The 76 km diameter asteroid (325) Heidelberga, mag 12.9, occulted a mag 13.9 star in Cancer for 1.7 s. Their combined merged magnitude was 12.6, so the mag drop during occultation would only be 0.3. (Maximum predicted duration was 6.0 s for an observer on the centre line).

AOTA analysis gives the following:

    D  - 00 14 01.33 ± 0.15

    R  - 00 14 03.03 ± 0.15  

                          Duration : 1.70 s

                         Mid-event : 00 14 02.18 UT

The Tangra light curve shows a dip of 1 or 2 data points at 00:14:00 UT

D - 0 13 59.98 ± 0.10

R - 0 14 00.18 ± 0.10

Depending on processing options, I thought this dip could have been an effect of the noisy signal. Dave Herald (worldwide occultations coordinator) has assessed it has a genuine event, meaning that I recorded a grazing asteroidal occultation.

The event was also recorded by Konrad Guhl (Germany) and Kevin Green (USA). Dave fitted an ellipse to our chords, giving the estimated dimensions of Heidelberga to be 84 km x 70 km.

My first successful asteroidal occultation observation since last July - no thanks to so many events being masked by a neighbour's tree, clouded out or a miss from my location.