-15 minutes will detect the asteroid drifting. 

On the 31st the asteroid is between mu and beta Aquarii, but is not close to a useful guide star.

Printable black and white chart  suitable for telescope showing the track of 3122 Florence from the 1st, tthe large circle is the field of view of 10x50 binoculars, he small circle is the field of view of a 23 mm eyepiece and a 114 mm refractor.(click to embiggen and print)

On the first the asteroid is within binocular distance of alpha Equuleus, and between that and 1 Aquarii, but again is not near any obvious guide star. Still if you watch for 10-15 minutes you will see the asteroid drift against the background stars.

Many instruments will be watching this approach, including the Goldstone radar to try and capture its shape and possible satellites.

While not spectacular, this will be an historic pass to witness, the next closest approach of Florence is in 2057.

Labels: asteroids, binocular, NEO, telescope

NEO 2014 RC as seen from Siding Springs Observatory from 1:15 am 8 September - 5:15 am (15:15 - 19:15 UT 7 September). The crosses mark the position of the asteroid every 5 minutes. Positions calculated in Horizon Track from JPL horizons data. click to embiggen.

Near Earth Asteroid  2014 RC will  come close to Earth on 18:00 UT 7 September at distance of 0.0003 AU (around 0.15 Earth-Moon distances). It has an estimated diameter of  20m. It is brightest at 17:15 UT though.

The asteroid is currently magnitude 19, and will be a reasonably mag 11.2 at closest approach, despite its small size.

The asteroid is well placed for southern observers, and will be relatively bright (magnitude 13 to 11) from midnight on. Imaging this may be difficult as the asteooid is moving too fast to track. OIndeed you will need a widefield objective to see the asteroid falsh past at cloest approach around 3 am on Sunday. .

NEO 2014 RC as seen from Siding Springs Observatory from 2:50 am 8 September - 3:50 am (16:50 - 17:50 UT 7 September). The crosses mark the position of the asteroid every 5 minutes.

Positions calculated in Horizon Track from JPL horizons data. The circles mark the different location of the Asteroid im MPC (2014 RC) and JPL (2014 RA) data click to embiggen.

NEO 2014 RC  passes from Aquarius through Sculptor and Phoenix to Eriadanus.

The asteroid is visible from start of astronomical twilight in the evening of the 7 September local time (magnitude 14) until end of astronomical twilight on the 8th (local time).

You will need to use a topocentric ephemeris and camp out on the asteroid track.

There is a substantial parallax effect (gretaer than one defree 1 degree), so unless your planetarium program is able to cope with close parallax (most can't), you will need to work from topocentric coordinates. You will need your latitude and longitude for an accurate ephemeris from you position.

For topocentric ephemerides go to http://www.minorplanetcenter.net/iau/MPEph/MPEph.html

Always use the latest possible orbital elements and ephemeris.  The planning guides to viewing YU55 here and here will help organising topocentric ephemerides for close approaching NEO's.

You will need to use unguided exposures. Choose a point where the asteroid will pass and aim at that. 

Labels: asteroids, NEO

NEO 2007 PA8 as it came close to Earth on 5 November, this shows the view of the asteroid from Mayhill New Mexico when it transited at 4:02 am (click to embiggen).

NEO 2007 PA8 is a 2.4 Km long space rock that came within 16.8 Earth-Moon distances on November 5, 16:43 UT. Although it was a relatively bright object at magnitude 11.8, it was only 51 degrees from the waning Moon, and at it's highest it was only 27 degrees above the southern horizon as seen from Mayhill New Mexico, just above the lower limit of travel of those scopes.

The image is a stack of 5 x 120 second exposures using iTelescope T5 with no filter, aligned in ImageJ then stacked using the MAX Z-project function.  I erred far to far on the side of caution with my exposures, 60 or even 30 second exposures woul have worked well and given me a better track and animation.

There's been a whole bunch more NEO's discovered that zip past in the next day or so (more info tonight), so it will be a busy time for NEO imagers.

My animation is below.

Labels: asteroids, NEO

UPDATED! with charts based on the latest ephemeris. 

Labels: alert, asteroids, NEO, telescope

NEO 2012 LZ1 at 7:53 UT, nearly 9 hours after closest approach. 5x120 second Images taken with iTelescope T5. The images were stretched in FITSliberator, then stacked in ImageJ and a Max intensity Z project made, then despeckeled.	NEO 2012 LZ1 two hours later, zipping through star clouds. Processing as for the earlier image.

These look to be my final images of the NEO 2012 LZ1, taken with the New Mexico T5 instrument nearly 9 and 11 hours after the asteroids closest approach.This is a much narrower FOV instrument that T14 and T16. A big thank you to Jeff Woods of iTelescope who adjusted the travel of T5 so we could take earlier images.

I'll now do some astrometry on these images to help refine the asteroids orbit.

There is a nice article at Universe Today which features one of my images, and here's a nice animation by Peter Lake using iTelescope T11. My other shots and animations of this asteroid are here, here and here.

My animation here

Labels: animation, asteroids, FITSLiberator, imageJ, iTelescope

NEO 2015 TB145 at midnight on 31 October 2015, it is just above the shield of Orion. Click to embiggen.	NEO 2015 TB145 at astronomical twilight on 31 October 2015, it has moved towards the bottom of the shield of Orion. Click to embiggen.

Near Earth Asteroid 2015 TB145 with an  estimated diameter of around 460 m will come relatively close to Earth on 16:18 UT, 31 October (3:18 am 1 Nov AEDST) at distance of 0.003 AU (around 1.3 Earth-Moon distances, ie it is further away from us than the Moon, so there is no chance it will hit us). It is brightest at 12:30 UT on the 31st though (11:30 pm 31 Oct AEDST).

At this time the asteroid will be a reasonably bright magnitude 10.1, easily visible in small telescopes and strong astronomical binoculars. Unfortunately from Australia we will be unable to see it as it is in the northern hemisphere.

Black and white chart suitable for printing showing the track of the asteroid from midnight to sunrise and beyond on 31 October. The circle shows the field of view of 10x50 binoculars (although you will not be able to see it in binoculars, this simulates the FOV of a finder scope).

The asteroid is near Orion's Shield. Tick marks are an hour apart. Click to embiggen and print. Use the charts up above to orient yourself first.

NEO 2015 TB145 moves from Taurus to Orion, then back into Taurus (crossing the horns of the Bull), into Auriga (where it is brightest) then on to Lynx and beyond.

Australia's best  view is on the morning of the 31st, when the asteroid brightens from magnitude 13 to magnitude 12.5. It will be visible in amateur telescopes (as a faint dot), however, the still bright waning Moon 17 degrees away will make it a bit tricky to spot. Its movement should be obvious over several minutes in a medium power telescope eyepiece.



Black and white chart suitable for printing showing the track of the asteroid from midnight to sunrise and beyond on 31 October. This chart is suitable for telescopes. The chart is inverted with respect to the finder chart above.

The circle is the field of view of a 20 mm eyepiece with a Newtonian  reflector scope. Tick marks are 30 minutes apart. Click to embiggen and print. Use the binocular charts up above to orient yourself first

The asteroid is currently magnitude 19.5, and  will not really be accessible to modest amateur equipment until the 30th. You can get an accurate ephemeris for your location from the Minor Planet Ephemeris Centre or JPL horizons. It is best  to wait a few more days to generate an ephemeris as better position data is gathered.

Labels: alert, asteroids, NEO, telescope

NEO 2012 QG42 imaged using the iTelescope T5 instrument on 11 September 2012. This is a stack of 15 x 60 second images. The  stacked in ImageJ and a Max intensity Z project made, then despeckeled. The images  have variations in brightness which may indicate it is rotating.  Click to embiggen.

Near Earth Object 2012 QG42 is a recently discovered relatively bright NEO. It is a 375 metre diameter rock that will be 7.4 Earth-Moon distances from us at closest approach on September 14 at 05:08 UT.

Un-calibrated intensity of each asteroid image obtained using ImageJ. This suggests the asteroid is rotating rapidly.


As it comes closer to Earth it appears to be moving faster. For my previous images and animation (using 120 second exposures rather than the 60 seond ones here) see here.

Here's my video made from my image sequence.

Labels: animation, asteroids, iTelescope, NEO

Location of NEO 2012 QG42 at 9 pm local time on 13 September as simulated in Stellarium	Location of NEO 2012 QG42 at 9 pm local time on 14 September

375 metre diameter Near Earth Object 2012 QG42 will be 7.4 Earth-Moon distances from us at closest approach on September 14 at 05:08 UT (that 3 am AEST, but the asteroid will still be close after astronomical twilight in Australia).

 At magnitude 14 or so (ignore the Stellarium magnitudes, they are too dim) it will not be visible in binoculars or small telescopes, you will need a 6" or more scope and dark skies to see this. However, you will be able to see the asteroid visibly move over a period of a few minutes, so it's worth a look.

In Australia it's not far from the bright star Altair in Aquila, and is a good distance above the horizon at 7:30 pm local time (around astronomical twilight), and is probably too low to image by 11 pm.

Because it so so close to earth parallax is a problem, and Stellarium positions will be out. Links to detailed ephemeris's can be found here. My previous images of the asteroid are here, here and here.

Labels: asteroids, NEO, stellarium

NEO 2012 QG42 imaged using the iTelescope T5 instrument on 12 September 2012. This is a stack of 7 x 60 second images.

They were  stacked in ImageJ and a Max intensity Z project made, then despeckeled. The images  have variations in brightness which may indicate it is rotating (see my previous image for a better plot).  Click to embiggen.

375 metre diameter Near Earth Object 2012 QG42 continues to brighten as it heads for closest approach. It will be 7.4 Earth-Moon distances from us at closest approach on September 14 at 05:08 UT.


Un-calibrated intensity of each asteroid image obtained using ImageJ. This suggests the asteroid is rotating rapidly.





For my previous images and animation see here and here.

Here's my video made from my image sequence.

Labels: animation, asteroids, astrophotography, iTelescope, NEO

Close up of NEO asteroid 2012 OQ as it zooms past	Full field of view with IC5067, the asteroid is a bit difficult to see, but it is near the middle, click to embiggen, it's worth it

Asteroid 2012 OQ is a is a 195 m diameter rock that comes within 7.7 Earth-Moon distances of us. It is closest on July 24 at 18:23 UT (that's 4:23 am 25 July AEST). But it's also getting dim then.

I shot the asteroid using  iTelescope T5 earlier this evening when it was close to the nebula IC 5067. Sadly I lost over half of my images to drifting cloud, but I wasn't alone in this. Still, I think it came out rather well with the frames I did get (4x120 sec images stretched in  FITSliberator, stacked in ImageJ and despeckeled. While the asteroid is dimmer than 2012 LZ1 the nebula more than makes up for it.

Here's a slightly sad animation I made.

Labels: asteroids, iTelescope, NEO

2012 QG42 image using the iTelescope T5 instrument on 7 September 2012. This is a stack of 10 x 120 second images. The images were stretched in FITSliberator, then stacked in ImageJ and a Max intensity Z project made, then despeckeled. The Images seem to have variations in brightness which may indicate it is rotating. I'll have to take another set and do proper photometry on them. Click to embiggen.

Near Earth Object 2012 QG42 is a recently discovered relatively bright NEO. It is a 375 metre diameter rock that will be 7.4 Earth-Moon distances from us at closest approach on September 14 at 05:08 UT.

Here's my video made from my image sequence.



And here's Peter Lake's video sequence from the same night.

Labels: asteroids, iTelescope, NEO

NEO 2005 WK4 at 8:30 UT 8 August, the day before closest approach. 10x30 second images taken with iTelescope T5. The images were stacked in ImageJ and a Max intensity Z project made, then despeckeled and inverted.The sequence is gappy as cloud rendered some frames useless (I took 20 frames)	Animated gif from the 10 frames

Near Earth Asteroid 2005 WK4 will come close to Earth on August 9 at 05:02 UT at distance of 0.02 AU (around 8 Earth-Moon distances). It has an estimated diameter of 420 m. The asteroid is currently magnitude 15.5, it reaches mag 14.4 at closest approach then brightens to 14.0 as it moves away.

Labels: asteroids, NEO

Back in March I wrote a post “Occam's Razor and the Two World Systems”, where I discussed the idea propounded by William Wallace that Occam’s razor failed when applied to the transition from the Ptolemaic geocentric solar system to the Copernican heliocentric solar system. Mr Wallace replied on that post and I promised to respond, but life (and various asteroids and comets) got in the way. Rather than add new comments there. I’ll take this up as a new post.

The starting point of the old post was Mr Wallace’s contention:

I have a counter example, from science, fully described here, where Occam's razor fails. The idea that the "simplest explanation is probably right" was falsified when Tycho Bryhe [sic] rejected heliocentricism for geocentricism, based on his analysis of the best available data.

Once again, I must emphasise that Occam’s razor is not the simplest explanation is probably right, but let’s pick up on Mr. Wallace’s comments. I’m going to do this slightly out of order, so as to address particular issues that arise from the quotes more logically

There were three systems, Copernicus, classical Ptolemaic, and neo-Ptolemaic (or Tycho's). Both Ptolemy's and Tycho's could be accurately described as geocentricism. I just want to clarify that I don't think I ever claimed--and I certainly never intended to claim--that Tycho held a purely Ptolemaic view of the solar system. He held a geocentric view, more consistent with Ptolemy's than Copernicus's (though Kepler's was arguably more akin to Copernicus's than Tycho's was to Ptolemy's.)

This is so very, very wrong. Tycho’s system was not a neo-Ptolemaic system, as I describe below, Tycho explicitly rejected the Ptolemaic system based on observational evidence. Tycho accepted most of Copernicus’s system, but balked at a moveable Earth and produced a Heliocentric-geocentric system (not a geocentric system, for another animation of the respective systems see here). Indeed it is an “inverted Copernican” system, basically a remapping of the Copernican system into a reference frame centred on Earth. Tycho’s system contains nothing of Ptolemy; there are no equants, no great epicycles and so on[1]. I’ll emphasise that again, Tycho’s system was not a re-jigging of Ptolemy, it was an inversion of Copernicus’s system.

The only point of similarity between Ptolemy’s system and Tycho’s system was the Earth was immobile in both systems, but in Tycho’s, everything but the Moon rotated around the Sun. Again, the key features of Ptolemy’s system, the equant and the great epicycles were absent from Tycho’s formulation. This may seem like mere pettifoggery, after all, both Ptolemy and Tycho had the Earth as the centre of the solar system, but Ptolemy’s system was not just “everything goes around the Earth”. Tycho had explicitly rejected the Ptolemaic system, all the key features of the Ptolemaic system, taken all the planets and placed them around the Sun and grounded his system on a reformulation of the Copernican system.

Tycho's system required fewer calculations and was consistent with all known measurements. Copernicus's was not consistent with observations.

Tycho's system required roughly the same number of calculations as Copernicus’s, as it was basically Copernicus’s translated into Earths reference frame [2]. Tycho fully accepted Copernican geometry, used Copernican planetary models, and where he did not explicitly do his own calculations, he used planetary tables based on Copernican models. Where Tycho was more accurate than Copernicus, it was through his greater observational accuracy, not any superiority of his model. Indeed, when he talks of his system, he notes that he has kept all the superior features of the Copernican system. Ironically, it was Tycho’s own measurements of the opposition of Mars in 1582 that showed that the Copernican model was in better agreement with the observed retrograde motion of Mars than the Ptolemaic model.

And yet Copernicus' model defied experimental verification, using the best astronomical apparatus of the time (Tycho's).

Actually, that’s not true. There was a key test of the Ptolemic vs Copernican system and the Copernican system came through with flying colours. It was one of the key results that forced Tycho to reject the Ptolemaic system. However, that test tends to be ignored these days because of modern commentators focusing on the issue of stellar parallax.

We now know that stellar parallax could not be measured with instruments available then. It wasn’t obvious back then, and there were several attempts to measure the stellar parallax. Tycho established that the stellar parallax had to be less than 0.1 degree. However, this did not falsify the Copernican model as negligible parallax was an a priori feature of the Copernican system.

Tycho was well aware of this, and his argument was not that the lack of parallax showed that the Earth did not move, but that if the parallax was so small the distance between Saturn and the stellar sphere would have to be 700 times the distance between the Sun and Saturn. A provident creator would not be so wasteful of space and produce such asymmetry in his creation.
So we can see that the stellar parallax argument as used by Tycho is in the end not a scientific argument.

So what was the measurement that convinced Tycho to reject the Ptolemic system? Ironically, it was a parallax measurement. One of the predictions of the Copernican system was that Mars would be closer to Earth than the Sun at opposition; while in the Ptolemaic system Mars would always be more distant from the Sun. Tycho’s careful measurements of the parallax of Mars showed that Mars was closer to Earth than the Sun. Similar measurement of Venus’s parallax by Tycho also confirmed Copernican predictions. Copernicus was right, Ptolemy was wrong, and Tycho unhesitatingly rejects Ptolemy. But in the end Tycho rejects both Ptolemy and Copernicus.

My ultimate point about Tycho's rejection of Copernican theory was that applying principles of modern science sometimes leads one astray.

Erm. Mr. Wallace. This is what you said:

I have a counter example, from science, fully described here, where Occam's razor fails...

In this case, it was Tycho’s system failed the Occam’s razor test. It requires more assumptions than the Copernican system, introduces two centres of motion, introduces more problems with motions and whilst reproduces the retrograde motions of the planets, it no longer provides these motions as a natural consequence of the orbits of the planets. Altogether it is far less economical than the Copernican system and no longer explains the precession of the equinoxes and is affected by solar eccentricity (and this was pointed out at the time). Occam’s razor doesn’t fail, because Occam’s razor was not used to make the choice between the Copernican and Tychonian systems. What was the basis of Tycho’s rejection of the Copernican system? Let Tycho tell us in his own (translated) words.

Since all these results [parallax measurements of Mars and Venus] did not all agree with the Ptolemaic hypotheses I was urged afterward to put more and more confidence in the Copernican invention. The exceedingly absurd opinion that the Earth revolves uniformly and perpetually nevertheless made up a very great obstacle, and in addition the irrefutable authority of the Holy Scripture maintained the opposite view. [emphasis added]

It wasn’t the principles of modern science that lead Tycho astray.

[1] The equant was seen as a particular drawback to Ptolemy’s system, if one wanted to explain planetary motion in terms of uniform circular motion, and Copernicus reformulation of planetary motion so that the equant was dispensed with. This was seen by contemporary astronomers and mathermaticians and a great benefit of the system. Tycho too saw the equant as something undesirable, and the great epicycles of Ptolemy as unparsimonius.
[2] Tycho got rid of Librations, but generally his scheme was Copernicus’s recast from Earth’s frame of reference.
[3] Ironically, Tycho’s system made the acceptance of the Copernican system easier. It made people familiar with the Copernican system, and smashed key sections of Aristotelian physics which have proved a barrier to acceptance of he Copernican system.

Sources:
The Reception of Copernicus’s Heliocentric Theory 1973 ed Jerzy Dobryzcki, Reidle esp Chapter 3.
Copernicus, On the Revolution of the Heavenly Spheres (translation AM Duncan 1976) Barnes & Nobel
The Copernican Revolution 1957, TS Kuhn Harvard University Press
The Book Nobody Read 2004, O Gingerich, Walker & Company

Labels: Copernicus, creationism, Galileo

NEO 2005 WK4 at 8:30 UT 9 August, 3 and a half hours after closest approach. 6x15 second images taken with iTelescope T5. The images were stacked in ImageJ and a Max intensity Z project made, then despeckeled and inverted.The sequence is very gappy, like my last sequence, as cloud rendered most frames useless (I took 20 frames)	Animated gif from the 6 frames

Near Earth Asteroid 2005 WK4 came close to Earth on August 9 at 05:02 UT at distance of 0.02 AU (around 8 Earth-Moon distances). It has an estimated diameter of 420 m. The asteroid is currently magnitude 14.4 then brightens to 14.0 as it moves away.My previous images are here.

Labels: asteroids, iTelescope, NEO

The position of asteroid 2004 BL68 as seen at 22:00 ACDST on the evening of 26 January 2015 from Adelaide. Similar views will be seen at 22:30 AEDST and 21:30 AEST. Click to embiggen	Approximate binocular view of asteroid 2004 BL68 as seen at 22:00 and 23:00 ACDST on the evening of 26 January 2015 from Adelaide. Similar views will be seen at 22:30  and 23:30 AEDST and 21:30- 22:30  AEST. Click to embiggen

In my previous article on 2004 BL86 I explained in detail how to see this NEO at its brightest ... at around 4:30 am in the morning when it is close to the bright open cluster M48. For those of you who want to see it on the night of the 26th, before heading to bed, I've created these instructions.

You will need a telescope, not a fancy one, but a telescope none the less. Finding the asteroid will be harder as it is dimmer, and there is no obvious bright feature to use as a guide. But while harder it is well worth the effort.

Printable black and white horizon chart facing east an hour and a half after sunset on the 26th showing the location of 2004 BL86 as seen from Adelaide. Similar views will be seen from East coast and central locations at the equivalent local time. WA sees the asteroid further along in its path. Click to embiggen and print

Printable black and white binocular chart  showing the location of 2004 BL86 at 22:00 to midnight  ACDST on the evening of 26 January 2015 from Adelaide. Similar views will be seen from 22:30 AEDST and 21:30 AEST. The large circle is approximately the field of view of 10x50 binoculars. The small circle the approximate field of view of a 25 mm eyepiece with a 114 mm Newtonian telescope. Click to embiggen and print.

To find the asteroid, again we will use bright stars as a landmark. If you draw a line between Jupiter and Canopus (the brightest  and third brightest objects in the sky at this time), then draw a line perpendicular from Sirius (the second brightest object in that part of the sky) to the Jupiter - Canopus line, the intersection is where the asteroid will be.

In binoculars or a telescopes finder scope you will see a triangle of stars. The faint star at the apex of the triangle is 11 Pupis. The asteroid zooms past this star as seen from the eastern and central states. From WA, by the time the sky is darkenough, the asteroid is well below 11 Puppis, but you can use the charts to sweep down and find it.

Printable black and white binocular chart  showing the location of 2004 BL86 at 22:00 to midnight  ACDST on the evening of 26 January 2015 from Adelaide. The circle the approximate field of view of a 25 mm eyepiece with a 114 mm Newtonian telescope. The orientation is upside down from the binocular map as telescopes invert the image. Click to embiggen and print.

 With your telescope a wide field eye piece, first centre 11 Pupis in the eyepiece, then move it so 11 Puppis is at the western edge of the eyepiece. The asteroid should be visible as a faint dot on the western side, moving slowly but inexorably across the stars.

The printable charts above will be needed help you find the asteroid.Remember, when looking for the asteroid allow at least 5 minutes or more (10 is better) for your eyes to adjust and become dark adapted. Here's some hints on dark adaption of your eyes. If using the charts above, cover your torch with red cellophane so as to not destroy your night vision.

Labels: asteroids, NEO, telescope

NEO 2005 WK4 at 18:00 UT 10 August, 13  hours after closest approach. 19x15 second images taken with iTelescope T9. The images were stacked in ImageJ and a Max intensity Z project made, then despeckeled.The sequence is an improvement on the previous attempts that were	Animated gif from the 19 frames

Near Earth Asteroid 2005 WK4 (420 m diameter came close to Earth on August 9 at 05:02 UT at distance of 0.02 AU (around 8 Earth-Moon distances). The asteroid was around currently magnitude 14.0 when I took this.My previous images are here and here.

Here's a YouTube version of the animation as well

Labels: asteroids, iTelescope, NEO

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).

Labels: asteroids, binocular, iTelescope, NEO

2013 QR1, (large dark streak) and two possible companions (or internal reflections). Imaged with iTelescope T12, 11 frames of which only 8 had 2013 QR1 in them (it was moving really fast), the two other traces continued when 2013 QR1 was out of frame, and the middle trace overtook the upper trace, so I don't think they are internal scope reflections. Click to embiggen to see the two faint traces clearly.

Animation of 8 frames with 2013 QR1 in the field. In the small version here you can just see the brighter of the two companions, if you click on the image and embiggen it, the third companion is visible if you squint (unless you really want a 25 Mb animation file it's not that clear)

NEO 2013 QR1 made a close approach to Earth on August 25, 19:31 UT. The 215 meter diameter rock came within 9 Earth - Moon distances. The Asteroid was moving at greater than 100"/ second, was around magnitude 15.5.

Unfortunately, the closest approach was out of reach of the iTelescopes, but I got it in the SSO scopes around 3 hours later.

I got a bit more than I bargained for though. Along with 2013 QR1 were two other fainter, fast movers. I don't know yet if they are known asteroids, or unknown asteroids, or even satellites. But I'll try and get them again tomorrow (the middle one probably not, it was moving faster than the other two and will probably be far way by tomorrow night).

I have no idea of how to do astrometry when the traces are streaks, so I don't know how to trace it back through existing MPC orbits. Anyone have any ideas?

Labels: asteroids, iTelescope, NEO

The position of asteroid 2004 BL68 as seen at astronomical twilight on the morning of 27 January 2015 (4:50 am ACDST, one and a half hours after sunset) from Adelaide. Click to embiggen	The position of asteroid 2004 BL68 as seen at astronomical twilight on the morning of 27 January 2015 (4:50 am ACDST, one and a half hours after sunset) from Adelaide. Click to embiggen
Printable black and white horizon chart facing west an hour and a half before sunrise on the 27th showing the location of 2004 BL86 as seen from Adelaide. Similar views will be seen from Southern Hemisphere locations at the equivalent local time. Click to embiggen and print	Printable black and white binocular chart an hour and a half before sunrise on the 27thshowing the location of 2004 BL86. The large circle is approximately the field of view of 10x50 binoculars. The small circle the approximate filed of view of a 25 mm eyepiece with a 114 mm Newtonian telescope. Click to embiggen and print

Near Earth Asteroid  2004 BL68 will  come close to Earth on 16:20 UT 26 January at distance of 0.008 AU (around 3.1 Earth-Moon distances). It is brightest at 04:00 UT on the 27th though. It has an estimated diameter of 680m (a bit over half a kilometer). The asteroid will be a reasonably bright magnitude 9.0 at closest approach, and it comes close to the iconic Beehive cluster when it is still bright.

The flyby of 2004 BL86 will be the closest by any known asteroid of this size until 2027 when asteroid 1999 AN10 goes past Earth. It is also the brightest since 2012 DA14 in 2013.

Unfortunately, from Australia the asteroid is below the horizon at its brightest. We get to see it when it is between magnitudes 10-9.6. The theshold for unaided eye viewing is magnitude 6, so the asteroid is quite dim. Australians can see the asteroid move from Puppis (on the late evening of the 26th, Australia day) through Monocerous and into Hydras.

While the asteroid can be picked up by high end binoculars under dark sky conditions, for most observers small telescopes will be required. My small 114 mm Newtonian with a 25 mm eyepiece allows me to see stars dimmer than magnitude 10.

The printable charts above will also help you find the asteroid. For telescope users, the image will be upside down compared to the charts (so hold the binocular/telescope chart upside down). Remember, when looking for the asteroid allow at least 5 minutes or more (10 is better) for your eyes to adjust and become dark adapted. Here's some hints on dark adaption of your eyes. If using the charts above, cover your torch with red cellophane so as to not destroy your night vision.

When looking for the asteroid in the early morning, we have a good signpost and viewing opportunity. The asteroid comes close to (eastern states) and crosses (western and central states) the relatively bright (magnitude 5.8) open cluster M48 before astronomical twilight. If you find the open cluster then you can camp out on it and watch the asteroid creep towards it.

You can find the cluster fairly easily. If you draw a line between Jupiter and Sirrius (the two brightest objects in the sky at this time), then draw a line perpendicular from procyon (the third brightest object in that part of the sky) to the Jupiter - Sirius line, you should be able to (just see) M48. It will be quite obvious in binoculars or a telescopes finder scope.

With the cluster in view, sweep slowly south around half a field of view at a time. The asteroid may be initially difficult to distinguish as a fairly dim dot, even in a telescope, but it is the only dimmish dot moving slowly and relentlessly towards the cluster.  It may take half an hour to cross the field of view of a wide field eye-piece, but it's motion is fast enough to pick it up.

For central states the asteroid crosses the cluster from around 4:40 to 4:50 am ACDST (3:40-3:50 ACST), for Western Australia the asteroid crosses M48 between roughly 2:10 am - 2:20 am AWST (it is much higher in the sky, so easier to pick up in WA). In the eastern states the asteroid is two cluster widths away from M48 at astronomical twilight (roughly 3:48 am AEST and 4:36 am AEDST).

For those of you familiar with charts and ephemerides, you can generate your own ephemeris using the MPEC ephemeris generator. http://www.minorplanetcenter.net/iau/MPEph/MPEph.html

Use your longitude and latitude for an ephemeris for your location, remember the times are in UT adn it is best to choose and observing interval of around 15 minutes as the asteroid is moving relatively quickly.

Here's some NEO's I've captured in the past.

Labels: asteroids, NEO, telescope

Asteroid 1998 QE2, 28 May, 12x10 second exposures stacked in ImageJ and MAX Z-project applied. R filter, iTelescope T9 (it's the bright point like object, the stars are trailed as the scope tracks on the asteroid).	Animated GIF from the 12 frames
Evening sky as seen looking north from the Siding Springs Observatory at 11 pm AEST (similar views will be seen elsewhere at an equivalent time)	Close up view of the track of 1998 QE2. The tick marks are every 3 hours, closest approach is at 4:59 AEST June 1.

Near Earth Object 285263 1998 QE2 will be of interest for the those with modest sized telescopes and up. This is a "bright" (bit better than magnitude 11),  relatively slow mover, visible from all of Australia (and the world) and you don't have to do much fancy foot work to catch it as it passes through Libra.

285263 1998 QE2 is a whopping 2.1 Km diameter rock that will be 15.2 Earth-Moon distances from us at closest approach.

It is closest on May 31 at 20:59 UT. That's 4:59 AEST June 1 in Australia. But it is pretty bright before this (magnitude 10.8), and is actually slightly brighter after this (magnitude 10.7 for a couple of days). From Australia it is quite high in the sky, and passes some reasonably obvious sky landmarks, so is easy to find. Also, it is moving fast enough that after a relatively short while you can see it move with respect to the background stars.

Standard planetarium plotting will work well, if your planetarium program can import orbital elements. Unfortunately Stellarium chokes on NEO orbits, even 1998 QE2, which is relatively far away, so you have to use something else. You can also create an ephemeris directly from the Minor Planet Center. For MPC ephemerides or downloadable orbital elements go to
http://www.minorplanetcenter.net/iau/MPEph/MPEph.html

Here's my GIF animation as a Youtube video http://youtu.be/tCY2Cl8eaOQ

 Even better, here's Andrew Wall's widefield video from tonight  http://www.youtube.com/watch?v=faQsamr2-5c

Labels: asteroids, imageJ, iTelescope, NEO