2004 BY1
2004 Jan 18 01:34-02:08 UT
Mag +19.3. Stacked for motion of 6.2"/min in p.a. 271°
Each frame 11x20s exposure. Field 10'x10', N up.
0.30m f/6.3 Schmidt-Cassegrain + CCD. P Birtwhistle (J95)

The Asteroid/Comet Connection's
daily news journal about
asteroids, comets, and meteors

Today's issue status: done, updated

• News briefs – new-found NEOs & Hubble news
• Risk monitoring – JPL & NEODyS have posted 2004 BJ11 & NEODyS has also posted 2004 BE11, 2004 BV1 & 2004 BW1

Today's cover is from Great Shefford Observatory's participation in confirming 2004 BY1, which was soon posted with impact solutions. On his Methods page, Peter Birtwhistle explains why and how he stacks multiple short exposures instead of using long single exposures. The three frames here were each assembled from eleven 20-second exposures. The faint fast-moving object (tick mark) is barely discernable, but this was all that was needed to report astrometric data. Background stars appear as streaks or pearl strings.

New-found NEOs:  As A/CC reported, the Minor Planet Center (MPC) announced only ten new objects in the first two weeks of the year, a period that included the full Moon. The pace has picked up, with nine announced today, helping wipe clean what had been a busy NEO Confirmation Page (NEOCP), and eight others were announced in the previous two days.

MPEC 2004-B22 today announces 1999 AJ39, an object posted to the NEOCP this morning by Spacewatch and quickly confirmed by Grasslands Observatory. It has been linked to observations made with the same Spacewatch 0.9m telescope on 15, 16, and 19 January of 1999. At H=22.4, 1999 AJ39 is on the order of 110 meters/yards wide.

Yesterday's MPEC 2004-B12 announced PHO 2003 YM137 by giving "additional observations" from the Spacewatch 0.9m telescope December 21st and from LONEOS January 13th, along with the Spacewatch 0.9m observations from early yesterday that put this object on the NEOCP, after which it was confirmed

by Starkenburg and Gnosca observatories. A check with the Minor Planet Ephemeris Service (MPES) shows that the discovery observations came from LINEAR December 27th, and LONEOS spotted it two days later. 2003 YM137 is estimated from brightness to be about a half-kilometer (one-third mile) wide.

Of these 17 discoveries, only that one goes to LINEAR, and LONEOS has one, while three each go to the Catalina Sky Survey (CSS) and NEAT (two at Mt. Palomar, one at Haleakala). The other nine credits all go to Spacewatch's 0.9m telescope. Three of the 17 are categorized as PHOs, and five are currently listed with impact solutions by JPL and/or NEODyS, including two of seven small objects with absolute magnitudes (H) greater than 22.0.

Hubble:  Sky & Telescope from yesterday has the most optimistic report yet about Friday's announcement (see "NASA funding") that the Hubble Space Telescope will not be getting a repair and upgrade visit from the Space Shuttle.

Risk monitoring 19 Jan.

Today NEODyS posted 2004 BV1 and 2004 BW1, and JPL has posted 2004 BJ11.

2004 BV1 was posted yesterday by JPL, and today's Daily Orbit Update MPEC (DOU) reports observations from this morning from the Spacewatch 0.9m telescope, which discovered it. JPL has now reduced its count of highly preliminary impact solutions and slightly raised the risk assessment for this object, which is roughly estimated at about a third of a kilometer across.

2004 BW1 was announced in MPEC 2004-B09 yesterday, discovered Friday morning with the Spacewatch 0.9m telescope in Arizona, which kept after it Saturday morning and again early Sunday, when Grasslands Observatory in Arizona also confirmed. Today's DOU doesn't carry new observations for this object, which is also roughly estimated be around a third-kilometer wide.

Another Spacewatch 0.9m telescope discovery, 2004 BJ11 was found yesterday morning and

confirmed early today by that telescope along with Powell (Kansas) and Grasslands observatories. It was announced in MPEC 2004-B18 with H=22.1, barely over the line that categorizes it as not "potentially hazardous." JPL has H=22.3 and puts the size at 117 meters, and gives a low risk assessment.

0010 UTC update:  NEODyS is now also listing 2004 BJ11 and has posted 2004 BE11, a Catalina Sky Survey (CSS) discovery yesterday announced today in MPEC 2004-B14. Its width may be under 400 meters.