brianvds


Brian's Notebook

Life, the universe and everything


Closing down
brianvds
I am moving to blogspot. This blog will remain online, but all new posts will be made to my new blog here:

http://brianvds.blogspot.com/

Why, you may ask? I just sort of like the look of blogspot more, and they have some neat features, e.g. I can upload images directly to the blog instead of first having to host them somewhere else.

So unless blogspot freezes up on me again (as it has done in the past, which is why I came to LiveJournal in the first place), my dubious creativity will henceforth be expressed on the new blog.

A DIY map of the moon
brianvds
I took this photo of the moon a few days ago, simply using the camera's 10x zoom to get a bit closer (click on the pictures to see larger versions in a new window):



I was looking towards the east, thus north was to my left, and therefore the moon's north is also to the left on the photo.

So let us rotate it a bit, in order to get north at the top, as we are used to in maps:



Of course, with astronomical objects it doesn't really matter much which way is up, and one can do whatever is convenient. Because many astronomical telescopes turn images upside down, it is not unusual to see maps of the moon with south at the top.

I have marked some of the major features of the moon:



When the moon is full or nearly full, as in the photo, most of the mountains and craters are difficult to see because the sun is illuminating them from above so they don't cast long shadows. Thus the moon is at its most spectacular when it is closer to half. On the full moon, however, one can clearly see all the lunar "seas" (so named by Galileo because he thought they might be oceans; they are in fact ancient lava flows.) The Latin word for sea is mare (pronounced "MAH-ray") and the plural is maria, and one often sees these terms used instead of "seas." Most of these are visible to the naked eye, and all can be seen easily with binoculars (with which one can also see quite a large number of the lunar craters, of which I only indicated two.)

Here is a list of the features I marked in the photo:

1. Mare Frigoris (Sea of Cold)
2. Mare Imbrium (Sea of Rains)
3. Mare Serenitatis (Sea of Serenity)
4. Mare Tranquillitatis (Sea of Tranquility) (This is where Neil and Buzz took their walk on the moon!)
5. Mare Crisium (Sea of Crises)
6. Mare Nectaris (Sea of Nectar)
7. Mare Foecunditatis (Sea of Fertility)
8. Mare Vaporum (Sea of Vapors)
9. Copernicus (crater)
10. Oceanus Procellarum (Ocean of Storms)
11. Mare Humorum (Sea of Moisture)
12. Mare Nubium (Sea of Clouds)
13. Tycho (crater)

Benoit Mandelbrot (1924 - 2010): Mathematics meets art
brianvds
I notice that the inventor/discoverer (take your pick) of fractal geometry, Benoit Mandelbrot, has died. Here is a short article from BBC about it.

Since the invention of perspective and the beginnings of modern anatomical studies in the Renaissance, there has always been a positive relationship between science and math on the one hand, and art on the other, even though they were at times barely on speaking terms. Mandelbrot was a major figure in this regard, although perhaps not intentionally. But I have always loved the imagery that can be created from the now famous Mandelbrot set:



I generated the above image (click on the image to view a larger version of it) with Fractal Explorer, which can be downloaded from the web for free, and can be used to create far more intricate and complex images than the above "quick sketch." Is it math or art or both? Either way, I think it is more beautiful than the work of many a famous abstract painter.

Of course, the noteworthy thing about fractals is that they resemble real things. Any artist who has ever painted something like this fern, or the lichens on the rocks behind it, has in fact indulged in the creation of fractal imagery:



It is also not difficult to see the resemblance between my fractal above, and these dendrite patterns in limestone (crystal dendrites look rather like plant fossils but are in fact just inorganic crystallization patterns):



We tend to associate the idea of geometry with the rather simple shapes that we all encountered in school mathematics classes. Benoit Mandelbrot was one of the first mathematicians to create, as it were, a mathematical description of far more complex shapes, including organic ones. His work also served as inspiration to artists, both traditional and modern.

Something Gothic
brianvds
A copy after "The Crucified Thief" by Robert Campin (c.1375 - 1444). For all its grim subject matter, the original is magnificent, a masterpiece of Early Netherlandish painting, and my rather crude copy cannot begin to do it justice. But here it is anyway; pencil on printer paper, 29cm x 21cm:


Highveld winter scenery
brianvds
A few days ago, some friends and I visited the small farm some 80 or 90 km east of Pretoria, where I spent much of my youth. I took some photos which, unless I messed up the HTML code or you are using some weird browser, should open in a new window when you click on the smaller images below.

There is a steep, rocky hill with a flat top that gradually slopes down into a valley towards the north. I took this picture on the hill, and its own south-facing slope (not visible here) is somewhat similar to those of the hills you can see in the distance. If you climb up those hills, you'll see that they too have fairly flat tops that gently slope down towards a further valley:



It is late winter, and the winter frosts seem to have killed everything. But this is normal for the highveld this time of year. For all the drought-stricken appearance, below ground the grasses are still alive and well and merely waiting for warmer weather and the first rains.

The soil is very rocky, and not exactly arable. But the grasses and wild herbs growing in between the rocks make for good grazing, and we saw several grey rhebok. Alas, with my simple point-and-shoot camera there was no question of taking photos of these small and rather elusive antelope.

The rocky habitat is a home to all manner of interesting things. This rock looks like someone has splashed paint over it:



It is in fact covered by lichens, which are a symbiosis of algae and fungi. Many species of lichens can live under rather extreme conditions. It hasn't rained here for many months, the nights are freezing, by day the rocks are baked in the sun. And yet they are a habitat to these hardy organisms.

This time of year many species of aloe are in bloom:



One can see more lichens on the rocks around it.

Here is a photo of the steep slope on the south side of the hill:



The tangled, dry shrub in the left foreground is wild apricot. It looks as dead as everything else, but it will soon turn green and by January or February will bear delicious, sweet-sour fruits that superficially look a bit like apricots, hence the name.

Most of the green trees down in the valley are, alas, invasive eucalyptus and wattle trees. Native to Australia, they are attractive trees but here in South Africa have become quite incredibly noxious and virtually indestructible weeds. They form a habitat for, well, just about nothing. Their leaves are not particularly edible (though I have on occasion seen cattle browse them a bit). They do not bear fruit, or serve as hosts for insects, that are of any use to local species of birds or mammals. And almost nothing will grow under them. Large swathes of the highveld are sinking below an ocean of these trees.

I have tried cutting them; they simply grew back. I sawed them off and poisoned the stumps; within a year they had all sprouted again, and for every trunk you cut off, five new ones grow in its place. It is an ongoing battle.

In their native Australia they have all manner of competitors and parasites that keep them under control, and one really needs to import some of those to do the same job here. But importing foreign species is a risky business - you need but to look at the eucalyptus trees themselves to see how easily it can end in disaster. They are also of some economic importance because the wood is extensively used in the construction and mining industries. In Mpumalanga province there are large plantations of these trees. There are thus established economic interests involved, and many powerful people who would not be too amused at the thought of seeing their profits disappear down the throat of some Australian parasite.

And thus the highveld ecosystem, already under severe pressure from farming and urbanization, is sacrificed to economic interests. It might not be the most obviously spectacular or glamourous habitat on the planet. But at least to me, it is possessed of a subtle beauty that grows on you the more you see of it.

A creek flows in the valley, into this small, shallow dam:



In dry years the creek sometimes goes completely dry, and most of the dam as well. But we had good rains last summer, and there is still plenty of water, even after many months without any rain.

I can also mess up Michelangelo...
brianvds
Not content to make a mockery of Bouguereau's refined figurative art, I decided to turn my infernal gaze on Michelangelo's Sistine Chapel decorations. Some friends and I regularly do "hobby evenings": we sit around a table and get drunk, and everyone works on a hobby, whether it be scrapbooking, drawing or just drinking and talking nonsense. This rough copy after one of Michelangelo's figures was the result of one such evening:



Now that I have given up trying to copy anything correctly, or achieving any illusion of realism, I am having far more fun with the whole thing. Alas, it does cut a gruesome swathe through the works of the great masters of old...

Apologies to Mr. Bouguereau...
brianvds
...for this rather amateurish copy of his masterpiece "The Bather." I have gone and turned it into a piece of awkward post-impressionism. The deep rumbling sound you hear is the master spinning in his grave. Alas, strictly realistic drawing is not my strong point.

Mechanical pencil, HB, on a scrap of printer paper about 15cm x 20cm:


Enduring duress due to Dürer
brianvds
Another of my rather small (about 10cm x 15cm) ballpoint sketches after the Old Masters; this time an engraved portrait by Albrecht Dürer of his friend Willibald Pirckheimer.



Alas, "drawing like Dürer" is something far easier said than done! Still, I suppose one has to try.

Small copies of great works
brianvds
In some quiet moments at work, I made time to make sketches after some master artists in a small (about 10cm x 15cm) sketchbook. As usual, I couldn't really do justice to the masters, but I suppose one has to start somewhere. They are all in ballpoint pen, and as I usually do, I lived dangerously by not first making pencil sketches - just went at it with the ballpoint and hoped not to make too many mistakes!

Here's one copied from a character in the Tintin comic book "Flight 714"; a greedy, self-centered industrialist named Laszlo Carreidas, and one of the most hilariously unpleasant characters Hergé ever created:



After a painting by Filippino Lippi (c. 1457 – 1504):



And after an artist I recently discovered, namely the Victorian painter Evelyn Pickering de Morgan (1855 – 1919); I like her somewhat pre-Raphaelite fantasies:


An unexpected visitor
brianvds
This magnificent fellow with the red, glowing eyes and ominous skull design on its thorax fluttered into the kitchen last night. I caught it before the cat did, and put it down on a piece of paper where it politely sat still for a few photos, and remained still even when I put down a matchbox beside it for comparison. I then took it outside where it flew off into the night.



Another view of the moth. Unfortunately the bright white paper caused the critter itself to be a bit underexposed, but it was very darkly coloured, so the photo is not too inaccurate a representation.



Update: I have since managed to identify it; as I thought, it is a species of Death's Head hawk moth, more specifically, Acherontia atropos:

http://en.wikipedia.org/wiki/Death%27s_head_hawk_moth

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