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Tuesday, January 27, 2015


Success! 2004 BL86's flyby seen (26 January 2015)

My sketch of the flyby of Near Earth Asteroid 2004 from 11:40 ACDST to 11:58 ACDST. 114mm Newtonian with 25 mm Plossel eyepiecePredicted chart of the flyby in SkyMap

After a busy Australia day of waking up late, walking down the beach to the Australia Day concert to buy ice- creams, a Barbie with friends and watching the fireworks, I set up the telescope to camp out on 11 Puppis to watch the flyby of Near Earth Asteroid 2004 BL86.

And failed utterly. I had misunderstood the orientation of the images in to scope, and by the time I had confirmed which part of the image was north, the asteroid was long gone.

Once I has sorted my orientation out (with much hopping back and forth to the computer screen inside) I chose the undistinguished star HIP 39095 as my target, as the asteroid passed close to it. I star hopped down, set up about 10  minutes beforehand, sketched the field (and confirmed that I did have the RIGHT field and which way the asteroid would be going as seen though the scope), then waited.

I did a bit of back and forthing to get the areas I wanted directly in the field, with particular stars picked out as the asteroid passed close to them.

And then I saw it. Drifting slowly into the field. I really needed averted vision to see it properly, on the basis of the other stars in the field I would put it at around magnitude 10.4, rather than the predicted 10.1 (I could see mag 10.2 stars okay). It was also running about 5 minutes ahead of schedule, but it's track was pretty close to predicted.

I watched it drift close to, then past, several dim stars in the field, and then out of the field in around 15 minutes. My sketching is pretty rubbish, but is surprisingly close to the actual chart. The spacing of the asteroid positions are not fantastically accurate, but the timed locations next to actual stars is.

I hope I can get up at 4:00 am to see the close pass to M48 Tuesday morning, also hoping the Mayhill iTelescopes aren't clouded out. The SSO ones are, so unless the skies clear soon I don't think I will get any close approach images form SSO.

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