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I missed a really fast one - 2021 TX that hit 61"/sec motion ~midnight on Oct 2 in Spain!! Minimum Re was 57.96k km. It reached 15.9 mag, too. I've never found one moving this fast. I only noticed it because I misread 2021 TK as 2021 TX in the results of today's MP DBPS. It passed so fast that the searches for Sep 29, & Oct 1&3 didn't find it. It may have been discovered after close approach. According to the entry in the JPL Small Body Database, the first data used was from Oct 2 so it had already passed us.
Win some, lose some.
Phil S.
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Close for sure, almost to the geosynchronous satellites. That Martian tech is good stuff.
Phil S.
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I subscribed to ESA's NEO Coordination Centre | Planetary Defence Office (this must be the coolest employer name to put on LinkedIn for those people) and there is an interesting note in their October issue: "of the almost 27 000 discovered NEOs, about 25% have an observed arc of less than a week, and 50% have been seen for less than a month. Many of these objects will likely be already unrecoverable at their next favourable apparition, and will have to be rediscovered in the future."
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Talk about assured employment! Even when they find 'em they lose 'em again. These little motes become so faint after close approach I suppose they're impossible to track even with professional equipment. According to Shefer's paper his method provided ~3x better accuracy than the older methods even for short arcs. I guess many of the subsequent passes aren't as favorable as the ones when they get discovered. 2010 CA261 seems to be an excellent example of a 'lost' object.
I wonder what kind of orbit accuracy the MPC gets with a week or a month of observations. Current techniques yield much better accuracy than the photographic methods used in the past. Shefer stated that photographic methods had accuracies of ~1.6 arcsec, while CCD imagers are 10 or more times better.
If you've run any of the ephemerides for these things, it's amazing how fast they brighten & fade in a week or two.
Phil S.