A bit of a thread dig but better to put it here than start another.
When this asteroid passes by, understanding that both its orbit and ours will change, but ours by such a tiny amount to probably be not measurable (would pinhead to bowling ball as a comparison be overstating the asteroids mass?) what will be the effect on the asteroids orbit of passing so close to an object the mass of earth?
My guess is that an atom to a bowling ball would be a better analogy. The asteroid will indeed be perturbed by the Earth, but not measurably the other way around. Orbital measurements are being taken regualrly and the orbit refined. This process will continue for some time and the results published by the NEO office.
It will be interesting to see what the end result is, a great example of gravity in action. It is probably too much to hope for but it would be nice to see an animation sometime in the future of what the change in the asteroids orbit was.
The last animation of that type that actually sticks in my mind is the one of the voyager paths through the solar system.
"Expect a small asteroid to make big news on February 15, 2013. The gymnasium-sized rock 2012 DA14, 40 or 50 meters (130 to 160 feet) across, will make the closest Earth flyby of a natural object ever predicted well in advance. It will pass within 28,500 km (18,000 miles) of Earth’s surface around 19:25 Universal Time February 15th, reaching 8th magnitude as it whizzes north across the stars at a rate of 0.8° per minute." Feb 16 here. http://www.skyandtelescope.com/obser...189052161.html
Attached is the MSLP map for 5am EDST (18 UT) on Saturday 16 Feb.
Perth will see DA 14 for longer than the other capitals.
Is anyone in Perth planning to image the event?
The asteroid's position varies a lot depending on your location.
The attached file is for Brisbane and Perth.
SOLAR PRESENCE (OBSERVING SITE)
Time tag is followed by a blank, then a solar-presence symbol:
'*' Daylight (refracted solar upper-limb on or above apparent horizon)
'C' Civil twilight/dawn
'N' Nautical twilight/dawn
'A' Astronomical twilight/dawn
' ' Night OR geocentric ephemeris
LUNAR PRESENCE WITH TARGET RISE/TRANSIT/SET MARKER (OBSERVING SITE)
The solar-presence symbol is immediately followed by another marker symbol:
'm' Refracted upper-limb of Moon on or above apparent horizon
' ' Refracted upper-limb of Moon below apparent horizon OR geocentric
'r' Rise (target body on or above cut-off RTS elevation)
't' Transit (target body at or past local maximum RTS elevation)
's' Set (target body on or below cut-off RTS elevation)
So what will this look like through binoculars or a telescope? Will it be visible? What about photographing it? Will it be just like photographing a comet or is it moving a lot faster? (Comparatively)?
So what will this look like through binoculars or a telescope? Will it be visible? What about photographing it? Will it be just like photographing a comet or is it moving a lot faster? (Comparatively)?
Baz.
Its magnitude varies rapidly and it also moves rapidly, much faster than a comet.
You will be able to see it in binoculars for a while. It will be like a faint moving star.
Glen, if it's magnitude is changing so quickly, what do you think the best time to observe it in binoculars would be for Brisbane (I have 10x60's)?
I was looking forward to seeing it come within 3 degrees of Comet Lemon & making a nice triangle with 47Tuc at 1.20am Brisbane time on the 16th. I need to see this!
I came across what looks like to be a gem of a site for tracking this comet (thanks Teale!).
Quote:
There are three catches however. The first is that 2012 DA 14’s close encounter with the Earth is so close that the asteroids encounter with the Earth will shorten its orbital period from 366 to 317 days. This means that charts generated by most commercial astronomy programs won’t show the correct location of 2012 DA because these programs are not written to allow for the Earth’s gravitational effects.
The second catch is parallax. 2012 DA 14 is coming so close to the Earth that observers on different parts of the Earth’s surface will need to look in a slightly different part of the sky to see the asteroid. This means that you need to make sure the chart you are using is made for your location. One made for an observer, say 50 km away will have you looking in a slighly wrong part of the sky.
Finally, 2012 DA14 will be moving fast across the sky. How fast? According to Canberra, Australia based amateur astronomer and astronomy software writer, by 3.45 am AEST on Saturday 16 February, the asteroid will be at mag 7.9 and moving at 2705” per minute or roughly the diameter of the moon in 45 secs!
So what will this look like through binoculars or a telescope? Will it be visible? What about photographing it? Will it be just like photographing a comet or is it moving a lot faster? (Comparatively)?
Baz, it will move from Octans to the northern horizon and then vanish in the dawn over a couple of hours. JPL Horizons, MPC ephemeris service, Heavens-above and probably others will generate an ephemeris customised for your location.
Ephemeris Type : OBSERVER
Target Body : Asteroid (2012 DA14)
Observer Location : user defined ( your location and altitude)
Time Span : Start=2013-02-15 10:00, Stop=2013-02-16 02:00, Step=10 m
Table Settings : defaults
Display/Output : default (formatted HTML)
those all have a "change" link. I added the "skip daylight" and "show constellations" options to Table Settings.
Lots of good advice from many people here.
For what its worth, here is the process I am using to find and track 2012 DA14.
Head over to Google Maps and centre your observing location. Right-click and click on 'Whats Here'. This will give your exact latitude and longitude to a sufficient degree (no pun intended) of accuracy.
Next, head over to http://ssd.jpl.nasa.gov/horizons.cgi?s_loc=1#top and you can enter the lat and long parameters for your site. I had the site give me coordinates for DA14 in 10min intervals and spent about 2hrs last night plotting the path on the Great Atlas of the Sky.
I've also made a record of all mag 7 or brighter stars that it'll pass with a distance of 20' or less and the exact times of passing. I'll skip along to these stars until I have the asteroid in sight.
I will not have the advantage of a dark site but am hoping to find it in both a 5" refractor and a 12" dob from my city site!
Lots of good advice from many people here.
For what its worth, here is the process I am using to find and track 2012 DA14.
Head over to Google Maps and centre your observing location. Right-click and click on 'Whats Here'. This will give your exact latitude and longitude to a sufficient degree (no pun intended) of accuracy.
Next, head over to http://ssd.jpl.nasa.gov/horizons.cgi?s_loc=1#top and you can enter the lat and long parameters for your site. I had the site give me coordinates for DA14 in 10min intervals and spent about 2hrs last night plotting the path on the Great Atlas of the Sky.
I've also made a record of all mag 7 or brighter stars that it'll pass with a distance of 20' or less and the exact times of passing. I'll skip along to these stars until I have the asteroid in sight.
I will not have the advantage of a dark site but am hoping to find it in both a 5" refractor and a 12" dob from my city site!
Good luck everybody.
Hi Dan,
I've been having trouble finding the Body ID for 2012 DA14
I would love for somebody to tell me whether I'm on the right track here?
1. Plugged my location into http://ssd.jpl.nasa.gov/horizons.cgi (Pic 1)
2. From the generated ephemeris, selected the time period of closest approach (Pic 2)
3. Plotted the RA and DEC for times before dawn twilight (Pic 3)
So, on Saturday morning around 4:40am, I should be looking in the right direction?
I would love for somebody to tell me whether I'm on the right track here?
1. Plugged my location into http://ssd.jpl.nasa.gov/horizons.cgi (Pic 1)
2. From the generated ephemeris, selected the time period of closest approach (Pic 2)
3. Plotted the RA and DEC for times before dawn twilight (Pic 3)
So, on Saturday morning around 4:40am, I should be looking in the right direction?
Chris, you don't really need data before about 2012-02-15 10:00 UTC. Up until then just about any planetarium program will get close. It will be in Octans.
I'd suggest you start earlier. If you go much later than 05:00 (18:00 UTC) you'll be competing with morning twilight.
You can set flags in the "Table Settings" to show constellation ids and not display values after sunrise.
Thanks Andrew, that's why I extracted just the relevant data.
If I go much earlier I'm going to be struggling with the lower magnitudes.
My dob is out of action at the moment so I'll be using my C6.
But I take heart from the fact that you didn't say I'd be looking in the wrong direction!
Well, rather incredibly, I've been called by NASA today to confirm arrangements for me to be one of the broadcasters of the fly-by live from my observatory. Looks like I may get a dedicated NASA channel and some airtime on NASA TV if the clouds stay off.
) of accuracy.
