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Дата изменения: Wed Feb 16 17:10:01 2005
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Поисковые слова: arp 220
Siding Spring Survey Survey/Media
Uppsala Schmidt Telescope and SSS Logo

 

Survey Commences 

After a couple of visits by Steve Larson and Ed Beshore in late 2003 and early March 2004 to deal with various hardware issues and to install the new survey code, regular surveying commenced in mid-March 2004. There will be a period of a few months whilst we become aware of the quirks that the Uppsala presents and to optimise its operation. However, the initial results are most satisfying and new objects have been found from the very first night.

A media release from the ANU and UA about the commencement of the survey and its first discoveries is available at the following links:

 ANU-RSAA News of the Month 

 UA Media Release 

Sky Coverage

At the moment we are surveying around 140 square degrees of sky per night to around mag 20.0R, mostly south of declination -30. Once optimised we expect to cover about double that. It is also possible we will operate in two modes, the other being increased sky coverage with a trade off in depth of search. The nightly sky coverage for the Uppsala can be examined at the MPC's  Sky Coverage Plots . [Click the radio button for 'Include the following observers:' and select 'E12', the MPC code for the Southern Sky Survey.]

Results

On March 16, our very first night of systematic surveying, we detected a mag 19R object in Corvus that didn't quite reach our criterion for reporting as an unusual object. It was reported at the end of the night as part of the routine astrometry. Three days later the discovery by LINEAR was announced ( MPEC: 2004-F40 ) of the large Apollo, 2004 FE3, with our observations predating the LINEAR discovery by one day! This object is around 1-3 km across and is a potential threat to the Earth in the long term.

A better result was achieved earlier on the same night with the recovery of the 'lost' asteroid 1998 SE36 ( MPEC: 2004-F08 ). Not seen since it's discovery, this ~400m Amor asteroid, had a positional uncertainty of around +/-10 deg but was easily swept up by the Uppsala at mag 17.5R some 7 deg west of the nominal prediction. We notified the MPC of the recovery and they then identified observations of this same object taken the previous night by the NEAT survey at Palomar.

Several further nights of surveying produced nothing of interest, until on March 29, Gordon Garradd detected two very fast moving objects, each around mag 18R only 2 degrees apart in Centaurus and both moving at 4 deg/day. Fellow Uppsala observer Rob McNaught was observing NEOs with the 1.0-m at Siding Spring as part of our regular program of follow-up observations. He quickly confirmed both objects and followed them through till dawn. Additional observations the next night by McNaught with the 1.0-m, by Alan Gilmore and Pam Kilmartin at Mt John Observatory in New Zealand and by amateur astronomer James McGaha in Arizona allowed the orbits to be well characterised and published.

The first object, 2004 FH29, was announced on MPEC: 2004-F87 . It is a relatively small object, only 30-100m diameter in an 2.1 year orbit that brings it just inside the Earth's orbit. It's path does not intersect the Earth's so it cannot collide in this current orbit.

Discovery images of 2004 FH29

Discovery images of 2004 FH29 on 2004 Mar 29
0.5-m Uppsala Schmidt
(c) ANU/RSAA 2004

Animated image, please wait
for all frames to load.

The second object, 2004 FJ29, was announced on MPEC: 2004-F88 and is more interesting. A larger object at 100-300m diameter, it takes only 10.5 months to orbit the Sun, meaning most of the orbit lies closer to the Sun than the Earth. Its closest approach to the Sun is inside the orbit of Venus, but as with the previous object, it poses no current threat to the Earth.

Discovery images of 2004 FJ29 on 2004 Mar 29
0.5-m Uppsala Schmidt
(c) ANU/RSAA 2004

Animated image, please wait for all frames to load.

Discovery images of 2004 FJ29

Summary of the Survey so far...

After only two weeks of systematic surveying, we are pleased with these initial results. The combination of two telescopes, the Uppsala for discovery and the 1.0-m for follow-up (for about one week per month) allows the Uppsala more freedom to continue its searches rather than dedicate time to its own follow up. Some additional software improvements have been started by Ed Beshore and Eric Christensen as part of the optimisation process. The Uni. of Arizona team have done a great job in getting the survey fully operational. Things should only improve!

 A listing of the discoveries so far can be found here. 

 Back to Previous News 

 


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