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HD 209458 (Osiris) -  Magnitude Measurements during Extra-Solar Planet Transit (2005-08-08)

The sole objective of this 4h 20m session was to attempt to record the transit of extra solar planet HD 209458b across its sol HD 209458 (Osiris)

- Initial problems encountered with slight frost in CCD camera (recently regenerated desiccator hadn't had chance to dry out humidity) and software problems associated with auto positioning the telescope onto the precise required position.
- 552 images were recorded over a period of 3h 50m  (15 sec exposures through V filter)
- Inconsistent sky conditions and deteriorating sky conditions with cloud after 01:00 h UT reduced data quality.
- A description of the attempt and results has been compiled. 
- Analysis suggests an overall dimming of ~ 0.01 mag during the time of the transit, but this is unfortunately within the 
uncertainty range of the measurement (typically +/- 0.01 to +/- 0.02 mag). Detection of the dimming event was also compromised by having insufficient data prior to ingress and deteriorating sky conditions around the time of egress. 
- On this occasion I can not claim to have detected the extra solar planet HD 209458b. However I have probably learnt enough and given myself confidence that it would be worthwhile to make a future attempt  (next suitable observing dates are in October 2005).

Graph showing differential magnitudes for HD 209458  (Corrected for B-V colour difference between HD 209458 and Comparison Star)

Graphs shows points representing the average differential magnitude  in each 5 min period. High/Low lines are plotted at +/- 1 S.D.  Data may possibly shows an overall dimming of ~ 0.01 mag during  the time of the transit, but this is unfortunately within the  uncertainty range of the measurement (typically +/- 0.01 to +/- 0.02 mag). Detection of dimming is also compromised by having insufficient data prior to ingress and deteriorating sky conditions with cloud around the time of egress.

Example V Filter image of HD 209458 HD 209458 (V), HD 209346 (C), GSC 1688:1766 (K)

Annotated CCD Image 15 sec exposure (V filter) 2005-08-05  22:30h UT(#91090)

Previous Images : 2002-10-02 /  2004-08-20

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