Simultaneous observations of asteroid occultation last night

I had a successful observation of an occultation event last night March 20 at 23h 41m of star 2UCAC 36297026 by Centaur asteroid (42355) 2002 CR46. The asteroid is about 160km in diameter. There is only a some tentative data regarding this asteroid.

The star was 14.2mag and the asteroid was 19.8 mag.

I took 76 images at 3 second exposures using an Apogee AP8 camera with a 0.9m telescope from Kingsland Observatory, Boyle, Co. Roscommon. I reached 18 mag that would be sufficient to record a possible occultation. In addition Apostolos Christou at Armagh Observatory recorded 90 images at 3 second exposures using a 250mm telescope with SBIG CCD camera.

Two reference stars of similar mag were recorded and photometric profiles of the three stars were graphed. The two reference stars were stable but the event star showed slight magnitude dimming with oscillatory features.

No analysis has been done as to correlation of magnitude to timing.

The photometric profile may indicate that the asteroid was showing features indicative of an accompanying satellite. Its also possible that the dimming with oscillating features, may have also shown that the asteroid was tumbling. However, this is only tentative observations at this stage, there is more data to research on this event.

Apostolis Christou observations also show similar features. We await further analysis from both observatories.

Eamonn A

Eamonn - that's a real feat! Well done.

Are you collaborating on the project with Armagh? When do you expect to complete the analysis? And I'm sure you posted it before ( :oops: ) but do you have the site indicatiing upcoming occultations?

J65 was clouded out on the 20th

Cheers

Dave

The photometric profile may indicate that the asteroid was showing features indicative of an accompanying satellite. Its also possible that the dimming with oscillating features, may have also shown that the asteroid was tumbling.

Or, it could have just been the light from the star peeking out from the valleys between the peaks as it passed by!

Nice work Eamonn. Glad it 'worked out' for you - keep us posted with the results if and when they come.

Seanie.

Dave,

Apostolos Christou alerting me to this event 24 hours ago.

The site for future occultation events is 'PLANOCCULT'.

I have to process more plots with different stars. The original plots early this a.m. appeared to indicate the tentative results as outlined in the previous posting. However, I need to select stars nearby with similar magnitudes and at least be above and below the event star where the occultation took place to give it some consistency.

I can't be precise as to final analysis. Some of this material has already gone to Armagh Observatory this a. m.. There are further quality plots needed which I hope to have complete today. This also will be sent to Armagh this evening. I hope we will know the outcome this week.

BTW, I was up to 5.00 am carrying out long exposure imaging since 8.00 pm last night. The early part of the night the seeing was below average. However, from about 2.00 a.m. it got really good so I could push the telescope to fainter magnitudes of around 21.

Eamonn A

snip - extreme apologies

That is excellent work Eamonn!!