Near-Earth Asteroid 2012 DA14 - 16 Feb 2013 (Singapore time)

Alright, this is for sharing of your observation experience. Or, if you are arranging gatherings, star-gazing expeditions or just want some company to go observing together, you can shout it out here.
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jiahao1986
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Re: Near-Earth Asteroid 2012 DA14 - 16 Feb 2013 (Singapore t

Post by jiahao1986 » Sat Feb 16, 2013 5:40 pm

As mentioned Gavin, Clifford, Zongyao and I successfully observed the asteroid flyby both visually and photographically. Thanks to Gavin's LX90 scope's accurate GOTO function and NASA's accurate coordinate data, we managed to grab a first view of the space rock at around 2:30am.

After that it became something like a hide-n-seek game with the clouds. However, there were enough breaks in the clouds for us to recover the target a few times after previously lost in clouds. Through Gavin's LX90, the asteroid looked bright and moved in a crazy speed! It swept across the field of view within 20s! At around 3:30 when the asteroid was moving towards the zenith at its fastest, I managed to catch it through my 10x50 bino using averted vision. The movement even in the bino was obvious too, very shocking experience since it's an asteroid, not an everyday artificial satellite!

Photographically it was frustrating due to fast changing cloud cover, however both Gavin and I managed to capture the scene through different devices when a big hole in the cloud drifted to the tail of Leo at around 4am. Gavin's picture can be found in the previous posts. Below is my shot with Canon 5D Mkii + 50/1.4 lens, at f/4, ISO800, 30 10-second tracked single exposures stacked. The start and end times are marked:

Image

And below is a 100% crop GIF animation showing the fast movement within 5 minutes. Note that even the 10 second single exposures get heavy trailing on the object already:

Image

And lastly the group photo. It was a tough-man-job thanks to the nasty weather. Kudos to the asteroid warriors! See you next time 2012 DA14!

Image

Clear skies,
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Clear skies please...

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Re: Near-Earth Asteroid 2012 DA14 - 16 Feb 2013 (Singapore t

Post by Gary » Sat Feb 16, 2013 5:41 pm

Nice report and photos Jia Hao! Thanks for sharing!
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Re: Near-Earth Asteroid 2012 DA14 - 16 Feb 2013 (Singapore t

Post by jimmyleong » Sun Feb 17, 2013 9:02 am

thanks for sharing...

must be a tough night.

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Re: Near-Earth Asteroid 2012 DA14 - 16 Feb 2013 (Singapore t

Post by starfinder » Sun Feb 17, 2013 9:02 pm

Great photos, Jia Hao! I especially like the animated gif.

As stated earlier, I will now add a few more details about our observing experience of Asteroid 2012 DA14's fly-by of Earth (on 15 February 2013 UTC time / Sat 16 February 2013 Singapore time):

- How did Asteroid 2012 DA14 look like in the eyepiece? Well, to me it appeared just as a pin-point white dot, similar in appearance to a star of equivalent magnitude. I could not detect any size or shape to the object whether at 143x or 300x. This is unlike, for example, the main moons of Jupiter which are seen as a distended disc at high powers, esp with larger scopes. Colour-wise, the asteroid appeared as plain white or grey, with no trace or hint of a hue. That was different from many man-made satellites seen with the unaided eye or through the scope, which appear yellowish.

- The brightness of the asteroid changed a lot in the span of that 3 hours. We first saw it in the eyepiece of my LX-90 at around 2.05am (which I recorded as the time of first sighting) when it was at a southerly declination of -62 deg in Centaurus, to the right of Acrux, with an elevation of 25 degrees above the southern horizon and mired in thin cloud cover. At that time, it was at around mag 9, quite faint but readily viewable with direct vision. The moment of first sighting was quite exhilarating!

Later on, when it was near the point of closest approach at 3:24am in Crater (near the border with Leo and Virgo), it was obviously much brighter and contrasty at around mag 6+; that part of the sky was also clearer for the most part. It was then at an elevation of around 80 degrees, almost overhead of us (it was then overflying nearby Sumatra). I managed to view the asteroid into 3:24am, but a few seconds later it dimmed out and was no longer seen; I think it was due to cloud cover rather than the asteroid entering into Earth's shadow. It was at this time that it also moved fastest, crossing the whole field of view of the 14mm eyepiece in 27 seconds.

When we last saw the asteroid at around 4:50am, it had very noticeably dimmed a lot, and was moving at a much slower rate. By then, the asteroid was in the north at declination +50 deg and in Ursa Major (near the Big Dipper), and at an elevation of 34 deg above the northern horizon.

Therefore, in that roughly 2 hours and 45 mins, we saw the asteroid traverse through around 112 degrees of declination (-62 dec to +50 dec): only in the tropics! Now that's a really fast moving natural object still in orbit around the Sun!


- As stated before, we had to constantly use the arrow keys on the Autostar handbox to keep the asteroid in the field of view of the eyepiece, even though the telescope was then doing its normal tracking at sidereal rate. It was like playing some computer game, called "Follow the Asteroid". I set the speed on the Autostar to number 4 (16x sidereal), which was ideal. Whenever anyone was about to let another person take over viewing the asteroid, he had to place it at the edge of the field of view, so that it would be somewhere near the center when the other person took over the viewing and the controls. I think Zong Hao was the most heroic, having once followed the asteroid for around 10 mins as it jumped in and out of clouds. I think I managed a 5 min continuous stretch of viewing.

- It was also quite intriguing watching the asteroid head towards some stars in the eyepiece. I had hoped to see an actual occultation, but the closest I saw was the asteroid whisking by a star at a "close approach" of around 1 arc sec. I think Jia Hao saw an occultation, not sure. I had earlier hand-plotted the path of the asteroid on my Sky & Telescope Pocket Star Atlas and identified some bright star occultation candidates. Unfortunately, the cloud cover was too variable, and the process of bringing the asteroid into the field of view too time-consuming, for me to follow up on that.

- The process of locating the asteroid was as follows: I had earlier generated minute-by-minute celestial coordinates of the asteroid using the NASA JPL Horizons interface (http://ssd.jpl.nasa.gov/horizons.cgi), set for our precise viewing location at East Coast Park, and stored it as a .txt file on my Android phone. I had generated an updated set of coordinates just a few hours before the viewing sesson. When we wanted to view the asteroid, I would use an atomic-clock app to ascertain the correct present time, e.g. 3:05am. Then I would key in the asteroid's coordinates for about 3-5 mins later, e.g. 3:08am. The Autostar would then point the scope at a nearby star for a "High Precision" centering in the eyepiece; once done it would then slew to the keyed-in coordinates for the asteorid. We then awaited the asteroid's appearance in the eyepiece near the appointed time. And then, bingo! There it is, the asteroid entered into the field of view! This process worked about 8-10 times, and there was perhaps 1 or 2 failures for unknown reasons.

- To tell the truth, I had all-along prior to first spotting the asteroid harboured a slight doubt that NASA had done its calculations correctly, e.g. my moon-gravity effect question. If their calculations were wrong, then our region would be the region of impact, considering the asteroid's approach from the south for a closest approach over nearby Sumatra. So an impact into the Indian Ocean off western Australia, generating a huge tsunami, was considered a possibility. If it crashed into the South China Sea south of Singapore, then hopefully Batam island would shield our sea-side observing site!

I even said that if we saw the asteroid in the sky with unaided eyes getting very bright, then it was time to run for cover. Perhaps down into the MRT tunnels!

However, of course, as we viewed the asteroid in the eyepiece exactly where it was predicted to be, and no brighter too, I felt assurred that there would be no surprises. But what if it crashed into a satellite and got deflected off-course? Ooops.

Anyway, our observations proved to us that NASA's calculations and assumptions were correct, at least down to a few arc minutes.

- When we were viewing the asteroid, I think it was then under the influence of Earth's gravitational field (its orbit was then being perturbed by it) and was getting a significant slingshot-effect boost. As we bid the asteroid farewell at 4:50am, we felt quite safe as it was then heading away from Earth. See you asteroid 2012 DA14, and thanks for the show!

- Finally, I wish to pay tribute and express thanks to NASA-JPL for so kindly making their Horizons interface available to the public around the world. Our viewing would not have been quite possible without those precise coordinates, certainly not at 143x magnification! I also wish to pay tribute to my reliable 12 year old Meade LX-90 8" SCT for its very stable, accurate and precise goto capabilities. Another American product! Below is a photo of the scope taken that night at the field. I had bought and taken delivery of the new LX-90 (the "Classic" model) in January 2001, just a few months after the product launch.

- And right below is a .gif animation made with 7 frames taken through the telescope at prime focus (2000mm). Canon EOS 60D dSLR. Each frame at ISO 3200 and 5 seconds.

Image

Image

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Re: Near-Earth Asteroid 2012 DA14 - 16 Feb 2013 (Singapore t

Post by rcj » Mon Feb 18, 2013 2:50 pm

certainly enjoyed reading the reports Gavin, Jiahao and the asteriod crew! quite a change from the usual prose on the net. Well done on the research and detailed work!
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Re: Near-Earth Asteroid 2012 DA14 - 16 Feb 2013 (Singapore t

Post by rcj » Mon Feb 18, 2013 3:39 pm

Here's a link to an animation of DA14 nicely tracked by the bisque mount from the net.

http://www.virtualtelescope.eu/2013/02/ ... -sequence/

Understand that the data was also obtained from JPL as per the owner's site location (90km south of Rome).

Personally I think it is a feat for amateur asteroid tracking (and especially for DA14 peculiar orbit and fast speed), not a simple click and slew to object:

1) Both pointing and also the ability to adjust the accurate tracking rates in the control system many times a second as required for this object to be tracked like this.

2) Challenge in adjusting the rates in RA and DEC simultaneously at a pretty fast rate at least once every second and have the telescope actually respond at this level of tracking (in this case a CDK17).
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Re: Near-Earth Asteroid 2012 DA14 - 16 Feb 2013 (Singapore t

Post by cataclysm » Mon Feb 18, 2013 6:19 pm

rcj wrote:Here's a link to an animation of DA14 nicely tracked by the bisque mount from the net.

http://www.virtualtelescope.eu/2013/02/ ... -sequence/

Understand that the data was also obtained from JPL as per the owner's site location (90km south of Rome).

Personally I think it is a feat for amateur asteroid tracking (and especially for DA14 peculiar orbit and fast speed), not a simple click and slew to object:

1) Both pointing and also the ability to adjust the accurate tracking rates in the control system many times a second as required for this object to be tracked like this.

2) Challenge in adjusting the rates in RA and DEC simultaneously at a pretty fast rate at least once every second and have the telescope actually respond at this level of tracking (in this case a CDK17).
Wow! Looking at those trailed stars, it really gives you the sensation of speed, the ateroid is really moving at a phenomenal speed!

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Re: Near-Earth Asteroid 2012 DA14 - 16 Feb 2013 (Singapore t

Post by mymoon » Mon Feb 18, 2013 7:40 pm

The time lapsed gives the impression that is the shape of the asteroid when it is not

This video gives a truer picture.

Cheers

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Re: Near-Earth Asteroid 2012 DA14 - 16 Feb 2013 (Singapore t

Post by Airconvent » Mon Feb 18, 2013 9:04 pm

Wow...thanks for sharing guys. This must be the pre-cursor to the "bright" comets that will coming soon. And I can see Gavin's ole' LX90 having a rare outing! :)
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Re: Near-Earth Asteroid 2012 DA14 - 16 Feb 2013 (Singapore t

Post by Gary » Tue Feb 19, 2013 2:45 am

mymoon wrote:The time lapsed gives the impression that is the shape of the asteroid when it is not

This video gives a truer picture.

Cheers
Thanks for sharing the link! C14! Nice video!
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