Friday, 6 March 2015

my sixth planet

I’ve seen all the naked eye planets: Mercury, Venus, Mars, Jupiter, and Saturn.  In fact, Venus, Mars and Jupiter have all been readily visible the last few nights.

But tonight was a first: Uranus is quite close to Venus, and so finadable with binoculars, particularly with the 15×70 pair we bought for comet ISON (but then never saw comet ISON). So, tonight I saw Uranus for the first time.

Some people can allegedly see Uranus with the naked eye; I certainly can’t.  And with tonight’s slightly hazy sky, it was a very faint dot, even with binoculars.

Phil Plait’s photo of Venus and Uranus

I didn't manage a full four planet night this time, as Mars was too low by the time I went out, but still.  Six planets!

Thursday, 5 March 2015

academic stress

Here’s an interesting article about stress in academia, from last year:
Mental health problems are on the rise among UK academics amid the pressures of greater job insecurity, constant demand for results and an increasingly marketised higher education system.

University counselling staff and workplace health experts have seen a steady increase in numbers seeking help for mental health problems over the past decade, with research indicating nearly half of academics show symptoms of psychological distress.

In the past, I’ve wondered aloud: the academic contract is for a 38 hour week [hahahahahaha]; the academic culture is one of long hours [60 is typical; 80-90 not unknown]; promotion criteria seem to be based on expectations that are possible within that culture, but not within that contract; when are we going to have the first claim for constructive dismissal? 

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Monday, 2 March 2015


Here’s another book for the wishlist:
The word-hoard: Robert Macfarlane on rewilding our language of landscape

For decades the leading nature writer has been collecting unusual words for landscapes and natural phenomena – from aquabob to zawn. It’s a lexicon we need to cherish in an age when a junior dictionary finds room for ‘broadband’ but has no place for ‘bluebell’

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Sunday, 1 March 2015

(re)discovering the year

We've had our solar PV system for over a year now.  One of the many plots we make is its output, measured every five minutes through the day, for each day:

(The horizontal time axis runs from 3:00am to 9:00pm GMT, and the vertical axis runs from January 2014 to February 2015.  The colour indicates the average production in kW in the five minute interval.)

Hey, there's a pattern!

We started generating in January last year, as the days were getting longer.  The changing day length is clearly visible.  Where we live, sunrise to sunset is a mere 7 hours 41 minutes on 21 December, and a whopping 16 hours 48 minutes on June 21.  I got those times from a website, not our generation data.  The system doesn't switch on exactly at sunrise and switch off exactly at sunset: it depends on clouds and scattering and stuff.  But the sinusoidal trend over the year is clear from the chart.

We get more power in June not only because the sun is up for longer, but it also generates more at peak, because the sun is higher in the sky, shining down fully onto the panels, not at an oblique angle.  So last June we saw this average over the month:

(Here the horizontal time axis runs from 3:00am to 9:00pm GMT, and the vertical axis runs from zero to 8kW.  The orange regions indicate the minimum, lower quartile, median, upper quartile, and maximum generation at that time, over the month. The black line indicates the monthly mean generation at that time.  The number is the average kWh production per day.)

The statistics show how variable the generation is.  On the best June day we got 53.63 kWh, but on the worst June day generated only 18.35 kWh.

Come December the generation plot looked like this, narrower and lower, with only a third the average generation:

There is still massive variation, from 27.63 kWh to a minuscule 0.34 kWh (it barely seemed to get light at all that day!)

But even an average of 12 kWh/day is a lot better than nothing!

Saturday, 28 February 2015

only one remains

A poignant juxtaposition:

(via BoingBoing)

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Friday, 27 February 2015

Leonard Nimoy, 1931-2015

Live long, and prosper.

From the sublime...
... to the ridiculous.

Saturday, 21 February 2015

wandering stars

The moon, Venus and Mars are in quite different positions from yesterday’s conjunction.  The moon has moved significantly, and the Venus–Mars separation has approximately halved.

Yes, of course that’s a spaceship in our garden.

The photo was taken with a Canon EOS20D; the moon, Venus and Mars (above and to the right of Venus) are real, the other little dots are post-processing artefacts.  Next time, we know to use a tripod!