(10) Hygiea Occults 4UC 574-027283 – August 29, 2014

I know a few others in the RECON community were planning to attempt this event. A major obstacle for many, was the very low elevation of 14 deg. in the east.  The fact that the event occurred at around 3 a.m., probably discouraged a few other potential observers. For me, those challenges, and a few more, were also very real. An interesting aspect of this event as noted on Steve Preston’s info page, was that the target star was one component of a relatively close double star (5 arc seconds separation, 12.6 and 13.8 mag). This factor was really only significant when attempting to analyze the event with LiMovie and subsequently by Occular and/or R-OTE for timing calculations. As you can see from the light curve, the event was indicated by a very low magnitude drop. The predicted mag drop was 0.5, but this was calculated for only the one component of the double system that was occulted. At the focal length used to make the recording the three components (asteroid and two stars that make up the double) cannot be separated in the aperture ring of LiMovie. Because of the additional star the resulting mag drop was somewhat lower than that predicted. A real added treat would have been if the position angle (PA) of the double system would have been such that both stars would have been occulted by Hygiea. In this case though, Hygiea passed just to the celestial north of the doubles second component. The light curve below represents my estimates of the occultation timings and is not the final IOTA official data.


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