2005 YU55 passes inside 1 lunar-distance - Nov 8th 2011
Monday, November 7, 2011 at 7:23AM | Pete - Admin As you have no doubt heard, Asteroid 2005 YU55 will pass inside the orbit of the moon at about 85% of the distance to the moon.
Will it go close to the Moon? Not really, as it will cross earth's orbit at a distance almost as far above the orbital plane as it is distant from us along the plane.
Still, that is very close in Astronomical terms and no (known) object of this size will pass this close again for another 17 years - 2001 WN5, which is a whopper at about 1 Klm wide, will come through at bout 0.7 LD (Lunar Distance) in June 2028. Then in 2029, Apophis makes its really close pass on April 13th, which I really hope isn't a Friday, but the path is well known with very low uncertainty and it too will pass safely by. So this is a very exciting event and will receive lots of coverage, with great opportunities to grab great photos and create videos.
On the evening of Nov 8, 2005 YU55 will approach from the daylight and will whiz across into the night sky travelling at a cracking pace up to 540 Arc secs per minute. So on the evening of the 8th it presents a challenging target. If you have a field of view of 4008 x 2675 Pixels at say 1 arc sec per pixel, you'll need about 4 "spot on" 20-30 sec frames to grab it......or you can wait for a few days until it slows down.
So some coaching might be in order here.
There are two ways to attack this:
1) Goto the position it will be "at an EXACT time" and camp on that position, and wait for it to fly through your photos.
2) Use the one line element to track on the actual asteroid as per the "Track Comet/NEO" approach on GRAS telescope interface.
The one line element will look like this:
K05Y55U 21.9 0.15 K118R 348.84963 268.77407 39.31601 0.51346 0.4289481 0.80685648 1.1427166 0 MPO196642 767 2 2005-2010 0.44 M-v 3Eh MPC 0000 2005 YU55 20100421
NOTE: DO NOT copy the above as even though the Asteroid is not visible until the 8th, the Arecibo and Goldstone Radar Radio Telescopes are already tracking it and have updated the orbit elements already. ALSO the above code is specific to H06 (New Mexico) observatory code, so it is only usable at that location. You should go to the MPC and the latest elements for your session. Note: some astronomy planetarium programs may not give you the best position, as unless they have the latest elements for the correct Epoch then you may run into some problems, this is less likely to be a problem, due to the high certainty of the orbit. [This was a problem for 2011 MD as it was inside the Hillsphere and was changing direction on an hourly basis]. As a rule I always get the latest data from the MPC.
If you go to the MPC
http://www.minorplanetcenter.org/iau/MPEph/MPEph.html
Click on "Minor planet epheremis" enter object "2005 YU55", click on "hourly" or "minutes" (not daily), and the enter observatory code of the telescope (NMS H06, Nerpio I89... etc or your own LAT/Long if you are doing this from your own scope at a different location).
If you want the exact co-ordinates hit enter, if you want the one line element then also select "MPC one line element" at the bottom.
You will have all you need.
So for Step 1) [Above] you enter the exact co-ordinates into the "Plan Generator" on the GRAS telescope interface, select your image duration etc. Save your plan. Then set up a "Launch a plan" reservation with a target of your co-ordinates and set up the start time to be 15 minutes before your target position, to allow the telescope to get through its focus run and shoot a couple of frames before it arrives. Note: the reservation tool works in local time whereas your Ephemeris generated by MPC will be in UTC. So you will need to account for this. If you get it right the Asteroid should fly on through your image right on queue. (Later in the week after the 10th this won't be quite so critical and you can revert to hourly positions, as it will then only be going <10 arc sec per minute) which means it will take some hours to cross your image field of view.
In the MPC Ephemeris printout the most cool feature is that it will tell you how far above the horizon the Asteroid is for your location......so you should target something reasonable Target ALT= >+35 degrees. It the ALT is minus its below the horizion, the the Sun ALT is + its day time ;-).
For Step 2) [Above] Once you have the One line element, making sure the Asteroid is above the horizon, on the GRAS Observation Plan, select "NEO/Comet" and you can paste the One line element straight into the Target box, select any other parameters like platesolving, etc. Once you start the run the Telscope will slew to the position and track the asteroid. (in this instance the asteroid will appear as a dot and the background stars will trail)
From Nov 8-9 it will be mag 11-13 so a 30 sec image will be fine, after the 10th about mag 14+ you would best go with a 60-120 sec image. (you might want to go a little longer on the smaller scopes)
If you are competent in Photometry you can participate in an observing campaign (Brian Warner is leading it) but that doesn't start till after the 10th when 2005 YU55 slows to a reasonable pace. (relatively.......it just keeps going but relative to earth its moving across the sky slower)
The MPC (Minor Planet Center) also has an observation guide page on it
http://www.minorplanet.info/ObsGuides/YU55/
This is a great opportunity, and you can amaze your friends with your telescope skills, this is a very exciting event and everyone will be talking about it by Friday/Saturday.
Enjoy, I hope you find the above helpful.
