my A to Z - every day of the challenge I will find a word by flinging my finger into my American Heritage Dictionary and then riff on it. The posts may be essays or poems or stories or memories. Who knows what will happen when we give Serendipity her wanton way?
Planisphere - n. A representation of a sphere or part of a sphere on a plane surface. 2. astron. A polar projection of the celestial sphere on a chart equipped with an adjustable overlay to show the stars visible at a particular time and place.
"Whatcha got there?" The girl was wearing ripped black tights with an enormous black t-shirt, Doc Martins and about a thousand piercings. Alex tried not to judge but why oh why right now did she have to come over? He was so close to figuring this out and now this dipsoid was going to ruin everything.
"A planisphere." Maybe that would turn her attention away. Sounded boring. Not to Alex though - to Alex it was thrilling.
"Cool. What does it do?"
Argghh! Oh well, she asked for it.
"Using this projection the sky is charted centered on one of the celestial poles while circles of equal declination lie equidistant from each other and from the poles. The shapes of the constellations are proportionally correct in a straight line from the centre outwards, but at right angles to this direction. there is considerable distortion. That distortion will be worse as the distance to the pole gets greater. If you were to look at the famous constellation of Orion in this projection and compare this to the real Orion, you could clearly see this distortion. It is the only disadvantage of this projection."
" Oh it's a polar azimuthal equidistant projection! Right. Lots of problems there but I suppose you've tried the stereographic projection? It solves this problem but then it introduces another. I suppose since we're in a moderate latitude you might as well use it as the stereographic."
She rocked back on her heels and sighed.
Alex was without words - he couldn't have spoken if he'd had a gun at his head.
"Well thanks for showing me. I'm new at the university and mostly I've found people so condescending you know? Glad that you're not all like that. I'll leave you to your work. See you around."
Mapping stars didn't seem quite as much fun as it had a moment ago. Alex put his head down and made a few more calculations. Science - now there was something you could trust.