The March equinox was yesterday and today is the end day of mistYmuse 20/21: four months after mYm 20/21 started, and five months after False Dawn Week! I hope it helped you through the traditionally toughest four or five months in the UK and northern hemisphere year.
This is one of three posts I hope to bring you today, bringing the biggest mistYmuse ever to a fireworks finale!
Ancient Astronomy Angle
I wasn’t awake for this morning’s sunrise, but wasn’t too bothered, as was for last year’s, and can see from this 20/3/20 photo how much the sun is further along the horizon from the three buildings it rose near on March 12th this year (as seen in photo below it).
On March 6th (last year), for the most iconic of mornings, the sun rose the other side of the three buildings:
On February 28th, this year, those three buildings are nearly out of the photo, and the hospital (circle above) becomes the next landmark;
On the 17th of February (last year) the sun was over the city centre, with the hospital (circled) nearly out of the photo. That tree has now been cut, exposing the pylon behind it.
A week earlier (on February 10th this year), it rose near the pylon, between the city centre and the south of the city across the River Aire:
On January 29th it had been below the city centre altogether.
Happy mistYmuse ist day, as the m departs with only 3 days to go until mistYmuse Y day; this isn’t a mystery worthy of Scooby; and the greenYgrey world solstice day! This is my contribution to amateur astronomy; the old way; showing how the sunrise (really: our first view of the sun) has started its journey back up the eastern horizon, from its most southerly midwinter point around December 21st (it was cloudy then, so the middle photo is from the 22nd). The top photo is from November 27th, and the bottom yesterday, both 25/26 days either side of the middle one on December 22nd. In the middle midwinter one, the sun rises in the v, to the right of the big tree, while in the other two it rises to the left of the big tree.
To my brain, it still seems strange that the sun goes back up the eastern horizon, even though we’re going around the sun in a circle (now at about 11 o’clock according to an orrery, compared to 1 o’clock in November):
But, thinking about it, that’s because my brain is still thinking of the humanistic sun ‘rise’, rather than the heliocentric our ‘first view of the sun’. ‘Sunrise’ is of course because of our planet’s spin each ‘day’, rather than our orbit around the sun, which gives us our ‘year’ and ‘seasons’.
The sunrise travelling back up the ‘eastern horizon’ is really that we see it earlier in the northern hemisphere as our planet’s stationary axis tilt is pointing more towards the sun for half of the orbit (measured in our calendar as from December to June, with equal half way with the southern hemisphere in March and September).
The orrery shows the norther hemisphere’s six months of more sunlight are when Earth is ‘south’ of the sun, which makes sense when you think about it (not at first for me!), as we are tipped towards the sun then.
Milky Way View
Another way to check this, and get a better idea of how Earth’s 23.4/5 axis tilt and solar orbit directs our view and time, is to look out from the sun, into space. Our planet and solar system is in the west of our Milky Way galaxy.
So, sometimes here on Earth, we have a clear view of most of the Milky Way, and other times we’re on the other side of the sun for the best views (of more of the galaxy). As shown on that website, our best views of the Milky Way are just coming up, from February to October, when we’ll be on the inside of the sun during our solar system (in the above image at about 6/7 o’clock) orbit for closer dark sky views of the centre of our galaxy.
That’s why different constellations are visible at different times of the year, and in different parts of the sky. Ursa Major looked quite low in the northern sky during the summer when I used it to see comet neowise, and now it looks directly above us. That’s because Earth’s position to it has changed, rather than the ‘night sky’ changing. And the same is true of the ‘sunrise’.
Sorry, if the above dragged on a bit, but I’m still working it out myself too!!