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Report of the Occultation Section 2005

There are very few amateurs joining the observing sections of ASSA and the occultation section is no exception. We rely on a handful of members who continue to enjoy the pleasures of serious astronomy whilst making a valuable contribution to the science.

Once again we have used the predictions supplied by Eberhard Riedel of IOTA for grazing occultations and Edwin Goffin in Belgium for minor planet occultations. The LOW software supplied by Eric Limburg is used for Lunar occultation predictions.

A number of the regular observers continue to enjoy the challenges of occultation observing and have reported the following.

Lunar occultations
Occultations were observed by Jannie Smit (Pretoria; disappearances 22, reappearances 2), Peter van Blommenstein (Simons Town; disappearances 48) and Cliff Turk (Cape Town; disappearances 31).

Jan Hers was in the Karroo at the time of the May 4th eclipse and observed the occultation of Alpha Librae. This star underwent a grazing occultation at a site near Beaufort West but unfortunately no observers were able to travel to the graze line.

Minor planet observations
In past years we limited our efforts to observing stars brighter than about 10th magnitude. During the year 2004 there were not many convenient minor planet occultations of stars this bright. However a number of possible events were attempted but no hits were recorded.

Tim Cooper observed misses for all these events: 51361 2000 SS124 (May 02), Tatsuo (June 11), Delia (July 17), Aslog (August 23) and Toutatis (September 27). Francois de Jager also observed a miss for the Delia event.

The observers who participated are Magda Streicher (Pietersburg), Jannie Smit (Pretoria), Tim Cooper (Bredell), Brian Fraser (Henley on Klip) and Francois de Jager (Vanderbijlpark).

 

Report of the Occultation Section 2004

This was one of our less active years for a long time. This was due partly to the director not being able to spend as much time as he would have liked on the running of the section due to work and domestic commitments.

However a number of the regular observers continue to enjoy the challenges of occultation observing and have reported as follows.

Lunar occultations were observed by Jannie Smit (Pretoria; 10 disappearances, 3 reappearances), Peter van Blommestein (Simons Town; 48 disappearances) and Cliff Turk (Cape Town; 26 disappearances, 13 reappearances).

In November 2003, there was an occultation of a star by Titan, one of Saturn's moons, and this event caused much interest in Europe. A team of observers from France and Germany travelled to Southern Africa to observe the event and amateurs all over the country were alerted. Unfortunately the eastern and northern portions of the country were clouded out. Good results were obtained in Namibia, Cederberg and Sutherland and by Albert Jansen in Prince Albert.

There were not many minor planet occultations of bright stars and far fewer events were attempted. One success was obtained by Tim Cooper who observed an occultation by the minor planet Zerbinetta on 2003 April 9/10.

Obtaining a good time signal is still one of the major obstacles to getting good observations and this problem needs to be solved if we are to attract new members to this interesting aspect of amateur astronomy.

Brian Fraser (Director)
 

Report of the Occultation Section 2003

[Updated: 2003.11.19 Source: mnassa, 62, 11, 296]

During the year 2002 the number of people doing occultation observations continued to dwindle. There were a number of enquiries from amateurs around the country who had expressed an interest, and predictions were provided to them, however none of these observers has so far reported any observations.

Once again no grazing occultation expeditions were organised. No doubt this is due in no small part to the general security problems in the country.

Reports of lunar occultation observations were received from only two observers: Cliff Turk (26 disappearances, 15 reappearances) and Brian Fraser (3 disappearances).

Minor planet occultations

We are indebted to Edwin Goffin, Belgium, for providing minor planet occultation predictions, and to Jan Manek of Stefanik Observatory in the Czech Republic for sending updates of shadow tracks. These updates have proved to be so useful that we now no longer alert the entire country for an event and only advise those observers who happen to be within the predicted shadow path. This has resulted in far fewer negative results as observers concentrate on the predictions pertaining to their sites.

Two events produced positive observations during the year. One was observed by Magda Streicher in Polokwane (Pietersburg), and the minor planet Croatia was seen to occult a star by Jannie Smit in Pretoria and Bert van Winsen in Midrand. Although there was some difficulty in matching the reported times for this event, it did confirm the path of the shadow track.

It is regretful that we do not have more observers taking part in this activity as single observations, like that obtained by Magda Streicher, do not assist in determining the dimensions of the minor planet. Two observations of a single event are a hundred times more valuable than a single observation.

Other observers in the section, who did not have any positive occultations in the year, but nevertheless have participated are Bert van Winsen, Cliff Turk, Francois de Jager, Hugh Lund, Tim Cooper and Peter van Blommestein.

 

 

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