Amateur optical tracking in South Africa during 1957-2014. Part 3.
Initially four Moonwatch stations were set up in South Africa and were all that was required in SA. It should be no surprise that the stations were setup at four professional observatories since the technical and astronomical expertise was available from astronomers. In addition the observatories possessed the necessary infra-structure such as time signals and communications. Each station was given a site number, starting at 0401 and increasing incrementally. (The series starting 0400 was reserved for Africa). These numbers were used to identify a particular station as the geographical co-ordinates were registered in a central database so it was a unique identification. No two sites could have the same number and for an observation to be processed by the various processing centres the observation had to have been made at one of these numbers.
The SA stations were not arranged in a network, but their considerable north-south separation provided a wide observation fan for coverage of all predicted satellite orbits. These stations were so located that for four months of the South African summer satellites were sunlit all night over some parts of the fan.
The station numbers were allocated alphabetically as follows:
0401 Bloemfontein--Team Leader G N Walker, Longitude 26d 13m 35.50s E, Latitude 29d 06m 19.56s S, altitude 1494 metres.
0402 Cape Town 120 Woodgate Road--Team Leader W P Hirst, Longitude 18[degrees] 28' 37.984" E, Latitude 33[degrees] 56' 00.440" S, altitude 7 metres.
0403 Johannesburg--Team Leader Dr C N Williams, Longitude 28[degrees] 04' 30" E, Latitude 26[degrees] 10' 55.3" S, altitude 1806 metres
0404 Radcliffe Observatory ,Pretoria--Team Leader R F Smith Longitude 28[degrees] 13' 43.5" E, Latitude 25[degrees] 47' 18" S, altitude 1542 metres.
Station 0401 Bloemfontein
Bloemfontein in the 1950-1960's could have been regarded as the astronomical centre of South Africa. It was home to two professional observatories--the University of Michigan's Lamont-Hussey Observatory on top of Naval Hill in central Bloemfontein and used for double star observations, and the multi-ational Boyden Observatory situated some 24 km outside of Bloemfontein at Mazelspoort. In addition Bloemfontein enjoyed the best all year round observing conditions.
Initially plans were to set up a MINITRACK MARK 1 radio tracking station south of Bloemfontein with Dr FJ Hewitt, Director of the National Telecommunications Research Laboratory in charge of the project. It was further proposed to set up at the MINITRACK site a teleprinter that would be linked to the Moonwatch teams, the Precision optical-tracking station at Olifantsfontein (also known as the Baker-Nunn station or SC2) and the Marconi Cable and Wireless Station in Cape Town.
Unfortunately for Bloemfontein the MINITRACK station was eventually sited at Harteebeesthoek, near Krugersdorp.
Dr Jurgen Stock was sent to Boyden in Dec 1956 as caretaker/director. He first set in motion the possibility of a Moonwatch station at Boyden when the first recruitment of people for Moonwatch was launched, using articles in two local newspapers--Die Volksblad and The Friend.
According to a detailed reported to Moonwatch headquarters in the United States, the Bloemfontein Moonwatch Group was officially formed on the 12 July 1957 at a meeting held at Boyden Observatory.
Stock left soon after the first meeting and returned to Hamburg at the end of July 1957. He was replaced by Professor H. Haffner (from Hamburg, Germany) who took over as Boyden's Director, giving his full support and enthusiasm to the venture to ensure its success.
It was initially planned to host the Moonwatch site at Boyden and practice sessions were held in the Boyden Library. One of the Moonwatchers--Eric Burton--son of Ernest Burton who was the resident engineer at Boyden--provided his 35 mm slide projector. They put in a slide with a totally black piece of film, which had a pin hole in it so that a ray of light could be projected. By moving the slide across the projection slot, they could simulate a satellite passing across the projection screen. Eric was an amateur enthusiast, whose full-time job was with The Friend newspaper in Bloemfontein, now no more.
Under the guise of the International Geophysical year programme and financed by a grant in aid from the South African Council for Scientific and Industrial Research (CSIR), Boyden received a case of optical lenses from the United States with instructions on how to make simple telescopes which could be used to accurately observe satellites passing overhead. A simple drawing of how to make the telescope (fixed focus) was enclosed in the package. The tube housing the optics was two inch (50mm) galvanised piping with brass turned lens holders. These were machined by Ernest Burton in the Boyden workshop with the help of some volunteers who worked in the Railway workshops in Bloemfontein. The cross-wires in the telescope was a piece of Free State spiders web! Ernest also constructed the mountings which used to support the telescopes. These 50mm aperture scopes were popularly known as Elbow Telescopes.
While the telescopes were being made, Dr Haffner enlisted a team of people to be a Satellite Watch Team using these telescopes. Ernest was one of the team. Observations through the telescopes had to be conducted within two hours after sunset, or within two hours before sunrise, as that was the only time the satellites were generally observable. At other times, during the rest of the night, they passed through the earth's shadow and gave off no reflected sunlight, so were not observable. The programme thus called for several very early morning wake-up calls (3 am).
It appears that originally the Moonwatch station was to be set up at Boyden but this did not last long. However some early observations were made of Sputnik 1--for example an observation made on 31 October 1957 of Satellite 1957 Alpha 1 (Sputnik 1) with station identification "Boyden Observatory Station number 2400", observation no 00614 made at 01h54m42s UT. Station 2400 had geographical co-ordinates 26[degrees] 24' 21" east longitude, 29[degrees] 02' 18" south latitude and height 1387 metres.
On the 29 November 1957 the site, situated in the game reserve on top of Naval Hill, near the centre of Bloemfontein, was used for the first time. Due to the requirement for observers to be present shortly after sunset, or before dawn, this had imposed quite a burden on most of the volunteer observers who were resident in Bloemfontein. This meant that the Boyden folk now had to travel 24 km to reach the new site.
The observation site on Naval Hill was in the old SA Broadcasting Reserve where two buildings were available for use. The one nearest the actual observing site was used to house equipment and materials whilst the further one was used for meetings and the dispensing of refreshments--an essential item in the cold morning hours!
The whole arrangement was very satisfactory, and since the move to the site had taken place there was a distinct increase in enthusiasm as its close proximity to all parts of town made it easily accessible at all times. The team leader was Graham Walker, a civil engineer who worked with Shand's construction company designing and overseeing the construction of dams (among other projects). Prior to that time, the company's engineers had modelled what was believed to be a then-unique hydrodynamic design for passing silt downstream and oversaw the construction of Mockes dam upriver from Mazelspoort.
The meridian pole stood in front of the "operations building", with the line of telescope pedestals running north and south diagonally to the front face of the building with the ground falling from south to north, the pedestals being set at a slope of 1 in 20 to follow very closely the fall of the land and the site was surveyed by Walker to determine the meridional line and the latitude and longitude of the meridian pole was determined as:
Latitude 29[degrees] 06' 19.56" South Longitude 26[degrees] 13' 35.50" East
whilst the height of the ground level above sea level was 4901 feet or 1633.7 metres.
Walker recruited and organized the team and leaders were appointed, and taught to coordinate the setting up of the small telescopes on a preset north/south plain, so that each telescope looked at a different part of the sky with overlapping views. This had to be done at least 30 minutes before the scheduled crossing of the satellite. The telescopes were set up, each on a separate pedestal, fanned out facing skyward--like an open hand of fingers facing upwards. This resulted in only two or three out of a six-person team being lucky enough to see the passing satellite each time, as its precise path was not known. In the very early stages, satellite ephemerides did not exist, so a lot of time was spent/wasted hoping for a sighting. Only later when orbits were better known was it possible to expect a sighting and the observational data was then used to improve the satellite orbit.
When the satellite passed over and one of the observers spotted it passing through the telescope image, he would shout "Satellite!" As the moving image passed through the view and crossed the crosshair wire, he would shout "STOP". One of the team members had a stopwatch and started the watch at the exact moment of the "STOP" command. The stopwatch time was then used to accurately determine the exact time of the crossing when measured against the standard 24-hour chronometer clock, and recorded. The telescope that had viewed the occurrence was then accurately measured for its declination and the resulting information was telexed back to America.
A detailed report made by the Bloemfontein Moonwatch Group to Moonwatch Headquarters at its founding, makes interesting reading. It is referred to in some detail The Bloemfontein Moonwatch Group was officially formed on the 12 July, 1957 at a meeting held at Boyden Observatory. The group was organised on lines which made it possible to decentralise the control and execution of the multitudinous duties involved.
Control was vested in a Central Committee whose membership of the Group at the time of formation was forty, with office bearers as follows:
Director of Boyden Observatory Dr W Haffner Leader of Group G N Walker Deputy Leader of group (photocopy not readable) Secretary Miss J.Stark Treasurer G P N Coetsee Timing Committee-Convenor R van Allemen Star Charts--Convenor R Reynolds Radio and Communications--Convenor H W Clarkson Traffic and Police--Convenor W Watson Transport--Convenor C A E Swanepoel Telescopes--Convenor G E Burton Entertainment--Convenor T R Cooper
A Construction Committee was appointed and was responsible for the preparation of the site for use, and was able to have most of the materials supplied free of charge by local firms.
The pedestals consisted of 6-inch Everite pipes, concreted into the ground to a suitable height. These were then partially filled with soil and the upper 12 inches (30 cm) filled with concrete. A plate with three anchor bolts was then set into the top of each pedestal to correct level, line and distance.
The meridian pole, 41 ft. (12.5 m) in height, had a cross member at the top, extending 11 ft. (3.4 m) on each side and was supported by steel wires.
Fifteen telescopes were constructed by the Telescope Committee and stated to be an "excellent job". These were set up using the meridian mast and provided a meridian arc of 115[degrees] with a 1.5[degrees] overlap with their 12[degrees] field of view. The telescopes thus covered from a zenith distance of 61o south (declination 90[degrees] south) to a zenith distance of 54[degrees] north (declination +25[degrees]).
Star charts were used to locate the satellite in its path across the field of view and were provided by the Boyden Observatory as photographic reproductions of the Skalnate Charts, with white stars and a black background.
Finance of course was always important. The Boyden Council made a donation of 30 pounds and the firm G A Fichardt Ltd made one of 5 pounds 5 shillings. An offer of 15 pounds by Dr Evans from the Cape Team funds was not taken up as it was felt that the Bloemfontein group see to its own finances and not look to other groups--however the gesture was appreciated. A grant of 50 pounds had been approved by the City Council of Bloemfontein and apparently paid to the team. It was subsequently turned down by the Administrator as not being within the authority of the Council.
(The report contained a full list of all members of the team for those interested.)
It soon became obvious that the original 50mm aperture telescopes supplied were completely inadequate for the task of observing the US Vanguard and Explorer satellites so larger aperture telescopes were soon supplied to teams.
Towards the end of 1957 Dr Evans (who was the Moonwatch visual coordinator for South Africa) was approached by Moonwatch HQ and asked whether he could use 20 so called "APOGEE telescopes" at each of the four South African stations. This was subsequently changed by the US Naval Research Labs (who constructed the telescopes) to 50 each for Cape Town and Bloemfontein with none being supplied to Johannesburg and Pretoria with the explanation that they were "too far north to observe the Vanguard satellite"--rather a remarkably incorrect statement! (source Jan Hers Moonwatch in South Africa 1958-1959). Roy Smith of the Pretoria group thought it more likely that Cape Town and Bloemfontein were considered the safest addresses.
50 APOGEE telescopes were installed at Cape Town in Jan 1958. However, at Bloemfontein there was some difficulty as they were unable to field enough observers (it would appear that most of their original 75 observers had rapidly lost interest with the strenuous observing times!).
There is some uncertainty about the exact number of APOGEE telescopes supplied. In MNASSA 1958 Vol 17 Page 4 where David S Evans wrote "Two consignments of additional instruments were delivered to teams at Cape Town and Bloemfontein. Each consisted of 49 5-inch APOGEE telescopes and 18 2-inch telescopes ... etc ..."
The decision to only supply to Cape Town and Bloemfontein naturally dismayed the Johannesburg and Pretoria teams and there was a vigorous protest. Around middle Feb 1958 approval was given for some of the APOGEE scopes at Bloemfontein, but not yet installed, to be transferred to Johannesburg and Pretoria Moonwatch. Five APOGEE telescopes were sent to each location with the five Pretoria Apogee telescopes being installed at the CSIR Site.
Following the first United States satellite launch (EXPLORER 1 launched on 31 January 1958) Bloemfontein obtained its first observations of it on 21 February, made by P J Visagie of First Avenue and Eric Burton. Further observations were made on 23 and 25 February and on 23 February at an almost incredibly low altitude of 17.9 o to the north.
During the period 1957-1958 Bloemfontein reported a total of 52 observations of various satellites to the Moonwatch program. In addition Dr Haffner often used to send messages to Russia with observations of Soviet satellites made by the team.
Peter Usher was one of the Moonwatch team while in his final study years at the University of the Free State. This was before he went and completed his astronomical studies in the USA, where he now lives. Peter used to help with exacting measurements and the transmitting (by Telex) of the information the Moonwatchers got.
Peter recounts an amusing story how, late one evening, he decided to walk up to the telex building from Union Avenue to see if there were any new predictions etc. It was pitch black and he could barely make out the macadamized (tarred, paved) road by the light of the stars. All of a sudden all hell broke out around him with bodies flying through the air. He had walked into the middle of a herd of impala!
At the end of the IGY (International Geophysical Year) program, the team members were each awarded with a lapel pin badge with the IGY insignia on it.
The end of Bloemfontein Moonwatch
It would appear that the Moonwatch team in Bloemfontein was only originally set up for the duration of the International Geophysical Year--about one year. By the end of 1958 it had virtually ceased to operate. The last observation appears to have been made on 19 December 1958. It was of the large PROJECT SCORE (1958 Zeta) satellite which was an Atlas rocket some 80 feet (24 m) long and diameter 9 foot (2.7 m). It was launched on 18 December 1958 into an orbit inclined at 32.4[degrees] to the equator and with an orbital period of 101.5 minutes. The orbit ranged from 118 to 911 miles (190 to 1 460 km) above the earth.
According to a Sky and Telescope magazine article, visual observations of the tumbling of the Atlas satellite were made by G N Walker and his associates. On 21 December they observed a recurring brightness cycle of 63 seconds, each maximum of light intensity being double, with peaks about five seconds apart.
However, the flashing behaviour was quite different on 3 January when the Atlas was seen from Cambridge, Massachusetts, by Moonwatch observers. Although the rocket was some 2 000 km away, it periodically attained an apparent magnitude of +1 during its short life-time.
On 28 December 1961 Moonwatch headquarters wrote to a Mr P J Kruger of the University of the Free State with the comment: "Our records show that the last observations received from Bloemfontein were in December 1958. We cannot but feel that interest is low and unless there is a possibility that observations will again be made on a regular basis, we must give consideration to withdrawing the team from the program."
On 30 March 1962, Moonwatch HQ again wrote and requested that the equipment be sent to the Baker-Nunn Smithsonian Satellite Tracking Station. It detailed 10 APOGEE telescopes, 3 stopwatches, a pair of binoculars and three tape recorders. On 6 April 1962, Bloemfontein Moonwatch was given formal notice by Moonwatch HQ of the withdrawal of the Bloemfontein Team from SAO's Moonwatch network.
However it would appear that the correspondence did not reach P J Kruger (it's not clear what his actual role was with Bloemfontein Moonwatch) as he was no longer at the University of the Free State. On the 3 April 1963 he replied from the South African Wool Textile Research Institute in Grahamstown to the Moonwatch correspondence as follows:
"In 1959 we re-organised the Moonwatch team in Bloemfontein. In 1960 we had it in operation but during that time I left Bloemfontein for Europe and informed your office accordingly. A new team leader was appointed in the person of Mr J Booeyens and his name and address was also forwarded. Unfortunately he left a few months later. In the meantime correspondence did not reach him but was still sent to my old address. Some of these letters came to my attention recently after my return to this country. I refer to your letters of 16 January 1962; 5 March 1962, 6 April 1962 and that of 30 March 1962. The equipment was called back by you but the correspondence did not reach the people concerned. I hope to get in contact with the people in Bloemfontein and trust that you succeeded eventually in getting the equipment. However the equipment as listed is not correct. We had only one tape recorder and not 3 as mentioned"
And so Bloemfontein Moonwatch ceased to exist.
However Bloemfontein was not keen to disappear from the tracking scene just yet!
In 1962 a team was sent out from the USA to Bloemfontein to try and observe the geodetic research satellite ANNA 1B which had a flashing light source on it that was operated under command. The writer recalls reading a short article in a local newspaper at the time but that is about the sum total of the info available on Bloemfontein's involvement.
On 13 February 1963, SYNCOM 1, a small hatbox sized satellite (71 cm diameter and 38 cm high, weighing 35 kg) was launched into a 32[degrees] inclination high altitude orbit by a Thor-Delta booster to mark the beginning of the synchronous communications satellite era.
Initial communications tests conducted from the USNS Kingsport, a tracking ship located off the African coast near Nigeria, were successful but 20 seconds after a ground command was given to fire the spacecraft's apogee motor, all communication with the spacecraft was lost. The cause of the failure was eventually determined to be the rupturing of a tank of nitrogen that was part of the on-orbit control system.
Using search data based on data obtained from the Kingsport, the Boyden Observatory photographed Syncom 1 as a 17th magnitude object some two weeks later. However all attempts to re-establish communication contact with the spacecraft failed.
A special thanks to Dawid van Jaarsvelt (UFS) who spend many hours going through old newspapers in the State Archives and scanning any satellite related articles and pictures--some of which are included in this article.
In compiling this report I would also like to sincerely thank the following people for their input and support: Ellen Alers-reference archivist at the Smithsonian Institute, Washington, USA Eric Burton (New Zealand) Willie Koorts (SAAO), Keith Snedegar (USA), Peter Usher (USA) and the late Roy Smith (Pretoria).
Note. The poor quality of some of the images is due to the fact that the originals could not be located and as a result images were scanned from Newspaper archives.
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|Publication:||Monthly Notes of the Astronomical Society of Southern Africa|
|Date:||Jun 1, 2014|
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