Atmospheric optics picture of the day

I posted about the wonderful solar halo display over Porto last autumn. Of course I sent my photos to atoptics and got an excited response that I may have captured a rather rare display. After much analysis of my large set of photos the good news is that indeed I was lucky enough to see a full display of Lowitz arcs. The pictures and description are up online at atoptics now as the picture of the day.

Year on year

My Mathematica programs are biting back today and undocumented interpolationpoints commands are laughing at me every time I turn away. Still, answers are converging in hoped for directions and all should be well soon.

Anyway, I haven't had a chance to write up much more about my trip to Porto, but I will put up a couple more photos from this splendid city.

On the Sunday as I walked around the city with some friends from Couchsurfing, and waited for my midnight bus, I had a chance to go to a few wonderful viewing areas to see the city as the sun was setting. In particular the rather charming Crystal Palace gardens (no longer with a Crystal Palace, but a somewhat less attractive auditorium) gives a great view over the river, with the Port Cellars peppering the opposite bank:

Further along the coast the scenery changes considerably and you get a real view of the ocean and the smell of the sea replaces the smell of ancient city life:

A few more photos to process at some point too, but they will have to wait.

Anyway, everything is busy as ever at the moment, with a short trip to Dublin to give a seminar in a couple of weeks, and a semi-public lecture on atmospheric optics to give at the beginning of December. I'll be heading to Madrid to give a talk at the Christmas meeting too, before heading back home for a few days over Christmas and the new year.

Today we had a fascinating talk on the use of Turing machines to study evolution and I spent lunch quizzing the speaker on many things which have been on my mind since the amazing talks by James Glazier on morphogenisis back in 2007 in Beijing.

On a side note, I've now been living outside China for almost exactly a year. I never imagined how much I would miss the place, and although I'm extremely happy here in Spain, in the department, in the city and in my current position, there is something unreplacable about life in that sprawling, dirty, glorious city of fourteen million, which is at the same time undescribable and unforgettable. I was hugely lucky to have the chance I had in China, and am equally lucky now to be here in Santiago, in a very different, but equally stimulating environment.

Anyway, Mathematica seems to be giving me better answers now, so I should get back to it...

Porto in brief part I

Written Monday evening...

I arrived back from Porto at around 5.30 this morning after a three hour bus ride having failed to secure a ticket in time for the afternoon bus. I had to be in Santiago today to get a few admin tasks tended too, and consequently I'm feeling pretty tired.

However, Porto was truly wonderful. I spent Friday in the university and gave a talk in the afternoon, which was very enjoyable, even if the bulk of it was aimed at a minority of the audience. It's tough to give a specific research talk to a group who knows little about the generalities of your subject, so I gave a half hour introduction and then a half hour on the details of my last paper. After this I spent some time discussing with one of the researchers there about his recent work, and some possible extensions which I hope we will explore via email over the next few weeks.

I left the department in the evening and walked over to the Casa da Musica, a striking contemporary building, to meet my couchsurfing host. We met up and did a little shopping in preparation for an evening feast with around ten of us. I was exceedingly lucky with my host, who was not only a lot of fun, and a very generous human being, but she happens to have a degree in the science of wine and winemaking and works at one of the major Port makers in the city as a tour guide when she isn't making her own wine in her family's estate.

This meant that the weekend was a luxurious treat of learning and tasting some of the best wines of the region (produced in the Douro valley), as well as having a private tour of the port cellars and a tasting of a huge range of very very fine beverages.

In terms of gastronomy, Portugal never suffers from any subtlety in its foodstuffs, and on Saturday as I walked around in the town centre, I spotted a cafe offering Francesinhas. I'd heard of these but wasn't yet aware of what they were. Never, to be scared by the unknown I ordered one (the waiter asked me if I just wanted one, to which I nodded, not knowing whether this would be enough). This must truly be the king of high calorie lunches, designed for a hard days labour. A Francesinha, ironically given the title 'little French girl' is prepared by taking: steak, minced pork, fried egg, sausages, sliced ham and thick slices of cheese, and putting the whole thing between two or more slices of bread. You then take this and drown it in cheese, so the whole thing is covered and you have to dig to discover that this is a carnivores delight. Take your meat-drowning-in-cheese-feast and pour a thick and spicy tomato sauce over the top.

My guess is that this beast has around a 3000 calorie kick to it. Just in case you're not satisfied, it comes automatically with a plate of chips. Apparently by ordering it with a glass of water and not beer I may have caused some sort of gastronomic offense to the owners of the establishment!

Anyway, I finished my lunch, worrying slightly about heart palpitations and spent the next hour or so wondering the streets. Later I met up with a friend of my couchsurfing host and he took me on a tour of the city, describing much of the history and how it had evolved over the last few hundred years. His time studying architecture made this a fascinating insight into the city. During this time we went up the steeple of one of the old churches to get this wonderful view of the city (click for a huge version!):

We then headed over to the other side of the river to spend a glorious afternoon Port wine tasting with my host, trying everything from dry white ports, great with tonic, to 30 year old tawnys and a deep rubys.

The evening was spent at a chef's house, eating vegetarian cuisine which made me feel only slightly less guilty about the herd of animals which had been slaughtered for my lunch. The chef was also a tour guide for the Port cellars and so a fine selection followed the meal....do I see a theme emerging from this weekend?!

To be continued...

Stunning solar halo over Porto

From ice and sunlight amazing things will come...

I'm going to do a full Porto blogpost soon, but I needed to get this out before anything else, as anyone who knows me will understand.

Sunday afternoon I was in the gardens of a wonderful modern art museum in Porto (Serralves), walking around and taking in the sun with a friend of my couchsurfing host.I looked up, as I seem to spend most of my time doing and caught a glimpse of a solar halo beginning to form. We got out into an open area and watched as the upper arc of the solar halo turned into the most stunning display I've ever seen.

As the field of ice in the clouds swept across the sun, for around half an hour the sky was illuminated with the most stunning arcs, halos, sundogs and perhelia I could imagine. Of course I got a ridiculous number of photos of this and have only gone through some of them in detail. In particular it appears that the pictures of the sundog may have captured a phenomenon rarely captured on film. As explained to me by the author of the superb site atoptics when I sent him the photos:

'...But something about your image caught my eye. I then severely enhanced it and have attached the result. It looks to me as though you have the very rare Lowitz arcs and have unusually captured the upper, lower and middle Lowitz components. See the very first Lowitz image for comparison..' This effect was first captured here, but it seems possible that I may have caught it too.

On top of the 22 degree halo, the upper tangent arc and the sundog, there was a lovely 120 degree parhelion, something I'd never seen before. Having spent some time reading atoptics in the past I had a good idea where each of these effects was coming from and to see them so vividly was wonderful! Each part of the pattern comes from a particular shape of ice crystal with a given orientation and a specific path of light, sometimes through the faces and sometimes through the edges.

Of course I told those around me about the amazing display in the sky but all but two of them showed no interest at all, looking up and then seeming rather surprised that I'd bothered them about it.

Anyway, here are a few of the pictures I took of this startling sight:

The upper tangent arc, the 22 degree halo and the sundog:

The halo, the sundog and the parhelic circle:

The sundog, the parhelic circle and the 120 degree parhelion:

and the 120 degree parhelion shining brightly. It seems that as noted occasionally before, this has a faint redish tinge to it (only seen on the zooms):

All of the above images can be seen in larger sizes by clicking. There are also currently a great number more photos on my flickr account as I've simply dumped them up there for now for further analysis.

I have mixed emotions about this. On the one hand I was overwhelmed with the sight, grinning and running around like a kid in a sweet shop for half an hour, while on the other I'm saddened by the lack of interest most people have in the wonders of nature. Still, in a few weeks I will be doing my bit by giving a lecture to the whole physics department on atmospheric optics. I hope to get another few people enthused by what is out there!