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(meteorobs) OFF-TOPIC: NEO discovery rates?


Saw this on the AAVSO list, and thought it (somewhat) more appropriate here.

Later, y'all,
Lew

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To: "AAVSO-DISCUSSION" <aavso-discussion@physics.mcmasterdot ca>
From: "Marvin Baldwin" <mbald00@hsonlinedot net>
Subject: Re: June observing
Date: Sun, 05 Jul 98 00:24:14 PDT

    Brian Skiff just laid out some amazing statistics about asteroid
discoveries and I've gotta see if I'm understanding this correctly.  The
asteroid survey telescope, the LONEOS Schmidt, just in the month of May
alone, took data resulting in 8000 asteroid position measurements and the
discovery of 145 previously unknown asteroids??
     At the same time, month of May alone, the military project, LINEAR,
took data resulting in 80,000 asteroid position measurements and discovered
3600 previously unknown asteroids about 1% of which were determined to be
near-Earth objects??
     Are these 3600+ newly found asteroids tracked sufficiently to fix
their orbits or are most of them simply lost until they are picked up again
in the future in a similar manner with the possibility of matching them up
with the old data and fixing their orbits at that time?
    Are most of these new asteroids being found when they are nearby or are
they being spotted half way across the solar system?
    Then there is the question concerning the size of the near-Earth
objects (statistically speaking) and the additional question, concerning
the discovery rate, as to how many are expected to be found eventually.

Marv Baldwin
Butlerville, Indiana, USA
- ----------
> 
>  Arne asked some possibly rhetorical questions about our June observing,
>and we've chatted since then, but I'll fill in folks here in case there's
>some interest.
>  We try to run the LONEOS Schmidt, which is an asteroid survey telescope,
>whenever the Moon is less than 80-percent illuminated. After the June Full
>Moon, my colleague Bruce Koehn observed for a few nights with our summer
>student Chris Onken (from Univ of Minnesota), then I took over for a couple
>of nights.  Actually, these were formal training nights for Chris, and I
>didn't do much besides watch.  On the first of these nights Chris chose some
>fields that included our first near-Earth asteroid discovery, 98MQ, so things
>started well. Chris worked alone at LONEOS for three more nights while I did
>follow-up astrometry of asteroids at our 1.1-m telescope; on the last of these
>nights I got a preliminary lightcurve for 98MQ (period of 6-7 hours, but an
>amplitude of only ~0.06 mag.---tough to do accurately at mag. 17.5 with the
>1.1-m telescope).  Then I was back at LONEOS for the succeeding nine nights,
>violating all kinds of Arizona labor laws in the process.  Just about gave it
>all away mentally/physically, too.  Should have gone directly back to Sun-like
>stars photometry at the venerable 21-inch on Mars Hill, but took two days off
>to recoup.  (If I sounded completely incoherent on the NPR interview that
>ran last Monday, it was because I'd just gotten out of bed after the 
>thirteenth of the fourteen nights when they called.)
>  We're taking about 200 data frames of 17.4Mb each on these short summer
>nights; call it 3.5Gb (8Mb per minute!).  The reduction software, which Bruce
>and Chris are working on, is primitive enough that we barely get a handle on
>the moving objects, and certainly nothing's been done to pick up the variables
>and supernovae that doubtless show up on these frames.  We're covering about
>600 square degrees three times each night to R mag. 18, so there's a lot of
>real estate involved.  The reductions, which are done on the fly by four high-
>end Pentium II towers (no keyboard or monitor), are basically complete for the
>moving objects only a few minutes after the final frame is taken. In May, a
>much cloudier and problem-plagued run, we reported about 8000 asteroid
>positions to the Minor Planet Center, among which were 145 discoveries. To
>put this in perspective, during the same period LINEAR (a military project)
>produced _80,000_ positions and was credited with over 3600 asteroid
>discoveries, including half a dozen comets and basically all the near-Earth
>objects found in the interval (some three dozen). (Your military tax dollars
>at work!)
>  I found the June dark run very satisfying aesthetically. Thanks to the
>low winter-like extinction values, which Arne reported on (around 0.12-0.14
>in V), the nights were absolutely gorgeous. The evening & morning twilights
>were likewise wonderfully saturated in color.  I found the zodiacal light
>was readily visible both morning & evening; I got to see a fairly old and a
>quite young Moon; saw the Pleiades go from being difficult in bright twilight
>to being well up in full darkness as Venus slipped past it; saw Aldebaran
>within a day or two of heliacal rising; saw the activity associated with the
>unexpected Pons-Winnecke meteor shower; spent parts of several nights doing
>visual deep-sky observing in the Milky Way and eastwards with my Pronto
>telescope, which showed stars to V mag. 14 on these glorious nights.
>  The most amazing thing of all, of course, was that I got _paid_ to do 
>this!  (Your NASA tax dollars at work!)
>  It appears to be clearing up again tonight, so I'm off to spend some NSF
>tax dollars doing photometry on stars....
> 
>All for now.
> 
> \Brian

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