Laser Safety

When green lasers first made their appearance amateur astronomers who regularly gave presentations where they had to point out objects in the sky, breathed a collective sigh of relief.  No more trying in vain to get viewers to see what it is you are referring to.  Most of us remember the dialogues that went something like this.

“Which star?”
“That one there.”
“The one on the left or the one below?”
“On the left, below? But there’s only one bright star there.”
“No there isn’t, there are three.”
“Okay! Lets start over.  Do you see the top of that tree.”
“Good! Now go straight up from there for two hand breadths. Do you see that very bright star?”
That’s the one I was referring to.”
“That one!  No I was looking at those three over there.”
 At which point the viewer turns almost 90 degrees and points at some totally unrelated patch of sky.

Then came the green laser and all, well almost all, confusion was banished from star shows.  But now it seems that all sorts of people suddenly have green lasers. Suddenly it has become fashionable to shine these lasers at aircraft coming in to land or into the eyes of motorists on the freeway.  Then there are those who use them to disorientate police and other law enforcement personnel when they are trying to round up lawbreakers.  The result is that amateur astronomers are going to come second because already authorities in some parts of the world have started banning the use of green lasers. This has already happened in a number of areas. (In New South Wales, you can be fined for possessing a laser pointer, and you can go to jail for up to 14 years for a laser assault.) There are also strong calls in Canada, the U.S., and the U.K. to restrict or ban lasers.

The Bloemfontein Center of the Astronomical Society of Southern Africa has posted an interesting video about laser abuse and the Pretoria Center has a comprehensive document covering laser safety on their site as well.

An ELF Astronomy special offer in October 2013

You snoozed you lost!  Sorry folks but the booking for these special offers has closed.  See you all next time.

Stargazing and hiking weekend at Bergwater Lodge on the farm Pietersfontein in the Montagu district.

Bergwater Lodge is set in magnificent surroundings
The view of the Pietersfontein Dam from Bergwater Lodge.

Book in Friday 18 October from 14:00 and depart on Sunday 20 October by 12:00

Accommodation consists of
Eight rooms with a double bed and two single beds and one room with only a double bed.  All bedding and towels are supplied.
R1500 for per person sharing
R1700 for single accommodation (not sharing)

Above mentioned prices include the following
A welcoming sherry, sovaldi tea or coffee
Build starwheels for use later in the evening
Supper (Friday evening at 18:00)
Stargazing – provided the weather permits it! In In the advent of inclement weather we will offer                         a substitute activity of an astronomical nature
Late night tea/coffee
Breakfast (Saturday morning from 08:30 to 09:00)
Hiking and a walk to the dam
Lunch (Saturday at 12:30)
Build starwheels / look at the sun through a telescope
Astronomy presentation
Supper (Saturday evening at 18:00)
Stargazing – provided the weather permits it!
Late night tea/coffee
Breakfast (Sunday morning from 08:30 to 09:30)
Depart by 12:00

Please note that this is a self-drive weekend.  We will provide the maps and detailed instructions on how to get to Bergwater Lodge, but everyone has to drive there in their own transport.  The distance from Cape Town is about 180 km and the last 10 kms are on a gravel road.  There is no mobile reception at Bergwater Lodge.  A land line is available in case of emergencies.

What you must provide
Any special or extra snacks and refreshments
Water bottle, sunscreen lotion, hat
Insect repellents
Warm clothes – it will probably be hot during the day but it can still become quite chilly at night
All medication, especially any prescribed medication

Bookings must be made as soon as possible and no bookings will be accepted after the 20th of September 2013.
Please provide us with proof of payment before 20 September 2013 to secure your booking.
If you cancel before 30 September 2013 we will refund 80% of your payment. If you cancel after 30 September no refund will be made.

Contact Edward Foster at 083 787 0792, or Lynnette at 084 512 9866. Our
landline is 021 982 6496 or email us at

Small Business Expo

Small Business Expo: Bellville Public Library, September 2013

Day one – Tuesday 10 September

The object of the exercise was to do some advertising for ELF Astronomy.  It was all a bit of a rush because on the one hand we were tying the last loose ends of the National Science Week report and at the same time there was the grant proposals for the IAU.  Sorry I forgot about the grant application for the National Space Week, which we are trying to tie in with the Under One Moon event and we are planning a two day visit to the Bonnieval Bonanza.  in between all this Lynnette is trying to keep the administration of the Spring Southern Star Party up to date.  On top of all this both Lynnette and I have had a serious case of the coughs and sniffles and Auke has also been a bit under the weather.

For the Expo Auke designed the most magnificent A1-poster for ELF Astronomy on a moon background using some of the high resolution visuals Clementine produced. A smaller A3-poster with a night image from a previous Star Party is also stunning.

The first day was fairly quite with one or two very interested persons and a page full of names who want to be kept updated about future developments.  We will of course oblige them.  Thursday is the big day and according to Jackie Terblanche Saturday we can expect quite a lot of traffic.

The stand and me trying to convince the laptop to talk to the second screen. Why my bald patch had to feature so prominently I’ll never know.
Our stand is right across from the Library Security Staff, Zinnia and Pikkie, who are always ready to lend a hand.
Auke’s magnificent A1-poster. By the way, there are four of the Apollo landing sites on here as well as two of the Soviet Luna landing sites.

Day two – Wednesday 11 September

Quite a bit quieter than Day 1.  I had the camera set up and taking shots every three minutes from behind or tables in the stand.  Here is a selection of those photos

Our first two customers of Day Two. Interested but not enough to go on a tour or come to Star Party.
I don’t think tackling them and sitting on them until they sign up is going to work.
Pikkie, the security man checking up on one of our customers. Well, almost a customer, but let’s call him an interested person, if you want to be finicky about terminology.
My explanation is obviously not meeting the standards of a skeptical interested person.
I might just be getting through to him, he’s unfolded his arms. I soldier on while Lynnette adds a name to our growing list of interested persons.
It turns out that this gentleman was in the wrong building for a meeting and was just leaving, when he spotted us. He is very enthusiastic about astronomy and we will very possibly see him at the next Star Party.
A very serious young man in consultation with Lynnette
Lynnette explains something to a very knowledgeable you man from North Pine Technical High School
How does the Universe expand? You get hold of the two edges and pull, very hard.
The young man speaking to Lynnette is also from North Pine Technical High School and he showed a great deal of interest.
The young man in the yellow sweater is a statistics student and he says that their lecturer gives them astronomy data to practice their stats on?
At this point I am deep into dark matter, dark energy & black holes which, as you are all aware, I know very little about.

Day three – Thursday 12 September

On an outing like this you spend a lot of time standing around and when you’re tired of that you stand around and then you walk around and then you start the cycle again.  In between somebody who is interested stops by and you pounce and talk a bit before starting the cycle again. Jokes aside it really isn’t that bad and we are slowly but surely building up a nice list of contacts.

This gentleman did not want to be spoken to, he just wanted to read. He stood like this for around ten minutes reading the text on three A3-posters. That’s about 100 words. Obviously a thorough reader.
Jackie Terblanche, from the Reference Section of the library, who organized the Small Business Expo for the Bellville City Library.
Christelle Lubbe the head librarian. “The loo’s over there”, or perhaps “get out, and I mean now”. Maybe it was something a tad more imperialistic like “Your hinterland lies there.”
I have always maintained that the back is the best part of a donkey.
This enterprising lady was all fired up to go to the SSP and said she loved camping, Then it turned out that she want to hitch a lift for herself, her tent and her supplies for the weekend. When we indicated that we doubted if shed find what she wanted easily, she seemed to lose interest in the SSP. Can’t for the life of me think why though.
The young man in the picture (no not me, the other one) is from the Congo-Brazzaville, He wasn’t interested in our tours but was all fired up to do a tourism diploma and a guiding course.
The lady on the left expressed the opinion that one day we would all realize that God was so all powerful that he could make rocks look as if they were two million years old just to fool us. Okay and she also happens to be a teacher.
This lady was somewhat skeptical about the ages of fossils but as she was in a hurry we did not get to discuss her opinions. She promised to come back on Saturday – watch this space.
Lynnette and I are letting our hair down. Actually it works wonders keeping ones ears warm too and with the dark glasses, who knows what possibilities there are out on the streets.

Day four – Friday 13 September

We were a bit late, much to Pikkie, the security man’s amusement, because I had told him I would be there before him.  Definitely our slowest day and boredom has really begun to set in. I hope tomorrow is a bit livelier. Lynnette even nodded of once or twice and I had to give her gentle nudges to bring her back to the present.  We saw Carol and Miere leaving just as we pulled in, but all our efforts to attract their attention were in vain.  We left early at 15:15 and went home to get some stuff we wanted to drop of with Sunelle at the Brackenfell Public Library.  Snorre, our cat went with us on his leash and caused quite a stir at the Library.  Sunelle was quite happy to put up some adverts for the upcoming SSP and also for the two tours in October.

These young ladies did not want to tour but they wanted to know a lot of other things. Here we are sorting out the phases of the Moon.
These young ladies did not want to tour but they wanted to know a lot of other things. Still on the Moon but now it was the Moon’s topography.
These young ladies did not want to tour but they wanted to know a lot of other things. Now we were on fossils, the West Coast Fossil Park, the Frazerburg Palaeosurface and of course evolution.
These young ladies did not want to tour but they wanted to know a lot of other things. by this time we’d moved on to Blombos, Border cave, Florisbad, “mrs” Ples, Sterkfontein and origins of Man. The key question was whether I thought I was related to a Chimpanzee!

Day five – Saturday 14 September

A very slow morning indeed.  The consensus in the library was that two factors were probably to blame.  Firstly South Africa was playing rugby against New Zeeland and secondly it was raining .  The lady who promised to come back and discuss fossils with me did not put in an appearance either. After fighting boredom until just after lunch we decided to pack up and go home.

What did we learn during the course of the week?  The general public is not well informed about astronomy or geology, but that we probably already knew.  The general South African public is extremely reluctant to spend money on any form of touring in their own country and they are also not convinced that being driven and having a guide has any advantages.  But the five days had the advantage that our database of names and contacts has increased substantially   I suppose it is now up to us to make the best use of the additional names.

Two tests of your instinctive perception of things

During National Science Week, 2013, AukeSlotegraaf made two posters which illustrated the following two problems.  The important thing is to first give your own gut-feel guesstimates of the answers, before you set about doing any calculations.  Here are the problems, but remember, guess first, calculate later and surprise yourself with how wrong you can be.  I was way, way out and almost everyone else I know was to.

Problem One

Imagine that you can take a piece of rope and stretch it tightly all the way around the earth at the equator.  Let’s assume, for ease of calculation, that the Earth’s circumference is exactly 40 000 km (or 40 000 000 m) then the piece of rope will also be 40 000 000 m long.  The next step is that you have to organize an army of underlings to station themselves all along your rope at 2 m intervals.  Now I know that in practice this won’t quite work, but just assume it is possible and get them all in position.  Now cut the rope and insert a piece exactly one metre long so that your rope is now 40 000 001 m long and it will be slightly slack because of the insertion.

The next step is to get your multitude of assistants to lift the rope so that it is once again tight and forms a perfect circle.  All got the picture?  Good!

Now the question is how high above the surface of the Earth is your circle of rope going to be? Remember to guess first before doing the calculation.

The answer to problem one

Your imaginary rope will be just a tad under 16 cm above the surface of the Earth after you’ve added in your one meter of rope.  What was your guess before you worked it out?

Problem Two

Assume you have a very large piece of standard 80 g/m² paper which is 25,4 µm or 0,0254 mm thick .  Now fold it once.  You now have two thicknesses of paper or, put differently, you have double the thickness of paper you started out with.  Now fold it again.  You now have four times the thickness of paper you started out with.  Fold it a third time and you have eight times the thickness of paper you started with.  A fourth fold will give you 16 times the thickness you started with and so forth.

Let’s assume your piece of paper is so large, and that you have the space to maneuver the paper around in and to keep folding it.  How many times will you have to fold it before your pile of folded paper’s thickness equals the average distance between the Earth and the Moon, ie. 381 550 km?

Once again, please remember to guess first before you calculate.

The answer to problem two

You have to fold 42 times.  Actually 41 takes you to a point just short of the Moon and at 42 you overshoot slightly.  This is the same sort of problem as the guy who put one grain of rice on the first square of a chessboard, two on the second, four on the third, eight on the fourth and so on. Remember there wasn’t enough rice in the country to fill up all the squares on the chessboard.

1st Durbanville Scouts – Friday the 23rd of August

Part of our e-mail advertising campaign for National Science Week 2013 (NSW) was to send e-mails to all the Scout Troops and Voortrekker Commandos in the vicinity of the venues for our NSW presentations.  One of these was the 1st Durbanville Scouts and they were also one of the few to reply as well.  The Scoutmaster, Nick Pieterse, wanted to bring a group of 40 of his scouts round to Willowbridge Life Style Shopping Center.  Great stuff, except that we were worried that we would not be able to pay enough attention to them if we had the expected high number of the public also wanting to look through the telescopes.  So we suggested that he should consider a later date when we could go to the 1st Durbanville Scouts and do a presentation at there headquarters.  They agreed and a programme was arranged which would, among other things, specifically address the requirements for obtaining an astronomy interest badge.

The requirements for the interest badge would also require doing practical observations so we decided to cover the ones requiring only theory on the first visit and to them arrange second visit for the more practical ones . The interest badge, I must add here, is not all that basic and not all that simple either. Part of the first evening would be for the Scouts to build a Southern Star Wheel as we felt that once the scouts had that and could use it, they could also tackle some of the practical issues more easily. I would give a short talk about the Solar System in which I would cover as many of the theoretical requirements for the interest badge as possible.  Auke e-mailed the pdf’s of the Southern Star Wheel to Nick so he could have the appropriate number of copies made for the evenings activities.

We arrived on time and after the Scouts had performed their opening ceremony, Nick introduced, Auke, Lynnette and myself and we set up a makeshift projection screen and I got the laptop and projector organized. In the meantime the Sar Wheels were handed out, glue and incisors were organized and Auke explained how to cut out and assemble the Star Wheel. While doing this he also gave them a problem to solve.

The pre-assembly cutting is well underway under the watchful eyes of Nick and Auke (black beanie).
Some just cut while others apparently gave the matter some thought before proceeding
Seniority seems to have its perks when it comes to sitting on the floor or on a bench
Auke gathering photographic evidence while Edward and Nick keep their hands warm

After lots of cutting and gluing, plenty of sticky fingers and a mistake or two the Star Wheels were done and could be demonstrated.  Most caught on very quickly and a quick explanation helped those that didn’t to get the hang of things.

Auke cracking a joke while explaining how the Star Wheel works
Edward clarifying a minor uncertainty
Edward in last minute consultations as Nick , in the background starts the ball rolling to pack up and go home.

After everybody settled down I gave my talk and answered a few questions.  I gave the group a guideline on how to visualize the scale of the Solar System and also left them with a problem to solve.

I have e-mailed a copy of my talk to Nick and he can distribute it the the Scouts if required and I will also a set of answers and background material for the interest badge.

We are hoping to arrange the second visit for the practical session and some telescope work as soon as it looks as if the inclement Capewinter weather is going to give us a break.

Deep Sky Weekend at Night Sky Caravan Park, Oudekraal, Bonnievale: 08th to 11th of August 2013

Deep Sky Weekend at Night Sky Caravan Park, Oudekraal, Bonnievale:  08th to 11th of August 2013

Lynnette and I left home with Snorre, our cat, in the Vito on the 7th hoping to get in a day’s rest at NightSky after the hectic 9-day marathon of National Science Week that ended on the 4th of August. It was cold and rainy all the way and we were both holding thumbs that the weather people were right and that it would clear up by the Friday.  We stopped off at the Pitkos Padstal on the R60 where Francis had delicious freshly brewed coffee and hot roosterkoek with melted cheese and biltong.  Snorre gave his purring stamp of approval to the food and we bought several bottles of the Nuy Red Muscadel to ward of the cold we knew would be waiting at NightSky.


NightSky Caravan Park is a scenic venue even if it is cloudy or if it rains and it has this stunningly photogenic willow tree.
Fairly heavy snow on the higher peaks of the Riviersonderend Mountains
Snow on the distant peaks of the Langeberg Mountains reflecting the afternoon sunlight

At NightSky everything was very thoroughly wet and we wondered if there was anywhere dry enough for Iain to pitch a tent.  I was still wearing the brace after my lumber fusion in May, so unloading was slower than usual, but as soon as it was done we got the fireplace going and before long the house had warmed up nicely. Then Alan and Rose arrived and eventually found a spot to park their caravan.  There were intermittent showers all afternoon and well into the night, but by morning only the clouds along the Riviersonderend and Langeberg mountains remained.  As they cleared away we could see that the higher peaks were all covered in snow, which explained the sharp nip in the air.

The important thing though was that we had almost clear skies and it looked as if they would clear completely by evening.  During the course of the day Auke, Wim, Malcolm & Elize, John, Brett, Leslie and Kechil and her group trickled in, as well as Ludwig Churr and Sandy Struckmeyer.  Wim as well as Malcolm & Elize unpacked and then headed off to McGregor to see if they could get any closer to the snow, but to no avail.  Anyway, by sunset everyone was back and set up to start observing.  Alan was determined to push up his tally of Deep Sky objects, Leslie and Brett had all their astrophotography paraphernalia set up and the rest of us each had our own little niche from which we could contemplate the near perfect dark skies above us.  In between we wondered around exchanging views and opinions with whoever you stumbled across in the dark.  The only people that were not difficult to find were Brett and Leslie, because their outfits were lit up like Christmas trees.

Brett in the centre of the photo and Leslie on the right were easy to find in the dark. Alan’s telescope on the far left, and his caravan are reflecting the light form the other two
Leslie headed East leaving a fiery trail

Saturday was a beautiful day and Wim went off in his pickup to explore farther afield.  Leslie and Brett went to Bonnievale to find hot water bottles which they intended using to ward of the cold during their nocturnal activities.  They both claimed that this worked well except for the slight scorching they experienced after filling them with boiling water as the bottles had no covers.  Saturday night was not quite as clear as Friday night and on both nights dew was a problem, especially in the areas closer to the dam.  Alan, I know, had two very successful nights of observing and has increased his tally of Deep Sky objects considerably.  I spent quite a lot of time getting used to my new Nikon D5100 and got some fairly good shots of the area around Crux and the Scorpio/Sagittarius section of the Milky Way while Lynnette spent time hunting globulars.  In general we all had two quite cold, definitely sleepless, but astronomically speaking quite productive nights.

Auke explaining to Lynnette and pointing out things with a laser. All the action is reflected on the back of the Vito on the left of the photograph


On Sunday everyone packed up, goodbyes were said and another successful DarkSky gathering came to an end.  As we were packing up I noticed that Snorre was limping and inspection of the left front leg turned up a puncture mark high on the leg.  I thought this was a bite from one of the feral cats that prowled the area and we decided to head for Bergwater and spend the night with Christine so that we could take him to Marina, the vet in Montagu, early on Monday morning.  From past experience I knew just how septic these bites could become and I did not want that to happen to Snorre.

Snorre the MCWC (Main Cat What Counts)

At Bergwater Christine was her normal cheerful self and the three of us, plus a rather subdued Snorre, spent the evening around a large fire talking and enjoying Lynnette’s excellent curry and rice until the wood ran out.  On Monday morning Marina confirmed that Snorre was running a fever and prescribed antibiotics.  On the way back to Brackenfell we stopped off at Pitkos for more of the usual before tackling the last lap.  The stops at Pitkos on both legs of the journey were actually not just for the coffee and roosterkoek, although that would have been a sufficient reason, but also because my back could not yet handle long periods of sitting in the vehicle.  Suitably fortified we set off home and, instead of using the Huguenot Tunnel, we went over Du Toitskloof Pass, but the normally fantastic view from the summit was unfortunately spoiled by low clouds.  Once home there was all the usual unpacking before we could settle in and get a good night’s rest.