[LEAPSECS] Pinhole analemma

[Rob Seaman]

The Astronomy Picture of the Day for 2014 March 20 is a solargraphic pinhole analemma for Wrocław, Poland, as elegant an example as I've seen.  I admire the dedication of the photographers with this multiple exposure!

	http://apod.nasa.gov/apod/ap140320.html

The noon analemma is near vertical since Wrocław is just 2 degrees from the CET meridian.  Those to the left and right are an hour and a half before and after noon, meaning just a 15s daily clock error relative to mean solar time would skew one figure 8 on top of its neighbor.  While a fraction of a second secular error per day would be enough to show a discontinuity on the calendar date that the project began and ended since 1s/day is 6 minutes per year, a large fraction of the width of Earth's equation of time.

Conversation starters:

	• How would the picture differ if the pinhole shutter were timed by a sundial?
	• How if by sidereal clock?

Rob