November ended up providing the most observing time at Great Shefford since Nov 2005, 105 hours over 16 nights.
The NEO highlight of the month was 2006 WV, discovered on Nov 17th with the 0.68-m Schmidt at Catalina. At 20th mag and moving at a moderate 2"/min at discovery it was added to the NEO confirmation page and was searched for on the evening of Nov 18, but not found. Unusually it was outside the uncertainty area predicted by the Minor Planet Center, reason being that it had unusual motion because it was headed almost directly for us and was accelerating rapidly towards a very close encounter at 10am on 21 Nov, within the orbit of the Moon.
LINEAR and the Mt. Lemmon telescope of the Catalina Survey picked it up again less than 24 hours later and it was observed from Great Shefford on Nov 19.0 UT, moving at 6"/min and at mag +19. The next night was cloudy, but by 9pm on 20th Nov it had brightened up to mag +16.5 and was racing along at 150"/min! By this time it was about double the distance of the moon and closing fast. It was followed on and off all night, finally lost to the morning twilight at 6:47am on 21 Nov with the Sun just 7 degrees below the horizon, by which time it was moving at 414"/min (or the apparent diameter of the moon in about 4 minutes), mag +15 and just at the point of crossing inside the moons orbit. Although not reported again, closest approach was 3 hours later at a distance of 349,900 Km (0.91 Lunar distances).
Tuesday, 5 December 2006
Monday, 6 November 2006
2006 October notes: 2006 RZ and 2006 TA8
The month started off with Apollo 2006 RZ (mentioned last month) passing close by the Earth on Oct 6/7. It was tracked on the 6th until about 20:15UT, moving at 86"/min at 15th mag. those positions being the last reported of the object. However, it was picked up again 4.5 hours later, through a gap in the trees, just 10 degrees above the north horizon, moving very obviously between frames. By then it was at the unusually large phase angle of 119 degrees, but unfortunately there were too few comparison stars visible in the images to measure positions.
A number of good nights during October were used to go for some very faint NEOs, an increasing number of which are being put on the NEOCP, mainly by the Catalina and Spacewatch surveys. However, there were also a proportion of bright and often fast moving objects discovered, including 2006 TA8, discovered by LINEAR at high northern declinations on Oct 12 and followed as a 16th mag object on Oct 13, 17 & 22 from Great Shefford, after which it disappeared south in the morning sky.
A number of good nights during October were used to go for some very faint NEOs, an increasing number of which are being put on the NEOCP, mainly by the Catalina and Spacewatch surveys. However, there were also a proportion of bright and often fast moving objects discovered, including 2006 TA8, discovered by LINEAR at high northern declinations on Oct 12 and followed as a 16th mag object on Oct 13, 17 & 22 from Great Shefford, after which it disappeared south in the morning sky.
Thursday, 5 October 2006
2006 September notes: 2006 RZ, 2006 SU49 and 2006 SO198
Generally poor weather continued here during September, still, some work was done on 14 nights, but again few long runs on any particular object could be done.
2006 RZ is a relatively rare amateur NEO discovery, having been picked up at 18th mag by H. Michels from Herrenberg on Sep 4th. It was followed from early September through to the end of the month, passing about 5 lunar distances away in the first week of October having brightened to mag 14.
Some other interesting objects were followed, 2006 SU49 being posted as an impact risk at Torino scale 1 for a number of days before being removed after being found on old NEAT and Sloan archive images going back 5 years.
2006 SO198 was discovered by LONEOS on Sep 29 and was confirmed from Great Shefford while on the NEOCP. It was at the 'fast' end of it's uncertainty area, mag 18 and moving at about 3"/min, about 11' away from the prediction. Less than 4 days later it was to make a pass just outside the orbit of the moon. It was last seen the day before at 16th mag moving at 30"/min, but would have been 14th mag and moving at 800"/min at closest, but it would have been only visible from S. Africa-India and was not reported.
2006 RZ is a relatively rare amateur NEO discovery, having been picked up at 18th mag by H. Michels from Herrenberg on Sep 4th. It was followed from early September through to the end of the month, passing about 5 lunar distances away in the first week of October having brightened to mag 14.
Some other interesting objects were followed, 2006 SU49 being posted as an impact risk at Torino scale 1 for a number of days before being removed after being found on old NEAT and Sloan archive images going back 5 years.
2006 SO198 was discovered by LONEOS on Sep 29 and was confirmed from Great Shefford while on the NEOCP. It was at the 'fast' end of it's uncertainty area, mag 18 and moving at about 3"/min, about 11' away from the prediction. Less than 4 days later it was to make a pass just outside the orbit of the moon. It was last seen the day before at 16th mag moving at 30"/min, but would have been 14th mag and moving at 800"/min at closest, but it would have been only visible from S. Africa-India and was not reported.
Tuesday, 5 September 2006
2006 August notes: 2006 ON1, 2006 QV89, 6Q0B44E
Although some work was done on 16 nights in August, many sessions were interrupted by cloud with just a couple of nights judged as good. Most of the NEOs followed were observed on single nights only, the exception being Apollo 2006 ON1 with three nights.
Apollo 2006 QV89 was observed while it was on the NEOCP and is interesting because its minimum orbital intersection distance with the Earth (MOID) is currently given as 0.00001 AU or about 1,000 miles. At the time of writing (Sep 5th) it is listed with a 1 in ~800 chance of collision with Earth in 2019, so just as well it is only about 30 metres in diameter... Further positions in the coming days are desirable.
On Aug 29th positions for 6Q0B44E were obtained, discovered by the Catalina survey the day before and subsequently found to be in an unstable 80 day orbit around the Earth. It is still unclear whether this is an artificial satellite re-captured by the Earth similar to the Apollo 12 S-IVB third stage J002E3 back in 2003 or whether it is a very small (1-5 metre diameter) NEO temporarily captured by Earth. As noted by Bill Gray, with the current data, it looks as if this object probably entered the Earth/Moon system sometime between about 2000 and 2003, though dates as far back as 1991 are quite possible. Paul Chodas (JPL) comments that it will stay in Earth orbit for at least three more years.
Apollo 2006 QV89 was observed while it was on the NEOCP and is interesting because its minimum orbital intersection distance with the Earth (MOID) is currently given as 0.00001 AU or about 1,000 miles. At the time of writing (Sep 5th) it is listed with a 1 in ~800 chance of collision with Earth in 2019, so just as well it is only about 30 metres in diameter... Further positions in the coming days are desirable.
On Aug 29th positions for 6Q0B44E were obtained, discovered by the Catalina survey the day before and subsequently found to be in an unstable 80 day orbit around the Earth. It is still unclear whether this is an artificial satellite re-captured by the Earth similar to the Apollo 12 S-IVB third stage J002E3 back in 2003 or whether it is a very small (1-5 metre diameter) NEO temporarily captured by Earth. As noted by Bill Gray, with the current data, it looks as if this object probably entered the Earth/Moon system sometime between about 2000 and 2003, though dates as far back as 1991 are quite possible. Paul Chodas (JPL) comments that it will stay in Earth orbit for at least three more years.
Tuesday, 1 August 2006
2006 July notes
With the summer monsoon having taken hold in the southern USA, stopping the big surveys from operating for most of the month, time was spent catching some NEOs at their second and subsequent oppositions.
Working with Roger Dymock we also went after some more normal main belt minor planets on the FUAP (Follow Up Astrometric Program) target list at http://asteroidi.uai.it/ which is maintained by Sergio Foglia on behalf of the UAI Minor Planets Section. This site lists minor planets of mag +18.5 or brighter that are in need of observation, whether newly discovered and under-observed, or awaiting recovery at their second or subsequent oppositions.
The last week of the month saw a flurry of NEO discoveries from the surveys in a brief respite from their bad weather, with several objects at mag 16-17.
Working with Roger Dymock we also went after some more normal main belt minor planets on the FUAP (Follow Up Astrometric Program) target list at http://asteroidi.uai.it/ which is maintained by Sergio Foglia on behalf of the UAI Minor Planets Section. This site lists minor planets of mag +18.5 or brighter that are in need of observation, whether newly discovered and under-observed, or awaiting recovery at their second or subsequent oppositions.
The last week of the month saw a flurry of NEO discoveries from the surveys in a brief respite from their bad weather, with several objects at mag 16-17.
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