Equilux

Though it's a seldom used term, I thought I'd write something about it since today happens to be the equilux. No, I hadn't heard of it either, but I was reading wikipedia and was perhaps a little too interested by it.

A similar, more commonly used term would be the equinox, which comes from the latin "aequus nox", meaning equal night. It's a little bit of a misnomer, since the it doesn't necessarily fall on the day which is the same length as the night. The equinox isn't really a day at all- it's simply the moment at which the sun crosses the equator. This Spring, that happens to be at 5:12am on Tuesday (20/3/12). That day where I am in Fife, Scotland happens to last 12 hours and 13 minutes.

The equilux is simply the day which lasts closest to 12 hours, which would make it today, as it lasts 11 hours 59 minutes.

This necessarily true of everywhere, however. It's certainly not true of anywhere in the southern hemisphere. I can only say with certainty that it's true for Scotland, and probably the rest of the UK. Sydney, Australia for example will have an Equilux on the 24th March, with the sunrise at 7:02am and sunset at 7:02pm.

Since the moment of equinox is the when the sun crosses the equator, it is not dependant on the observers location so it will be the same time worldwide. The only possible difference in this will be down to time zones, or the fact that my 2 sources stste different times! Wolfram states 5:12am, but Wikipedia and it's source state 5:14am. Go figure.

The reason that equilux and equinox are different is mainly because the sun is so big and so close. If all that light were to come from something that appeared in our sky as small as any other star, it would rise and set in an instant. It's the time that it takes such an apparently large disc of light to set that adds these extra few minutes onto the day closest to the equinox.

Had I simply read, understood and moved on, I guess that'd be the end of my blog post, but no. I went on thinking about it and for some reason or other I decided to challenge myself to figure out the subsolar point at equinox. That's where exactly on earth would see the sun as directly overhead at the time of equinox.

Possible places are immediately rounded down of course, since I'm giving myself the latitude for free. Since equinox is the moment the sun crosses the equator, the latitude of the subsolar point would have to be 0. 

Since the sun will be overhead this point at midday (by conventional solar time), it shouldn't be too difficult to make this calculation. The time given for equinox is 5:12am, so this place is 6 hours and 48 minutes ahead in time from 0 longitude (Greenwich meridian, therefore GMT). For calculation, put into the decimal 6.8 hours. (48/60 = 0.8)

Another known fact is that it takes 24 hours for the earth to rotate 360 degrees. So I can use this to work out the longitude, which will be the angle the earth will rotate in 6.8 hours.

Rotation (r) / Time taken (t) = constant

r1/t1 = r2/t2

r2 = r1/t1 * t2

( 360 / 24 ) x 6.8 = 102 degrees.

Going with the 

So the subsolar point at equinox is 102 degrees different longitude than Greenwich. This makes some countryside in Pangkalan Kuras, Indonesia the exact point I was looking for. I'm just amazed I hit land!

If you were thinking that the 2 minute difference between sources might have made a difference, I've checked that out too. The 2 minutes equate to 0.5 degrees of rotation, which in turn equates to about 35 miles west of the last link.

Keyboard Shortcut of the day: Ctrl-W

I've found another one!

It's Ctrl-W and it closes the current tab.

Since I found it's come in useful when I realize I have 40 tabs open at once and should probably get rid of some. Using it in combo with Ctrl-tab, makes for a pretty speedy way to cut off pointless tangents.

I guess I'll keep posting these every Fridays until such time as any of the following happen:

1. I don't discover any more that I deem to be worth mentioning as an individual post and resort to posting the list of all of the shortcuts I can think of (already written as a draft post)
2. I post one of these and it gets zero hits. Literally none. Even my least read page ever got 10 hits.
3. I forget about the blog entirely and just don't post anything for months.

Shit Ticketmaster says

Most Human decisions are based on patterns, and this is something that a lot of the digital world seems to have cottoned on to. My TiVo box 'thought' I might like to watch Sunshine because I recorded 127 hours, that I might like Futurama because I gave The Simpsons a thumbs up and Last.fm suggested that I listen to Eagleowl because I've listened to Meursault and King Creosote.

They do this by making a database of all information on any film, tv show or music track with as much relevant information as possible. Then whatever I've watched or listened to is compared to other entries in the database and those which have matches are returned.

127 Hours was directed by Danny Boyle, so when another of his films, Sunshine came on TV a few weeks later, it was flagged up to me. Likewise, The Simpsons and Futurama are both created by Matt Groening, and Eagleowl, Meursault and King Creosote are all Scottish artists tagged as similar genres and have shared members and played in similar venues. It's also very possible that these suggestions were based on the habits of other users.

These suggestions and the methods for generating them are becoming pretty commonplace but one place that still doesn't seem to have bothered is Ticketmaster. As I'm sure their terms and conditions say, they have access to my entire order history. On inspection, they'd find that I've bought dozens of tickets, dating back as far as about 2006. I've since bought tickets to T in the Park,  several Fringe shows, Radiohead, Biffy Clyro, Death Cab For Cutie, Red Hot Chili Peppers, Frightened Rabbit, The Twilight Sad, Admiral Fallow, Ross Noble, Stereophonics... and so on. The vast majority of these shows have been in either Edinburgh or Glasgow.

With this information, it ought to be pretty simple for them to get a general idea of what I like to go to, where I like to go to, or otherwise pigeon-hole my habits so that they could somehow use it to target the advertising that they send me.

Instead they send dreadful weekly emails which have no bearing on any of my past purchases. One of the worst examples I remember was headlined "Don't miss Take That" when the closest show mentioned was in Birmingham, over 300 miles away. The whole point of sending out emails in the first place would be to rouse interest in anything they had to offer, but instead it just leads me ignoring the emails, and once they started piling up, I would unsubscribe. Now, even if there were anything I were interested in paying for, they have lost their chance to sell it to me. When will they learn?

Apart from this, the ticket site (and it's definitely not just Ticketmaster) ought to realize that they just aren't likely to be the place where I'd first hear about an event. It's far more likely that I would subscribe directly to  newsletters, tweets or facebook posts directly from an artist in hope of hearing about any upcoming gigs from a less crap-polluted source.

I guess it's not really a problem because as I've pointed out, I chose to subscribe in the first place, but I still manage to get wound up knowing that there is crap floating around the internet.