ScopeX 2017

For those of you who have never been to ScopeX or even considered going or, worse still, never heard of it, you really need to do something about it. On 16 September, the 16th annual ScopeX event will be held at the Military History Museum in Johannesburg.

This is ASSA’s premier outreach event, so please remind all friends, family, colleagues, etc. who may be interested, to not only come but to also pass on the news within their sphere of influence. Full details can be found on the website: – PDF flyers and posters can be downloaded from the front page.

There is a full programme of interesting lectures, exhibits, and activities, suitable for people of all ages. The museum is great for a family outing, as are the Zoo next door and the Zoo Lake park around the corner. The evening star party (weather permitting) is also very popular.

To all the amateur telescope makers, astrophotographers and observers, please bring examples of your work to display. Even if you have shown the stuff before, remember that there are always newcomers who have not seen it, and others would like to see it again. Work in progress, no matter how humble, is just as valuable to exhibit as a finely finished product, so that people can understand the process and get ideas. You may even win a prize for your efforts!

Check out the excellent range of items to be won in the raffles. Given the limited number of tickets, your chances are really good.

The ScopeX advertisement.

The Begemann Binocular stand: Saturday 19th August 2017.

At the February 2017 Southern Star Party (Go here to read more about this event) Deon and Ronelle Begemann unveiled their binocular stand.  It is basically the standard parallelogram design but it is very affordable, very easy to put up and it works superbly well and would make an affordable addition to any astronomy enthusiast’s equipment. This is a photo review of the apparatus and for more details and a price, you must contact Deon directly.

These are Deon’s contact details.
This is the whole package which comes in these two handy carry bags. It is not a small piece of equipment as can be seen. The main portion, consisting of the tripod and parallelogram-mount, is in bag A. Bag B contains the counter balance chain as well as various other small essentials.
The contents of Bag-B; The counter balance chain and four parts of the binocular mounting system.
The actual apparatus and its tripod.
The tripod and its three struts. The three struts come in the small bag and that is inserted between the tripod’s legs when stowing everything away.
The assembled tripod with the tree stabilizing struts in place.
TOP: This is the head of the tripod with the bolt and wing nut to hold the rest of the assembly in place. BOTTOM: The parallelogram assembly mounted on the tripod head.
TOP: The struts for the tripod are held in place by wing nuts. CENTRE: One leg of the tripod with a strut fixed on either side. BOTTOM: The tree struts, which hold the tripod’s legs firmly in place.
TOP: The end-view showing the position where the binoculars will be mounted. BOTTOM: Side view of the binocular mounting head.
TOP: The battery holder and switch for the LED-assembly. BOTTOM: The LED is in this hole and is intended for use at night to warn people moving around that there is an obstacle.
TOP: This threaded rod with the two nuts forms an integral part of the counter balance system. BOTTOM: The counter balance chain attached to the threaded rod with two carabiner clips.  By adjusting the position where this chain hangs on the threaded rod one creates an effective counter balance for the binoculars at the other end of the assembly.
LEFT: Without either binoculars or counterweight attached the assembly looks like this. RIGHT: With only the counterweight chain attached the cleverly designed leg at this end comes into play. By supporting the counter weight-end it prevents the binocular end from lifting up and making the mounting of the binoculars difficult.
TOP: This assembly will hold the binoculars in place. The threaded rod on the right-hand side is used to adjust the position of the binoculars when viewing. CENTRE: The binoculars rest on the blue bar and the screw, which can be seen protruding from the metal strip in front of the bar, screws into the binoculars. BOTTOM: This handle is used to adjust the angle of the binoculars when viewing. NOTE:  All these components were in bag-A with the counterweight chain.
TOP LEFT: This would normally be the view from below the mounted binoculars. TOP RIGHT: Side view of the mounted binoculars. BOTTOM LEFT: This would normally be the top view of the mounted binoculars. BOTTOM RIGHT: This is the view from the eyepiece end of the binoculars and now the handle for adjusting their angel can clearly be seen in its correct position.
TOP: View from the front of the mounted binoculars. BOTTOM: View from the side of the mounted binoculars and here the wooden handle that has to be attached to the rod for adjusting the tension of the angle control for the binoculars can clearly be seen.
TOP LEFT: View from the front of the complete apparatus and you can see it is beautifully balanced. CENTRE LEFT: The support leg and counterweight chain well clear of the ground. BOTTOM LEFT: These are two washers that were left over. This is a special gift I have that whatever I assemble there are always bits left over. The only surprise, in this case, is that there were only two bits left. TOP RIGHT: The whole apparatus viewed from the counter balance-end with the binoculars at the far end.

 

Outreach by StarPeople for SKA-Africa during National Science Week 2017 at the Iziko South African Museum: Thursday 17th August 2017

Thursday required an early start to beat the infamous N1-traffic and have breakfast at the Rcafe in Long Street (go here to find out more) before starting our day. We left Brackenfell at 05:17, which was actually later than our original ITD of 05:00. ITD? My shorthand for Intended Time of Departure. We were parked in front of Rcafe by 05:45 which meant that the trip had taken us a mere 28 minutes. As soon as the doors opened at 06:00 Lynnette and I went inside to order two much needed Americano’s to start the day properly. What really amazed us was that the owner and staff recognized us the moment we walked in the door and it was a few days more than a year since we’d last been there! Auke arrived shortly after us and ordered his cappuccino. After breakfast, we headed for the Iziko South African Museum (click here for more information) where Benjamin was waiting to unlock the gates for us and set out the traffic cones to prevent vehicles entering our display and observing space in the amphitheatre. The weather was clear but blustery. The wind was, in fact, such a nuisance that I eventually took down and put away the posters, as the frames were being badly scratched every time they toppled over onto the brick paving. Anyway, by 08:00 we were ready to roll and all we needed was a visitor or two, which we soon got.

TOP LEFT: 05:20 and on our way to Cape Town for an early breakfast with Auke at the Rcafe in Long Street. CENTRE LEFT: View from the Gardens with the posters up, telescopes aligned, solar filters taped and waiting for the people. BOTTOM LEFT: View from the Museum with Auke making last minute adjustments. TOP RIGHT: I quite honestly do not know what on Earth I was doing here. Perhaps trying to get an upside down view of our Universe on the poster? BOTTOM RIGHT: This group was from Germany and apparently unable to speak English so the guide worked through a translator. The guide was not wearing a badge and when Lynnette asked him why not, he put his finger to his lips, refused to sign our register and disappeared very quickly with his group.
TOP LEFT: This huge group of highly mobile, extremely vociferous, perpetual motion entities were disguised as pre-school children but I wasn’t fooled. TOP RIGHT: Looking through the telescope seemed to limit them to a single location for a very short period of time before they shot off again at high speed exercising their vocal cords to maximum effect. BOTTOM LEFT: Edward talking to Jay van den Berg, one-time archaeologist and now Karoo Palaeontologist at the Iziko South African Museum, after having been poached by Dr Roger Smith. Nice meeting you Jay. BOTTOM RIGHT: Interspersed among the myriad of short people were teachers and a few parents who seemed to create small islands of order and stability around themselves as they moved around.

Thursday’s are popular school days at Iziko and we had three groups that we managed to convince that they should take a peek at the Sun. There were several other school groups whose teachers waved us away when we invited them to view the Sun. Being a weekday many of our visitors were from outside the country’s borders as most South Africans were hard at work earning an income. Many of the tour guides with the groups declined to let their tourists take a look at the Sun. Their reason was mostly that they had a schedule to keep to and did not have the time. Nevertheless, we had groups from Gabon, Thailand, Hong Kong, France, Netherlands, Israel, and Germany.

TOP LEFT: Auke showing a group the Sun and discussing Solar Physics. TOP RIGHT: An attentive group waiting their turn to look at the Sun with Auke. BOTTOM LEFT: This local couple was far more clued up about things like Space Weather than the average visitor. Always pleasant to talk to people that know enough to ask some testing questions. BOTTOM RIGHT: This visitor conveniently helped himself to a view of the Sun while Edward answered questions in the background.
TOP LEFT: Edward and a group of younger visitors accompanied by a watchful parent. TOP RIGHT: This very well organised primary school visited us with their teachers. It was lovely having such an orderly group. BOTTOM LEFT: A teacher keeping an eye (and ear) on Auke as he talks to a group of learners. BOTTOM RIGHT: Lynnette, with a young person, who was so eager to look at the Sun that he couldn’t wait for the ladder, but stood on the tips of his toes to reach the eyepiece.

It was also nice to have the research staff from the backrooms of Iziko pay us a visit. I was especially pleased to make the acquaintance of Jay van den Berg a palaeontologist on Dr Roger Smith’s staff and Clair Browning the newly appointed Curator of the Karoo Collection.

TOP: Auke with some members of a group that came through in the morning. BOTTOM: Packing up. It never ceases to amaze me that, despite careful planning, there are always things that don’t seem to fit where they were when one unpacked them.

The problem of getting people to sign our visitor’s book was highlighted for the umpteenth time. Many people who viewed the Sun through our telescopes flatly refused to sign the list and some actually became quite agitated when asked to do so. This problem is exasperated when one is busy and you simply do not have time to chase after people and ask them to sign. So, once again, our signature total (288) and counter tally (597) do not agree. I am more convinced than ever that the answer lies in devising a means to automatically count the number of people who look into each telescope’s eyepiece.

Because the Sun appears as a very bland and uninteresting white ball as a result of of the solar filter fitted to Lorenzo, many viewers say it looks like the Moon. So I decided to do some experimenting with filters to make the image more “exciting”. The images were all taken with my mobile and I am afraid that I do not have the world’s steadiest hand, so the photos are not of the best quality.

TOP: The Sun viewed through a 25mm eyepiece on Lorenzo, the 10”Dobsonian. Lorenzo was fitted with a solar filter constructed with Baader AstroSolar™ Safety Film. I think the focus is reasonable for a mobile phone. CENTRE: The same setup as in the first photo but with a Baader Solar Continuum Filter (CWL 540nm) added to the eyepiece and I am clearly struggling more with the focus than in the first photo. BOTTOM: The same setup as in the first photo but with a Meade Series 4000 Filter No 23A added to the eyepiece and here my focus is much better. NOTE: All photos were taken with my Samsung A5 mobile at the eyepiece.
TOP: This is the image of the sunspots for the day as provided by the Solar Dynamics Team with the Earth to give one perspective. I am afraid that between Lorenzo and I we cannot quite manage this. BOTTOM: This is an enlarged view of the sunspots on the bottom image of the previous group of photos. I have flipped the photo so that the layout matches that of the top photo.

 

Outreach by StarPeople for SKA-Africa during National Science Week 2017 at the Iziko South African Museum: Sunday 13th August 2017

Sunday was an almost perfect day for an outreach event in the amphitheater of the Iziko South African Museum (click here for more information) in Cape Town.  Lynnette and I, unfortunately, got there a bit later than we had intended. Auke had almost finished setting up by the time we arrived and we just managed to get Lorenzo setup before the first visitors put in an appearance.

TOP LEFT: All packed up in the new workhorse, courtesy of SKA-Africa (Click here for more information). TOP RIGHT: Snorre putting on his pissed-off-to-be-left-behind act. BOTTOM LEFT: The start of a table cloth on Table Mountain had me a tad worried because once the South-Easter gets going you do not want to be in the amphitheater in front of the Iziko South African Museum with telescopes, banners, and posters. BOTTOM RIGHT: The first group in were Dutch tourists, here gathered around Auke with Lynnette lending a hand.
TOP LEFT: Lynnette and Auke showing a small group the almost spotless sun through Lorenzo the 10” Dobby. TOP RIGHT: Edward, who actually remembered the ladder this time, helping a brightly dressed young lady to look at the sun. BOTTOM LEFT: Rose’s Egyptian geese and this year’s batch of young ones on a morning stroll. In 2009 they were officially declared a pest in the United Kingdom. (Click here for more information) BOTTOM RIGHT: Auke in a serious discussion with a small group of visitors.

While we were setting up, Benjamin, the museum security guard, came round to say hello and put out the traffic cones thereby preventing people from attempting to park among the telescopes. Throughout the rest of the day, he appeared every now and again, keeping a watchful eye on the ever present idlers and strollers who often have less than honest intentions.

In the background are our banners; the SKA banner is partially hidden on the left, with the striking StarPeople banner in the middle and the impressive Sun banner on the right. In the foreground, three guests try out the solar viewing glasses.
TOP LEFT: Three guests heading for the museum after Lynnette showed them the sun and Auke taking a break in the background. TOP RIGHT: Auke and a small group of tourists at the telescope. BOTTOM LEFT: Edward, Lorenzo and a young astronomy enthusiast. BOTTOM RIGHT: The museum building reflected in our new 4×4 vehicle supplied by the SKA.
TOP LEFT: The very striking StarPeople poster designed by Auke and beautifully framed thanks to Dirk’s donation of the frame. TOP RIGHT: Edward in conversation with a group that eventually showed interest in attending the next Southern Star Party too. BOTTOM LEFT: Late afternoon visitors and you can see the shadows of the trees encroaching on our viewing territory. BOTTOM RIGHT: A bee that seemed to have trouble flying for more than a short distance at a time was rescued after almost being stepped on.

We had a steady stream of visitors throughout the day. However, every time a tour group passed through the activity around the telescopes peaked and required all hands on deck. It was really a pity that, other than one lone sunspot (2670) which was about to disappear over the rim of the sun, there was no activity to be seen. I found the overseas visitors far more aware of astronomical matters than the South Africans. Having said that though, Lynnette had one local three-year old who knew the names of all the planets and, when quizzed, also knew which planet was the smallest and which was the largest!

TOP LEFT: Lynnette and I would love to take this vehicle out on the back roads up in the Northern Cape. TOP RIGHT: Auke pointing out matters of astronomical interest on some of our A3 posters mounted on hardboard. BOTTOM LEFT: Lynnette, Lorenzo and a couple of enthusiastic visitors. BOTTOM RIGHT: Lynnette urging a family to buy the Sky Guide (go here to find out more) and become clued up amateur astronomers.

All in all, it was a very pleasant day with the wind dying down by mid-morning and the few clouds that there were never really posing a serious threat to our solar observing. One of the problems, that occurs every year, with this kind of event is the effort to get people to sign our visitor’s register. Some people just refuse point blank and others again refuse to give contact details. During periods of high activity, when everyone is manning a telescope, we also lose signatures because there is nobody available to monitor if visitors sign the register or not. Our counters, as is usual, gave far higher figures than the number of signatures but, because one is busy with visitors, one probably also misses visitors with the counters. Maybe we should get some inventive person to install a counter at the eyepiece that counts when people look into it.

TOP: Everything cleared up and packed away as we prepare to head for home. BOTTOM: The Tygerberg against a clear blue sky and the unusual treat of having the N1 relatively traffic free.

 

Outreach by StarPeople for SKA-Africa during National Science Week 2017 at the Brackenfell Public Library: Thursday 10th August 2017.

Thursday was a very different kettle of fish at the Brackenfell Public Library compared to Tuesday. No sun, lots of low gray clouds and a cold, blustery north-westerly wind. We implemented plan-B and moved inside, as discussed previously with the library staff.  Amanda helped us get organized in the library hall and pointed out the spots in the foyer we could use for posters and A-frames.

Despite putting up notices inviting people to come and flummox us with their astronomy queries we had the grand total of two visitors the entire morning. Those two were actually old friends, Billy and Halcyone Brits who had heard that we would be there and come specially to see us.

TOP LEFT: The entrance to the Brackenfell Public Library against a cloudy background. TOP RIGHT: One of our signs attempting to entice interested persons into our Astronomical clutches. BOTTOM LEFT: Edward and the small group of learners at the start of the afternoon’s talk. BOTTOM RIGHT: Auke holding the attention of some learners.

The afternoon wasn’t much better as the cold weather seemed to have thinned out the number of learners quite drastically too. Following Lynnette’s suggestion, we gave a talk to the small group that was there.  This talk was one we had previously compiled with input from the staff at Boesmansrivier Primary School for use with their learners. The talk was quite enthusiastically received by the learners present. Their enthusiasm was, in fact, at times more than just a bit rowdy!

TOP LEFT: One of the slides in the talk which Edward uses to emphasize the negative effects of light pollution. TOP RIGHT: The age-spread of the learners in the group was quite large. BOTTOM LEFT: Auke discussing an issue with a small group of the learners. BOTTOM RIGHT: The talk actually held the attention of the learners remarkably well.

Murphy saved his final trick for the end of the day. When we tried to start the Vito and leave for home it refused point blank. Not too much of a problem as I had a spare battery at home.  We phoned a friend who nipped round, picked me up and dropped me at home. I picked up the spare battery, popped it into the boot of the Polo, and headed back to the Library where Lynnette was waiting.

Murphy now played his next trick. The new battery was about one millimeter too large to fit into the battery compartment of the Vito and the battery leads were too short to reach the battery in any other place outside the battery compartment, where we would be able to shut the door. Lynnette and I quickly ran through plans C to Y before I hit on plan-Z. I connected the spare battery and, while I was holding it, Lynnette started the Vito. Lynnette then kept the engine running quite fast and I disconnected the spare battery, connected the old battery, and slid that into the battery compartment. It all worked perfectly without any shocks, sparks or short-circuits. I was very careful not to throw a clearly crestfallen Murphy the middle finger as he has a very long memory.

Lynnette drove the Polo home and I followed in the Vito, finally bringing the day to a close.

Outreach by StarPeople for SKA-Africa during National Science Week 2017 at the Brackenfell Public Library: Tuesday 08th August 2017.

We set up just outside the entrance to the Brackenfell Public Library. The forecast said it would be a sunny day so we also put up our gazebo and decorated that with some of our banners. The banners look nice, provide added wind protection, make the gazebo sturdier and also help prevent uncontrolled access. Sunelle, Lötter and her staff used the material we gave them, predominantly from our own stocks, to put up displays in the entrance foyer and several other parts of the library

The Vito all loaded and ready to go.
LEFT: The cover of the mission MeerKAT booklets received from SKA-Africa. RIGHT: Part of the static display set up inside the library by the very helpful library staff.
TOP LEFT: Our setup as seen from the parking area by visitors approaching the front door of the library.  TOP RIGHT: Our setup as seen from a different angle in the parking area. BOTTOM LEFT: Lorenzo and I getting our dose of Cape Winter sunshine. Other than the learners we also had many people bringing young children to the library show interest. BOTTOM RIGHT: The flow of viewers fluctuated quite a lot during the morning but during the afternoon had much more activity and in a fairly steady stream.

As we have experienced in the past it takes a lot of effort to get the public to come and take a look, despite the fact that the telescope was very visible, as were our A-frames and pull-up banners. One has to resort to accosting people, as they approach the entrance and begging them to come and take a peek at the Sun and its lonely sunspot.

TOP LEFT: An enthusiastic group around Lynnette’s table.  TOP RIGHT: Some of the younger learners had the usual problem of not knowing which eye to shut when looking into the eyepiece. BOTTOM LEFT: Edward getting the sun into the eyepiece for the next viewer. BOTTOM RIGHT: Some of the older learners asked questions and while many of the others looked and did not show much interest.

This all changed dramatically during the afternoon when the schools closed; we were almost inundated!  The Library serves as a focal point for learners whose parents are at work as they also use the library hall to do their homework. The youngsters from the apartments across the road from the library simply use the library and environs as an entertainment area. For the latter group, our presence was a welcome added attraction to their normal routine.

TOP: The morning was generally slow with older adults coming in ones and twos.  BOTTOM: Edward taking a break during a quieter period in the afternoon.

Thanks to the sunny weather and the eager learners it was eventually quite a pleasant and productive outing.

Our spot, all cleared up in the late afternoon sun and waiting for our return on Thursday.

 

Partial Lunar Eclipse: Monday 07th August 2017

Lynnette and I set up Lorenzo in the rooftop parking area of the Family Pick & Pay on the corner of Old Paarl Road and H.O. De Villiers Street in Brackenfell. The event had been advertised via local social media sites and announcements were also made by the store manager during the course of the evening.

This graphic was borrowed from a Facebook posting by Willie Koorts of the SAAO, who is well known for his participation in the Radio Sonder Grense radio programme “Sterre en Planete”, which is broadcast every Sunday evening.
The photo was taken by Lynnette using her Samsung A5 mobile on the 20mm eyepiece of the 10” Dobsonian.
TOP: The Vito as the backdrop to our StarPeople pull-up banner.  BOTTOM: Edward on the left with Lorenzo just making it into the photo and Esther and Sewes from the local Neighbourhood Watch resplendent in their “Glow-as-much-as-you-can” bibs.
TOP: Edward and Esther discussing some serious astronomy.  MIDDLE: Two guests, all the way from Bellville, signing our attendance register.  Strange that many people just flatly refuse to do this.  BOTTOM: This group stayed for quite a while and showed a great deal of interest.

The turnout was disappointingly low but the few people that did turn up were very enthusiastic, which compensated for the poor attendance.

Light Snow at Leeuwenboschfontein

On the 16th of July 2017 Leeuwenboschfontein had a light sprinkling of snow and the staff there were kind enough to send us some photos.

Leeuwenboschfontein is situated in the Western Cape on the very western edge of the Little Karoo at an altitude of just over 1 000m.  It is a fantastic place for stargazing and observing and was the venue for the thirteenth Southern Star Party held in February 2017 (more about that event can be found here).  We are already planning the 14th Southern Southern Star Party scheduled for October 2017.

Make sure you are there.

A view across the dam behind the administration office toward one of the camp sites and the Swartberg in the distance.
Administration office on the left and the back of De Oude Opstal on the right
This is the lovely green lawn in front of De Oude Opstal and in the background, you can see the roof of the large shed where we have the talks. This lawn becomes the telescope area during a Southern Star Party.

Outreach & Guiding for a National Science and Technology Forum group (NSTF Brilliants) to the Square Kilometre Array (SKA) and the Southern African Large Telescope (SALT): Friday 23rd to Monday 26th June 2017.

Anja Bruton, the Science Promotions Coordinator at SKA Africa, approached StarPeople to accompany the NSTF Brilliants group (http://www.nstf.org.za/youth/brilliants-programme/) on the tour to the SKA and SALT and we jumped at the opportunity. Anja and Dimpho would fly to Kimberly to meet up with Jansie Niehaus and Wilna Eksteen from the NSTF (http://www.nstf.org.za/) and a group of students, chosen for their exceptional performance in the 2016 Matriculation exams; specifically in the Science paper. This group would fly down from Gauteng and, after a day’s sightseeing in Kimberley, they would tackle the long journey to Carnarvon in two Quantums on Saturday the 24th. They would also be accompanied by two photographers who were tasked with documenting the trip.

Lynnette, Auke, Snorre and I would leave Cape Town for Carnarvon (https://en.wikipedia.org/wiki/Carnarvon,_Northern_Cape) early on Thursday the 23rd and book in at the Lord Carnarvon Guest House. Anja and the rest of the group were scheduled to arrive shortly after lunch on Saturday and on Saturday evening StarPeople were to present a stargazing session at Klerefontein, the SKA’s operational base about 15 km outside Carnarvon. On Sunday morning the group would visit the SKA site itself and after that, e would depart for Sutherland. On Sunday evening there was to be stargazing session at the SAAO’s Visitor’s Centre and on Monday morning we would tour the SAAO facilities on the hill before heading for Cape Town.

However, as Robert Burns once said “The best laid schemes o’ mice an’ men / Gang aft a-gley.” First of all, Auke had to pull out because of domestic complications. Then the car hire company notified us that the vehicle we required could only be delivered on Friday morning and not on Thursday afternoon as requested. This, of course, scuppered our 05:00 departure plan, but Lynnette and I made sure that we had everything packed and ready to load by 08:00 when the vehicle was scheduled to arrive. However, it only arrived at about 08:30 and, when it did arrive, it was petrol and not diesel driven as had been requested. Disaster! Petrol-driven vehicles are not allowed access to the SKA site because their spark plugs generate interference for the radio telescope. It is more than 600 km to Carnarvon and we had to be there before dark. We also still had to load the vehicle so, if we sent it back and insisted on a diesel driven one, there was no chance of reaching Carnarvon before dark. We signed for the vehicle, finished loading in record time and at 09:40 we set off for Carnarvon.

TOP: The hired Hyundai H1 with the StarPeople door magnets.  CENTRE: Entering Malmesbury.  BOTTOM: Passing Moorreesburg on the N7.

The journey was long but uneventful. We stopped for petrol and Lynnette’s packed lunch in Vanrhynsdorp (https://en.wikipedia.org/wiki/Vanrhynsdorp) after 290 km. We then stopped halfway up the spectacular Vanrhyns Pass to take pictures. The original pass was constructed in 1880 by Thomas Bain and climbs almost 600 m from the Knersvlakte to its summit, situated at just over 800 m, which is about the same as the top of Du Toitskloof pass. The pass has an average gradient of 1:15 with the steepest section being 1:12.

TOP: Looking West from Piekenierskloof Pass toward the northern end of the Piketberg.  CENTRE: Citrusdal in the distance against the backdrop of the Cederberg with Cederberg Sneeukop just left of centre.  BOTTOM: The turn-off to Clanwilliam and this rebuilt section of the N7 is a pleasure to drive.
TOP: Stop and Go delay due to the reconstruction of the bridge across the Olifants River.  CENTRE: The light coloured patches on the hill in the background are called Heuweltjies and their origin is a much-debated topic. Go to any one of the following links to read up on them. (1. https://www.revolvy.com/main/index.php?s=Heuweltjie) (2. https://en.wikipedia.org/wiki/Heuweltjie#cite_note-7) (3. http://www.sajs.co.za/sites/default/files/publications/pdf/SAJS%20112_1-2_Cramer_Research%20Article.pdf) (4. https://www.infona.pl/resource/bwmeta1.element.elsevier-ab969e23-2c87-36b0-a144-1c5ed9ebd6af) BOTTOM: Vanrhynsdorp and the cliffs of the Matzikamma mountain range. Maskam lies at the eastern end while Gifberg is on the western edge. These mountains form the western boundary of the Great Escarpment.
TOP: Approaching the Knersvlakte on the R27 and in the distance the edge of the Great Escarpment.  2nd FROM TOP: Vanrhyns Pass which takes the R27 up to the top of the Great Escarpment is visible in the distance.  2nd FROM BOTTOM: The R27 begins the ascent of the pass.  BOTTOM: Up we go around one of the many fairly sharp bends in the road up the pass.

Shortly after Vanrhyns Pass, we passed the turnoff to the Oorlogskloof Nature Reserve (here is a Wikipedia link http://www.footprint.co.za/oorlogskloof.htm ) with its spectacular glacial floor, but there was no time to visit that on this trip. The reserve is situated just west of Nieuwoudtville (http://www.nieuwoudtville.com/the-treasure/). Next was Calvinia the main town of the Hantam region (https://en.wikipedia.org/wiki/Calvinia) with its extra outsize red post-box and, 230 km after Vanrhynsdorp, we reached Williston (https://en.wikipedia.org/wiki/Williston,_Northern_Cape), where we made a brief stop for another light snack and to answer a call of nature, before tackling the last 125 km to Carnarvon. Time constraints had prevented us from visiting the Langbaken cheese farm (http://karoospace.co.za/cheesemakers-upper-karoo/) south of Williston, but we will save that for another day.

TOP: View back over the Knersvlakte toward the West Coast and the distant South Atlantic Ocean.  2nd FROM TOP: View southeast past a mass of protruding sandstone in the direction of the Oorlogskloof Nature Reserve.  2nd FROM BOTTOM: Steep cliffs of Table Mountain sandstone group rise above the road.  BOTTOM: A very large red flower post-box in Calvinia.
TOP: The R63 stretches out ahead of us as we approach Williston.  2nd FROM TOP: The shadow of the Earth and the pink layer of the Venus Girdle over Carnarvon as we approach on the R63.  2nd FROM BOTTOM: Entering the outskirts of Carnarvon.  BOTTOM: Our destination the Lord Carnarvon Guest House in Carnarvon.

On the last stretch, we had to push it a bit and reached Carnarvon in the gathering dusk at 17:45, where we reported to Pieter Hoffman at the Lord Carnarvon guest house in Daniel Street (https://www.carnarvon.co.za/lcindex.htm). This building was the Officer’s Mess during the Anglo-South African War and he has done a magnificent job of restoring it. We unloaded, got Snorre settled in, and walked round to Lord’s Kitchen in Victoria Street (https://www.tripadvisor.co.za/Restaurant_Review-g4226745-d8743616-Reviews-Lord_s-Carnarvon_Northern_Cape.html), also run by Pieter, for supper. After supper, we walked back to the Lord Carnarvon and had the amusing experience of being escorted by a police vehicle because “nobody walks around Carnarvon in the dark”.  This remark struck us a rather odd considering the fact that there were quite a few other local people in the streets.

TOP: Our very well appointed accommodation in the Lord Carnarvon Guest House.  2nd FROM TOP: Snorre making himself at home on his red blanket which we always put over the bed wherever we stay. Although he never, or hardly ever, sleeps on our bed at home, he doesn’t miss the opportunity to do so when we are away from home.  2nd FROM BOTTOM: Interior of the front section in Lord’s Kitchen.  BOTTOM: Outside view of our room in the guest house.

On Saturday morning, after breakfast at the Lord Carnarvon, Lynnette, Snorre and I took to the streets to do some house hunting in case we should decide to move to Carnarvon. The results of this expedition were rather disappointing as we soon discovered that, like many small country towns in South Africa, the homeowners wanted lots of cash for the property that was, in our opinion, worth a lot less. The other aspect which surprised us, even though Anja had warned us about it, was the negative sentiment toward the SKA project and the amount of disinformation circulating in the town. This varied from stories that farmers were being chased off their farms without compensation or that farms were being confiscated in order to distribute the land to previously disadvantaged persons, and even that townsfolk were to be evicted so that four blocks of houses could be knocked down to build a college. We also came across an openly hostile sign in a back yard in Kidd Street. Most obvious was the fact that almost everyone we spoke to had no bloody clue what the SKA was, or what it was about.

TOP: Snorre enjoying our slow exploration of Carnarvon.  2nd FROM TOP: Some locals on the outskirts of Carnarvon.  2nd FROM BOTTOM: Victoria Street and Lord’s Kitchen with the Adjacent Lord Carnarvon Hotel.  BOTTOM: Sign in the back yard of a house in Kidd Street which we found to be indicative of the attitude of many Carnarvon residents we spoke to.

Shortly before 16:00 Anja let us know they had arrived and were having a late lunch at Lord’s Kitchen. We popped around and Anja introduced us to the group. After the meal the group dispersed to their various rooms and Anja, Dimpho, Lynnette and I set off for Klerefontein, the SKA’s operational base, to set up Lorenzo for the stargazing later that evening. Mission accomplished we headed back to town to collect all our warm gear and have supper. After supper, the five vehicle cavalcade made its way back to Klerefontein. On a hill southeast of where we were situated was the large 7,6 m dish of the C-BASS radio telescope (https://www.ska.ac.za/science-engineering/c-bass/) catching the last rays of the setting sun as it patiently toiled away sweeping back and forth to map the radio sky in the 4,5-5,5 MHz frequency range. The C-BASS dish, recently moved from Hartebeeshoek (http://www.hartrao.ac.za/) to Klerefontein, is the southern component (the other telescope is in California) of a project to produce a microwave (short-wavelength radio) radiation map similar to the one produced by the European Space Agency’s Planck satellite (https://en.wikipedia.org/wiki/Planck_(spacecraft)), but at longer wavelengths than Planck. C-BASS will also measure the polarization of the radiation.

Anja split the students into two groups for the planned activities. One group stayed with Lynnette, Lorenzo and I to do some stargazing. The other group went inside to participate in Skype Q&A session with Jim Adams, Deputy Chief Technologist at NASA (https://solarsystem.nasa.gov/people/adamsj).The Milky Way was magnificent and drew many Ooh’s and Aah’s from the group. I did a basic what’s-up-tonight and then kept talking while Lynnette operated Lorenzo. There was no Moon but fortunately, Jupiter and Saturn were nicely placed and we could also show them a selection of the other well-known objects. After about an hour the groups changed around and Lynnette, Lorenzo and I repeated our earlier performance. Once we had done with the second group, it was packing up time and then back to town for a hot shower and some much-needed sleep.

Sunday morning at 06:15 it was breakfast time at Lord’s Kitchen and, after collecting our packed lunches, it was all aboard for the trip out to Klerefontein where Anja gave us a Health and Safety briefing and had us all fill in indemnity forms. During the briefing, the emphasis was placed on the mayhem electronic devices caused for the radio telescopes. Mobile phones, which all had to be switched off, were a prime source and even my hearing aid’s hands-free device, that uses Blue Tooth, had to be switched off. After all, this had been sorted out, our motorcade tackled the more than 70 or so kilometers out to the actual SKA site. Large sections have already been tarred, but there are still fairly long sections that are very rough and dusty. Lynnette and I had to leave our petrol driven vehicle with Snorre in it just inside the checkpoint at what used to be the Meysdam farmhouse and continue with Anja and Dimpho in their vehicle. Snorre was quite safe, with enough fresh air, water and food to keep him busy till we get back. We made sure that the vehicle would be in the deep shade while we were away too.

TOP LEFT: Coffee was clearly a priority for most of the group.  TOP RIGHT: They came in by drips and drabs.  BOTTOM LEFT: André, one of the drivers, looking most inquisitive.  BOTTOM RIGHT: Leftovers tell the tale of what was popular and what wasn’t.
TOP: A quiet Victoria Street at 07:20.  CENTRE: Entering Klerefontein with the C-BASS dish on the hill in the distance.  BOTTOM: A dusty section of the road out to the SKA site.

Our first stop was the very impressive, half underground, Karoo Array Processor Building. Placing the centre below ground level was essential to minimize the amount of interference from the computers. In addition to being below ground level, the whole installation is housed inside a huge Faraday cage (https://en.wikipedia.org/wiki/Faraday_cage). It is ironic that a radio telescope, which cannot function without massive computer support, also experiences its most annoying interference from computers. It was while touring the Processor Building point that I realized that, if I had simply put my phone on Airplane Mode, I could have brought it with me and taken photographs. Some mothers are just unfortunate to have very dense children! Our next stop was the huge, hanger-sized building where the MeerKAT dishes are assembled. It is only when one stands next to one of these huge constructions lying flat on the floor that one really gets an idea of their overwhelming size. Needless to say, at this point, I mentally administered several more resounding kicks to my posterior for not having anything to take pictures with. After completing this part of the tour it was back into the vehicles for the drive out to the telescopes.

The first stop was the KAT-7 dishes (http://www.ska.ac.za/) where all but one pointed south, collecting data on some unseen object light years away in a distant part of the Universe. KAT-7 was a precursor engineering test bed for the larger MeerKAT array and also served as a demonstration of South Africa’s technological ability when the bid for the Square Kilometre Array (SKA) was submitted. However, KAT-7, the first radio telescope ever to be built with a dish consisting of composite material, is also a science instrument in its own right. Each 12-meter dish is fitted with a prime focus receiver and a Stirling pump cooling unit that supplies the cryogenic cooling to keep the electronics at 75 K. The total collecting area of the seven dishes is about 2000 m2 and they function in the 3 to 30 cm wavelength range at frequencies between 1 200 and 1 950 MHz. KAT-7’s minimum baseline (shortest distance between two dishes) is 26 m and the maximum baseline (longest distance between two dishes) is 185 m. These seven dishes will eventually be decommissioned as science instruments when their successors, the MeerKat Array, comes online and be made available for serious amateurs.

Then we were off to find a MeerKAT dish (http://www.ska.ac.za/) that was positioned in such a way that it would be easy to photograph, which wasn’t easy because, despite the fact that they were lots of them, they were all facing in different directions. It really is an impressive sight, seeing these dishes scattered across the Karoo veldt against the backdrop of the low, dolerite topped hills that surround the area, with the dolerite providing a natural radio screen for the telescopes. Considering that only half of the MeerKAT dishes have been erected so far, one can only imagine what a spectacle it will be when all 64 MeerKAT dishes have been completed. The final Karoo Array Telescope or KAT will definitely be a must-see destination and a breathtaking spectacle for all who visit it. MeerKAT will eventually form the core of the KAT radio telescope array. These 13,5m dishes differ from those of KAT-7 in that they use an offset Gregorian configuration for the placing of the secondary dish and the receivers. Each dish is equipped with three receivers; 0,58 – 1,015 GHz, 1 – 1,75 GHz and 8 – 14,5 GHz. The MeerKAT minimum baseline is 29 m and the maximum baseline is 8 km.

Both KAT-7 and MeerKAT are entirely South African conceived, funded and built enterprises and, even after the construction of the KAT, which has multiple international partners, these two installations will remain entirely South African.

Our next stop was the Hydrogen Epoch of Reionization Array (HERA) (http://www.ska.ac.za/) which is the simplest construction imaginable and is the successor to the Precision Array for Probing the Epoch of Reionization (PAPER). PAPER has 128 antennae situated at the SKA site and 32 antennae situated in West Virginia in the USA. HERA is an American, British and South African collaboration that will eventually have 331 antennae of 14 m each at the SKA site. The existing PAPER installation will be moved to a location slightly west of the HERA installation and eventually decommissioned when HERA is fully operational. Whereas KAT-7, MeerKAT, and KAT are multipurpose installations HERA has only one fixed goal; it is going to probe back into time to try and find that moment when the very first stars switched on to light up in the Universe. In the process, it will produce a three-dimensional map of the universe during that specific period using radio waves in the 100-200 MHz frequency range. This project is the radio astronomy equivalent of the Laser Interferometer Gravitational-Wave Observatory (LIGO), and when they succeed, this project could very well be in line for a Nobel Prize. The antennae are fixed in one position, pointing straight up at the sky and have no moving parts, which greatly reduces the cost of the installation. What makes this project remarkable is that it is constructed with materials bought off the shelf in a local hardware store by people from the local community of Carnarvon who have been trained by SKA scientists. The big dishes of KAT-7 and the even bigger dishes of MeerKAT look like science instruments. HERA, however, looks like an inverted chicken coop or perhaps some sort of landscape art and not very scientific at all.

We went back to the Processor Building to enjoy our packed lunches and, while there Lynnette noticed that one of the Quantums had a flat tyre, necessitating a wheel change. After lunch, Anja and Dimpho dropped Lynnette and I off at Meysdam to pick up our vehicle and then we all traipsed back to Klerefontein where Anja and Dimpho changed vehicles before we all drove back to Carnarvon to refuel. Lynnette and I had done that the previous evening so we just hung around until the whole convoy was ready to start the long journey to Sutherland, which Anja had elected to do via Loxton (https://en.wikipedia.org/wiki/Loxton,_Northern_Cape). The just under 70 km from Carnarvon to Loxton was a breeze on a nice tarred road but then came the long 100 km grind on the R356 gravel road to Fraserburg (https://en.wikipedia.org/wiki/Fraserburg). We had been contemplating a visit to the palaeosurface at Gansefontein, just outside Fraserburg, but time was against as; seriously against us. We had hardly left Fraserburg when the sun set and, as it got darker, driving became more and more difficult. The 110 km stretch to Sutherland (https://en.wikipedia.org/wiki/Sutherland,_Northern_Cape) was going to take much, much longer than planned and our stargazing appointment at the SAAO site (http://www.saao.ac.za/about/visting/sutherland/) outside Sutherland had to be canceled. Because Lynnette and I were the last car in the convoy, we collected all the dust from the four vehicles ahead of us. This forced us to fall back more than a kilometer behind the fourth vehicle before we had a clear view of the road ahead.

We all made it safely to Sutherland and, while the majority of the group was booking into the Sutherland Hotel (http://www.sutherlandhotel.co.za/accommodation.php), Lynnette, Snorre, Anja and I as well as the two drivers of the Quantums, booked into Kambro Kind Guest House, where we were welcomed by Juanita Hutchings. Once booked in we went back to the Hotel where we had a typical Karoo supper consisting of meat, meat and more meat with a few vegetables right at the end of the buffet table.  It is just a pity that the hotel did not think of having a nice fire going in the dining area on such a cold evening.

After supper Lynnette and I, Lorenzo, Anja, the photographers and several students drove out to Middelfontein to do some stargazing (http://www.roomsforafrica.com/establishment.do?id=13879&gclid=Cj0KCQjws-LKBRDCARIsAAOTNd6cUH9fdKlh5bbYksnV0F5D-BQPK4kMRrO8IdxP7D_a6uSOZX_UQX8aAoUUEALw_wcB). The photographers were spending the night on Middelfontein, but the rest of us would have to drive back to town to get some sleep. The right side sliding door on our vehicle, which had been playing up since the previous day went on strike when we started unloading. It first refused to open and then, when we forced it to open, it refused to shut without the use of considerable force and, once shut, it refused to open again so we left it shut. Then the courtesy light inside the door which was supposed to only go on when the door was open, decided it wanted to be on even when the door was shut. A resounding thump on the outside of the door convinced the light to go off and stay off. Once that was sorted out we could get round to the stargazing which was a presented in the same format as on Saturday evening at Klerefontein and, once again, worked very well. So well, in fact, that Anja had to chase us all off to bed around midnight.

On Monday morning Lynnette and I packed up before breakfast and, true to Sutherland’s reputation of being very cold, the windscreen of our vehicle was thickly frosted over and the fishpond had a layer of ice over it, thick enough to walk on. After breakfast at Kambro Kind, everyone gathered at the Hotel before departing for the SAAO site where the group spent some time examining the displays in the Visitor’s Centre before Anthony Mitas took us under his very capable wing and shepherded us up the hill to start our tour at the Southern African Large Telescope or SALT (http://www.saao.ac.za/science/facilities/telescopes/salt/). SALT is an international collaboration between South Africa and several overseas partners and is operated as a separate research entity on the SAO site.

TOP LEFT: In Sutherland, you can stand on your fishpond – sometimes.  CENTRE LEFT: The group gets kinky necks as Anthony points up.  BOTTOM LEFT: The SALT mirror.  RIGHT: A section of the beautiful quilt in the foyer of the Visitor’s Centre.
LEFT: SALT all the way to the dome.  RIGHT: SALT against the backdrop of the blue Karoo sky and some wispy clouds.

Anthony presented a most comprehensive and informative talk to the group and, to everyone’s delight, arranged to have the 32-ton behemoth raised on its air cushions and rotated for us. After SALT we went to the 1,9-meter telescope. This is the second largest optical telescope in South Africa and, as the Radcliffe Telescope, it used to be housed in Pretoria but uncontrolled light pollution chased it south in the mid-1970’s (http://assa.saao.ac.za/sections/history/observatories/radcliffe_obs/). It has since acquired new instrumentation designed and built by SAAO-staff and still has many years of valuable scientific life ahead of it. At the telescope, we were met by Dr. Potter, a senior astronomer on the SAAO staff. Dr. Potter talked most informatively about the telescope and his own work as well as the other projects being conducted on the telescope. He also demonstrated how easy it was to operate the telescope, especially after the installation of modern electronic control systems, and showed the group around the control room as well.

After saying goodbye to Dr. Potter and Anthony, we stopped off in Sutherland to refuel and then made a beeline for Cape Town where the group had an 18:00 appointment at the SAAO headquarters in Observatory. We made one stop at the Veldskoen Farm Stall and said our final goodbyes before splitting up.

TOP: Salpeterkop the extinct 65 million-year-old volcano. The container on the left is the Property of the South African National Space Agency (SANSA) and was recently opened along with the German Aerospace Centre’s dome (DLR) (http://www.sansa.org.za/spacescience/resource-centre/news/1622-another-eye-towards-the-sky-unveiling-south-africa-s-optical-space-research-laboratory?platform=hootsuite). The white pillar on the right used to carry a German site testing telescope – I think! CENTRE: A very bored traveling cat called Snorre.  BOTTOM: Descending the Hex Pass.

My only regret is that with the group split over several vehicles it was impossible to do any guiding while en route. Although we considered stopping the vehicles at points of interest, it would not have been practical from a safety point of view. Time constraints, which played an important role during the trip, virtually canceled the possibility of additional stops even if safety had not been an important consideration.

TOP: A scene north of the R27 as one approaches Calvinia.  2nd FROM TOP: Those five crumbed mushrooms were quite good, but they cost R9 each at Lord’s Kitchen!.  2nd FROM BOTTOM: The two crumbed pork chops served by Lord’s kitchen were probably the largest I have ever been served in a restaurant and they were also probably the most tender and juicy ones too..  BOTTOM: It’s a good thing we didn’t stay too much longer in SALT or there would have been some very stiff necks the next day.

I will post more photos at a later stage as they become available from other people who were on the trip as well as the two official photographers.

Unihedron Sky Quality Meter, Error Identification and Elimination

Background

This Unihedron Sky Quality Meter (Ser. No. 5739 / Mod. 2.17) has been used over a six-year period at various venues in South Africa. I noted that the first four to six readings in every series of measurements we took drifted lower before stabilizing. My revised operating procedure discards the first four reading in every series and this has virtually eliminated the initial drift of earlier measuring sessions. My results showed and still show inexplicable outliers which have a negative impact on the error profile of the results produced. By mounting the unit on a tripod and making sure it is level and exactly vertical instead of operating it while hand-held, I have reduced the number of outliers but not eliminated them.

  1. Experiment 1.

The results of the first experiment were obtained at Bergwater Lodge (-33°39’47.06″, 20°00’44.13″, 501m) near Montagu. The objective was to see if the readings taken with the Sky Quality Meter at the zenith (0°) and at 30° and 60° down from 0°, toward each cardinal direction varied and, if they varied, by how much. In experiment 1 the meter was hand-held.

  1. Results for Experiment 1.
The readings toward the east (E30°) and West (W30°) were consistently similar and both sets were slightly better (darker) than the zenith readings. The values toward the North (N30°) and south (S30°) were consistently less dark than the East & West readings with the N30° readings slightly better (darker) than the S30° ones. I have no explanation for the outlier in the S30°set.
The readings toward the east (E30°) and West (W30°) were consistently similar and both sets were slightly better (darker) than the zenith readings. The values toward the North (N30°) and south (S30°) were consistently less dark than the East & West readings with the N30° readings slightly better (darker) than the S30° ones. I have no explanation for the outlier in the S30°set.
The E30° readings were darker than either the 0° readings or the W30° ones. The W30° readings were marginally less dark than the 0° values. The values for N30° were quite close to the other values but not quite as dark and S30° was noticeably different and again the lowest (least dark) of the five sets.
The E30° readings were darker than either the 0° readings or the W30° ones. The W30° readings were marginally less dark than the 0° values. The values for N30° were quite close to the other values but not quite as dark and S30° was noticeably different and again the lowest (least dark) of the five sets.
The E60° readings were darker than either the 0° readings or the W60° ones and both sets were darker than the 0° values. The values for N60° and S60° were quite close to the other values but not quite as dark, however, all the different sets were much closer together than in Figures 1 and 2.
The E60° readings were darker than either the 0° readings or the W60° ones and both sets were darker than the 0° values. The values for N60° and S60° were quite close to the other values but not quite as dark, however, all the different sets were much closer together than in Figures 1 and 2.
The E30° readings were darker than either the 0° readings or the W30° ones. The W30° readings and the 0° values are very close to each other. The values for N30° and S30° were also quite close together but, in this case, the N30° values were marginally less dark than the S30° ones.
The E30° readings were darker than either the 0° readings or the W30° ones. The W30° readings and the 0° values are very close to each other. The values for N30° and S30° were also quite close together but, in this case, the N30° values were marginally less dark than the S30° ones.
The W60° readings were now the darkest ones followed by the E60° ones. The 0° readings and the S60° values are hardly distinguishable with the N60° values just slightly lighter.
The W60° readings were now the darkest ones followed by the E60° ones. The 0° readings and the S60° values are hardly distinguishable with the N60° values just slightly lighter.
Depiction of the % difference between zenith (0°) readings and other values.  Zenith values were taken as 100% so negative values indicate series of readings that were higher (darker) than zenith readings.
The depiction of the % difference between Zenith (0°) readings and other values. Zenith values were taken as 100% so negative values indicate series of readings that were higher (darker) than zenith readings.
  1. Discussion of Experiment 1.

The results in Figures 1 to 6 show that the values given by the Sky Quality Meter do differ at the different cardinal points and also at 30° and 60 ° down from the zenith (0°). At both 30° and 60°, the readings were darker toward the west and east than at 0° and less dark toward the north and south.

In order to illustrate the differences more clearly, the Sky Quality Readings were calculated as a percentage of the value obtained for the zenith (0°) and these results are depicted in Figure 7 (above). Here it is clear that W30°, E30°, W60° & N60° readings were consistently darker than the readings at 0° (average -0.4222) while those for N30°, S30°, N60° & S60° were lighter by a larger margin (average 0.8175).

  1. Future Planning.

One set of results is not enough to draw any general conclusions from and I suspect the results will vary from site to site. In all probability, they will also vary from season to season for the same site as the position of objects in the sky changes seasonally. I will select a suitable site and repeat the test at three monthly intervals over the course of one year.

  1. Experiment 2.

The values in the second experiment were obtained at the SAAO Hostel near Sutherland (-32°22’35.29″, 20°48’18.56″, 1703m). I wanted to verify that my Unihedron Sky Quality Meter’s readings were consistent at 0° when the instrument was rotated 90° between consecutive readings around the vertical axis. In experiment 2 the meter was tripod-mounted and the tripod was set to level and vertical using a spirit level.

  1. Results for Experiment 2.
The two sets of south/north (S/N) -readings are consistently darker than the west/east (W/E) -readings. Despite the three outliers, the two sets of S/N-readings lie quite close together as do the two sets of W/E readings.
The two sets of south/north (S/N) -readings are consistently darker than the west/east (W/E) -readings. Despite the three outliers, the two sets of S/N-readings lie quite close together as do the two sets of W/E readings.
  1. Discussion of Experiment 2.

From these results, it appears that the Unihedron Sky Quality Meter I use does, in fact, give different readings in the two 90° orientations around the vertical axis that were tested. Even if one takes into consideration the three outlier values the S/N values are consistently darker than the W/E values. It seems possible to produce quite different sets of values, and therefore draw different conclusions depending on how the instrument is orientated around the vertical axis.

  1. Future Planning.

I will repeat the test using all four possible 90° orientations around the vertical axis. On that occasion, it will hopefully have the time to take two or three sets of readings on the same evening and also to repeat all of them on two or more consecutive evenings.