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2012-DA14

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#1 cloudmagnet

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Posted 02 February 2013 - 08:19 AM

Any charts, tips for observing this object?

#2 WillCarney

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Posted 04 February 2013 - 12:00 PM

See the other thread here.

#3 Centaur

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Posted 07 February 2013 - 06:15 PM

Any charts, tips for observing this object?


For the two charts I created, visit my asteroids webpage: www.CurtRenz.com/asteroids

Observing tip: Leave Texas and visit the Indian Ocean region on February 15th.

#4 TVG

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Posted 11 February 2013 - 05:27 PM

Here is an observing chart from www.freestarcharts.com



Todd

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#5 Centaur

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Posted 11 February 2013 - 06:05 PM

Here is an observing chart...


Thanks, Todd, but that is only good for those of you observing from London. For such a close object, the parallax effect leads to quite different perspectives from varying locations on the surface of the Earth. From here in the US the view would be different. That's why I did not present an ephemeris or star chart on my comets webpage. Also, your London chart is for daytime in the US.

#6 TVG

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Posted 11 February 2013 - 06:31 PM

Aw man, here I thought I could just go out 5 hours earlier and see it. Thanks for the heads up, and saved time spent searching for something that is not there. What an aggravating night that could have been. :crazy:
So not visible at all from the U.S. or does someone know of a different chart?

Thanks Again,
Todd

#7 Centaur

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Posted 11 February 2013 - 06:47 PM

So not visible at all from the U.S. or does someone know of a different chart?


You’re welcome, Todd. See the answer I gave recommending Solex in answer to a similar question from Darren Drake on the second page of this related thread: http://www.cloudynig...earearthobje...

The short answer is that from North America we will see the asteroid during the evening north of the Big Dipper while dimmer than eleventh magnitude.

#8 drbyyz

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Posted 14 February 2013 - 10:30 AM

If you have SkySafari plus or pro on your phone/tablet they recently updated their physics engine on it so it should be fairly accurate. Just do a search for "2012 DA14" and it'll pop right up.

#9 RedLionNJ

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Posted 14 February 2013 - 08:12 PM

Or use Horizons or Guide or any other popular (accurate)means of generating an ephemeris based on your location on Earth's surface. If you're using a planetarium-type program, just make sure to download the latest elements from the MPC during the day on Friday...

Grant

#10 Darren Drake

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Posted 15 February 2013 - 06:12 PM

I would be using Skysafari pro tonight as I have been watching it's position in real time on my phone all day but am stuck working at the space center and by the time I get home it will be to late. I hope someone out there has a chance to see it tonight...

#11 Centaur

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Posted 15 February 2013 - 07:05 PM

Or use Horizons or Guide or any other popular (accurate)means of generating an ephemeris based on your location on Earth's surface. If you're using a planetarium-type program, just make sure to download the latest elements from the MPC during the day on Friday...


Normally osculating orbital elements are just fine as long as the epoch is fairly nearby. In the case of Asteroid 2012 DA14 these fail miserably today. They assume Kepler’s two-body orbits: Sun and asteroid. In this case, elements for the epoch at a certain hour are not good for the next hour. However, it is this method that most sources are using. It results in great inaccuracies today.

I’ve relied on the Solex astronomical numerical integration program. That program does give osculating elements for any chosen epoch, but the positions I posted in another thread of this forum did not invoke those elements. Instead I took the hourly positions from numerical integration which ignores the method of Kepler. It continuously takes perturbations into account by relying on Newton’s two more basic force equations of motion and gravitation.

#12 Darren Drake

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Posted 15 February 2013 - 08:59 PM

Curt,
Are you saying that skysafari pro is wrong or inexact?

#13 Centaur

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Posted 15 February 2013 - 09:03 PM

Are you saying that skysafari pro is wrong or inexact?


Darren, I'm not familiar with skysafari. You'll have to tell me whether it uses osculating orbital elements or numerical integration.

#14 Darren Drake

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Posted 15 February 2013 - 09:33 PM

Sorry I have no idea how to find that out. Anyone???

#15 Centaur

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Posted 15 February 2013 - 09:41 PM

Sorry I have no idea how to find that out. Anyone???


Most likely osculating orbital elements. Compare its output with the positions I supplied in the other thread that were derived from the numerical integration within Solex.

#16 Centaur

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Posted 15 February 2013 - 10:06 PM

...just make sure to download the latest elements from the MPC during the day on Friday...


I use JPL and MPC only for the magnitude parameters of a minor body, unless Solex does not have the body in its data base. I just now checked and both JPL and MPC are using 2013 APR 18 as the epoch for Asteroid 2012 DA14. The updated solution date (this afternoon for JPL) only indicates when the accuracy of the elements was improved; it is not the epoch date. The epoch date is the moment for which it is assumed that everything disappears from the universe except the Sun and the particular minor body. When seeking positions before or after the epoch, perturbations are ignored. In the case of Asteroid 2012 DA14, that would result in substantial inaccuracies today, even if its geocentric coordinates are converted to topocentric (location on Earth’s surface).

#17 Mark9473

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Posted 16 February 2013 - 02:30 AM

Sorry I have no idea how to find that out. Anyone???


Most likely osculating orbital elements. Compare its output with the positions I supplied in the other thread that were derived from the numerical integration within Solex.


There's a thread in the Vendors forum about a new recent release of SkySafari that did have the computational algorithms to give correct results for 2012 DA14.






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