Solar phenomena
A discussion in Another Place about leap seconds got me thinking about the Equation of Time again. It's been ages since I got in to that stuff about the position of the mean sun and the obliquity of the ecliptic, and it's lovely stuff.
It made me think I wanted to get a photo of the solar analemma. You could fairly easily job together a Raspberry Pi with its camera and write some trivial software to capture a photo at the same time every day for a year. Even better, it'd be almost no extra effort to take a photo at several times in each day so you could compare, say, the 9.30 analemma, the one at noon, and the one at 2.30. Then you could almost certainly automate the search for photos with the sun in, composite, job done.
Except you'd need to stick the kit firmly somewhere (a) with a clear view of the sun in the sky at all times of the year, (b) with a power supply, and (c) where it won't get moved, by adults or, more to the point, the kids. Which is not so easy. Also, it'd be yet another thing to babysit when we get a powercut, which is several times a year. And actually a Pi plus camera module plus card plus power supply plus wifi dongle adds up to real money.
The other solar phenomenon I've been thinking about recently is one I call 'The Hippo', because I've seen it lots the last few days, although I've seen it irregularly since I was a teenager. You can see The Hippo at any time of the year, but I tend to see it more at this time of year. The weather needs to be sunny, and the sun needs to be fairly low in the sky. You drive along in a car with the sun directly behind, and look at the shadow of the car in front of you on the road. It has a broad, rounded head with two sticky-out ears either side: a hippopotamus!
This entry crossposted to http://doug.dreamwidth.org/283787.html, where there are
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It made me think I wanted to get a photo of the solar analemma. You could fairly easily job together a Raspberry Pi with its camera and write some trivial software to capture a photo at the same time every day for a year. Even better, it'd be almost no extra effort to take a photo at several times in each day so you could compare, say, the 9.30 analemma, the one at noon, and the one at 2.30. Then you could almost certainly automate the search for photos with the sun in, composite, job done.
Except you'd need to stick the kit firmly somewhere (a) with a clear view of the sun in the sky at all times of the year, (b) with a power supply, and (c) where it won't get moved, by adults or, more to the point, the kids. Which is not so easy. Also, it'd be yet another thing to babysit when we get a powercut, which is several times a year. And actually a Pi plus camera module plus card plus power supply plus wifi dongle adds up to real money.
The other solar phenomenon I've been thinking about recently is one I call 'The Hippo', because I've seen it lots the last few days, although I've seen it irregularly since I was a teenager. You can see The Hippo at any time of the year, but I tend to see it more at this time of year. The weather needs to be sunny, and the sun needs to be fairly low in the sky. You drive along in a car with the sun directly behind, and look at the shadow of the car in front of you on the road. It has a broad, rounded head with two sticky-out ears either side: a hippopotamus!
This entry crossposted to http://doug.dreamwidth.org/283787.html, where there are
comment(s) not shown here.