My congratulations to Dave Storey on his successful observation of the occultation of the star TYC 0694-01184-1 by asteroid 444 Gyptis. As the satellite image shows, the Isle of Man had the good fortune to have the only window of opportunity in the cloud that covered the rest of the UK.
 UK Satellite Image for 14th October 2007 Image: © Copyright 2007, EUMETSAT/Met Office |
Jon Harper
| ASTEROIDAL OCCULTATION - REPORT FORM - EAON | |
| EUROPEAN ASTEROIDAL OCCULTATION NETWORK | |
| Date: 14th October 2007 | |
| Target Star: TYC 0694-01184-1 | |
| Asteroid: 444 Gyptis | |
| OBSERVER | |
| Name: Dave Storey | |
| OBSERVERING STATION | |
| Nearest City: Foxdale | |
| Long: W 004° 37' 35.3" | |
| Lat: N 54° 10' 39.6" | |
| TIMING | |
| Occultation Recorded? | |
| "S"tart observation"I"nterrupt-"s"tart"D"isappearance "B"link"F"lash"E"nd observation "I"nterrupt-"e"nd"R"eappearance"O"ther (specify) |
|
| -S: 00:48:20 | Voice recording of time signal on MP3 recorder. |
| O: 00:50:34 | Star and asteroid merged into point source. |
| -D: 00:55:11.3 | Combined asteroid/star faded. Star blinked twice, very quickly? |
| O: 00:55:23 | Definitely faded. |
| O: 00:55:43 | Back to normal brightness? |
| O: 00:56:18 | Hard to tell if the star/asteroid back to normal brightness. |
| O: 00:56:33 | Star/asteroid back to normal brightness but did not see step in brightness. |
| O: 00:59:31 | Star and asteroid still merged into point source. |
| O: 01:00:07 | Possible asteroid and star separated. |
| O: 01:00:27 | Star blinked out a second or two? Possible poor seeing effect? |
| O: 01:01:54 | Star and asteroid definitely separated. |
| -E: 01:02:05 | End observation. |
| EQUIPMENT | |
| Type: SCT Meade LX200 GPS | |
| Aperture: 0.4m | |
| Magnification: x250 ( 40mm Plossl + 2.5x Barlow) | |
| Mount: Equatorial | |
| Motor Drive: On | |
| TIMING & RECORDING | |
| Timekeeping: Recorded time signal on MPS player. Stop watch used on replay of MP3 | |
| Mode of recording: Visual observation recorded verbally onto MPS | |
| Device of recording: | |
| OBSERVING CONDITIONS | |
| Atmospheric transparency: Good | |
| Wind: Windy outside of dome, no effect inside observatory | |
| Poor: | |
| Temperature: | |
| Minor planet visible: Visible until merged into star image. | |
| ADDITIONAL COMMENTS | |
The actual occultation was well defined in the drop in magnitude of the combined star/asteroid image. This combined image did blink once or twice at this instant. Seeing effect? Very short duration blinks. I did not see a well defined increase of the star/asteroid image, and would appear to have been a gradual rise. So I could not determine the duration of the occultation. Just after the asteroid was seen separated from the star, I did see the star blink out towards the end of the observation, but not sure if this was caused by poor seeing.
|
|
| David Storey, Isle of Man | |
As can be seen from the diagram, by turning just a few accurate timings of an asteroidal occultation into chords, the shape of the asteroid begins to be revealed. I hope more members will be encouraged to contribute to this fascinating and useful branch of Astronomy. Click anywhere on the image below to see the larger version.
 Profile of the Asteroid 444 Gyptis Image reproduced courtesy of Eric Frappa |
