Asteroid YU55 - captured it at last

[lukebl]

Hi all,

Whoopee, I managed to capture close-approach asteroid 2005 YU55 this evening at last, after failing to locate it last night. It's fading rapidly, but still at around 13.5 magnitude.

I should have found it last night but it simply didn't seem to be at the predicted location, then I read Freddy's (Frewi808) report which noted that he thought the asteroid appeared to be 25 minutes ahead of its predicted time. So I had another go this evening, taking a series of 30-second exposures in areas ahead of its predicted route and, bingo, one of the images showed an object which had moved during the exposure. I locked onto it and then took a series of 30 second exposures. It was only about 14 degrees from the full moon, and the frames had a huge gradient with one side completely white due to the massive moon glare. However, a bit of playing in Photoshop got rid of some of the gradients. Despite the horrendous glare from the moon, I managed to capture stars down to around 16th magnitude in these unbinned 30-sec exposures. The asteroid actually appears to be around 90 minutes ahead of the postion predicted on the NASA Horizons ephemeris.

Here's an animation of 21 x 30 second frames (total time 10.5 minutes) from about 20:05 UT 10th November 2011, SXVF-H9 cam, 250mm f/4.7 Newtonian. Sorry, no darks or flats (hence the bad gradients and dust bunnies). The field of view is about 25 arc-minutes across.

And here's a screen grab from Carte du Ciel showing where it actually was at 20:00 tonight, and where NASA Horizons said it should be. It might not look much, but it meant I couldn't find it last night. It seems to be on the predicted trajectory, but ahead of its predicted time.

Bye bye YU55, till next time!

[Moonshane]

that's really top work!

[Nexus 6]

nice Luke

good to see you have captured it especially as it has been such a poor spell recently

[malc-c]

Fan-rudy-tastic !

Well done... and love the animation

[Black Knight]

Good catch, great stuff!

[Nillchill]

superb effort, 10 out of 10 for that work.

[hayju01]

Nice one Luke glad to see you got it after your disappointment last night. Do you have a link to the NASA data on this or am i too late to try this tomorrow night?

[ianaiken]

Great, its nice to see someone else capture this also, I've just got a sky of pea soup still, so it's good to see it on SGL.

[JonH]

Well done Luke, great job!

[lukebl]

Thanks a lot, gents.

Justin, the NASA Horizons website is here. It'll be around mag 14.5 tonight, 15.2 tomorrow, and 15.7 on Sunday, fading to mag 19 by the end of the month. I just realised that you can select the co-ordinates according to 'Astrometric' RA & Dec, or 'Apparent' RA & Dec. I used the former, but YU55 is closer to the latter co-ordinates, although still around 25 minutes ahead of its predicted position as Freddy said. That explains why I couldn't find it the night before. What's the point of the astrometric co-ordinates then, if that doesn't give you its real position? Presumably it's something to do with the fixed epoch of the mapping, taking into account the precession of the equinoxes?

[johnh]

Thats an amazing catch of the fleeting little devil.

John.

[robbie c]

Well done Luke that looks amazing

[MikeD]

Top Job.

Mike.

[barkis]

Nice one Luke. You were determined to get it.

It looks an innocent little speck, but it would have caused unimaginable damage and loss of life had it smacked into Earth. I don't mind seeing them at arms length .

Ron.

[Macavity]

Superb! - Should have been within "Video" range, but I was so far from ready.

Even if the weather had cooperated...

[LukeSkywatcher]

Looks great. Well done. I'm amazed it is so bright against background stars.

[Nova]

Thats great, well done

[r3i]

Great result Luke, congratulations!

[spaceboy]

Great job Luke!!!

[lukebl]

Thanks again, all. Incidentally, the asteroid was around 1.3 million miles away from earth when I took these images. It's moved away rapidly from its close approach of 200,000 miles a couple of days ago.

[AndyH]

Sweet capture !!

Superb, Luke !

[lukebl]

Just to show you what I was up against, here's a single frame unprocessed! Boy, the moon was bright. Must clean the dust off sometime.

[Dave Smith]

Excellent work, well done :icon_salut:

Dave

[Beyond_Vision]

Well done Luke excellent work

Regards

Kevin

[tom714uk]

Thanks a lot, gents.

Justin, the NASA Horizons website is here. It'll be around mag 14.5 tonight, 15.2 tomorrow, and 15.7 on Sunday, fading to mag 19 by the end of the month. I just realised that you can select the co-ordinates according to 'Astrometric' RA & Dec, or 'Apparent' RA & Dec. I used the former, but YU55 is closer to the latter co-ordinates, although still around 25 minutes ahead of its predicted position as Freddy said. That explains why I couldn't find it the night before. What's the point of the astrometric co-ordinates then, if that doesn't give you its real position? Presumably it's something to do with the fixed epoch of the mapping, taking into account the precession of the equinoxes?

Or are Astrometric RA & Dec measured from the centre of the Earth, with Apparent RA & Dec being from a particular point on the Earth's surface? This would be significant with such a close-approach object.

Tom