Monday20 September 20041:42pm MDT2004-09-20 UTC 1942 last
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The Asteroid/Comet Connection's
daily news journal about
asteroids, comets, and meteors

Today's issue status: done

IndexyesterdayContentsWednesday

Cover: Two image stacks show P/2004 NL21 (LINEAR) in active comet display, found by Maik Meyer in archives from 8 and 15 September 1996 from a U.S. Air Force telescope (GEODSS) on Haleakala in Hawaii used at that time by JPL's NEAT program. The bottom right image is from September 8th. These are screen shots at 100% size from Astrometrica, with colored circles showing the stars used to calculate position. See below for more about this precovery.

News briefs – panel 1/1 Major News for 20 Sept. 2004 previous
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News briefs

Bits & pieces:  Space.com reports today, “Genesis Reentry Observed By Ground, Airborne Instruments.” It says that “Initial reports from ground teams indicate that the reentry was not seen visually against the bright daytime sky, but was recorded by video cameras.” Also, “A sonic boom was heard at all participating ground stations [and an] infrasound record of the capsule cutting through the atmosphere was acquired.” See also A/CC news links regarding the re-entry (“Bits & pieces”) and crash (“Sample returns”).

There is more about observing from Antartica (see 15 September “Bits & pieces”). An Astronomy.com September 17th article reports that “Construction of a fully robotic, 0.8m infrared telescope has already begun at Dome C. Plans call for the Italian Robotic Antarctic Infrared Telescope (IRAIT) to begin observations in December 2005.” And a September 17th Anglo-Australian Observatory news release is headlined, “Radical Antarctic telescope ‘would outdo Hubble.’”

Noticed at SpaceToday.net is a link to a September 17th ARRL item about NASA online satellite tracking tools.

Comet precovery   by Maik Meyer

The timing was right for Maik Meyer when MPEC 2004-S17 appeared Saturday afternoon with the latest observations and a new orbit calculation for what was now comet P/2004 NL21 (LINEAR).

It came right after my little son went to bed and I was preparing for a comet observing session, so I had time without family duties. I quickly checked for earlier images of this comet and SkyMorph indicated two days in 1996 in NEAT data with an asteroidal brightness of 18 mag. I was not very hopeful but almost fell off my seat when I saw the bright 16-mag. comet with a coma and a tiny tail on my screen.

I quickly measured the two days, composed the message to the MPC, and, when I came back from my comet observing, MPEC 2004-S18 had been issued containing the observations and updated orbits for the 1996 and 2004 apparitions. I still wonder why this one slipped through NEAT's detection, because it is so obvious. Now this comet will become numbered — my second precovery which leads to a permanent numbering after 159P/LONEOS.

Maik Meyer is an amateur comet observer, astronomical archive sleuth, publisher of the Catalogue of Comet Discoveries, and discoverer of the Meyer group of comets observed close to the Sun from SOHO. See news yesterday for more about this and other precoveries.

Risk monitoring - panel 1/1 Major News for 20 Sept. 2004 previous
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Risk monitoring yesterday 20 Sept. Wednesday

A set of positions for 2004 RQ252 from yesterday from Mt. John Observatory in New Zealand were reported in the Monday Daily Orbit Update MPEC, and today NEODyS and JPL removed their last impact solutions for this small object. See yesterday's reporting for 2004 RQ252's short story.

Summary Risk Table - sources checked at 1940 UTC, 20 Sep

Object

Assessment

Years

VI
PS
cum
PS
max
T
S
Arc 
days
 2004 RU109 NEODyS 9/142038-20536-6.72-7.1301.627
JPL 9/142038-20535-6.81-7.2101.627
 2004 RQ252JPL 9/20R E M O V E D
NEODyS 9/20R E M O V E D
VI = count of "virtual impactors" (impact solutions)
See A/CC's Consolidated Risk Tables for more and maybe
  newer details, and check the monitors' links for latest info.
Note that only objects recently in view are shown here.
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