MNASSA : Monthly Notes of the Astronomical Society of South Africa - Volume 72, Issue 5_6, June 2013

Roy Duchesne Fairbridge Smith was born on 26 April 1930 in Kraaipan, Mafikeng where he grew up on a farm. He matriculated from Pretoria Boys High School and started work as a scientific assistant at the CSIR's National Physical Laboratory (NPRL) in 1948. Here he was involved (amongst other things) in the development and maintenance of the National Measuring Standards (NMS) of Mass, Pressure and Length.

The purpose of this investigation is to demonstrate a low-cost method for measuring weak, rapid variable stellar flux with standard amateur class telescopes and CCD cameras. The nature of the flux under discussion is optical, periodic and in the millisecond time frame. Combining measurements spaced over a period of days to improve signal to noise (S/N) ratio is possible, but requires unprecedented timing accuracy, not common to optical astronomy (Eastman, J. et al. 2010). A typical related application is measuring signals from a pulsar in optical wavelengths. A low cost system will be introduced to demonstrate this technology, capable of resolving the light curve of the 16.5 magnitude pulsar in the Crab Nebula, with a 20cm telescope.

For many years amateur astronomers have been using simple radio receivers to monitor the effects that solar flares have on the Earth's ionosphere and the knock-on effect that this has on the propagation characteristics of low frequency radio stations. These systems are variously known as SES recorders (Sudden Enhancement of Signal) or SID recorders (Sudden Ionosphere Disturbance) and operate at frequencies around 20 kHz. Stanford university have developed a system that does not require a radio receiver and utilizes the power of a sound card in a small computer, which they call the Supersid. Software supplied monitors up to ten transmitting stations on a continuous basis. The radio stations that are monitored are used by the military to communicate with submarines out at sea. It is only the carrier wave strength that these receivers are interested in. SID recorders run 24 hours a day, require very little maintenance and work whether it is rainy or clear. All they require is an antenna, a small amplifier circuit and an old computer with a sound card.

This posthumous publication of an article by Jan Hers (see obituary in MNASSA Vol. 69 nos 9 & 10) recounts South Africa's involvement in what can be called the beginning of the Space Age. The launch of Sputnik 1 on 4 October, 1957, during the International Geophysics Year (IGY) caught most of the world by surprise, primarily because the United States was planning to put about six satellites into orbit during IGY. Africa was the first land mass crossed after a rocket was launched from the US and this was the motivation for South Africa's involvement. Jan Hers' detailed memories of these times makes for interesting reading.

Dr William Stephen Finsen was Chief Assistant of the then Union Observatory in Johannesburg. In 1956 he became Union Astronomer and eventually the one and only Republic Astronomer when South Africa became a Republic in 1961. These reminiscences are interesting for the background detail he gives, see article in this issue on "Moonwatch in South Africa". His remark that he "... was not prepared to see the Observatory turned into a satellite station..." came after the International Geophysical Year (IGY) was over. His feelings were almost prescient, echoing those of many of the astronomical community today, who don't see astronomy being a "space science"!

These form an important part of a research facility, often as a sort of prepublication discussion or a discussion of an individual's current research, and as such it is virtually impossible to "publish" this material. However by recording the topics discussed in the form below does indicate to those, who are unable to attend, what current trends are and who has visited to do research: it keeps everyone 'in the loop' so to speak.

In antiquity the Capricornus constellation was seen as a monster with the head and forelegs of a goat and the posterior of a fish. The creature could almost be compared to the so-called Mermaid but could also sometimes, in the case of Capricornus, refer to the Fishman.