Ralf

The equatorial gnomon analemma dimensions are a function only of the EoT and 
the dial radius.  The longitudinal correction is obtained by rotating the dial 
hours.

There are several ways of implementing analemmatic gnomons,  I will send you 
privately an Excel program which does the calculation.

Brian Albinson
3441 Wellington Crescent, North Vancouver
BC,  V7R 3B3
Phone 604 980 3475
  ----- Original Message ----- 
  From: Ralf Jung 
  To: [email protected] 
  Sent: Sunday, March 21, 2010 8:23 AM
  Subject: Analemma for Equatorial Sundial


  dear sundial expert's,

  I want to build a equatorial sundial with a corrector on the gnomon. Like the 
one at Cosmos Observatory Lasstrop (there is a picture at 
http://www.fransmaes.nl/zonnewijzers/welcome-e.htm => Pole style:equatorial => 
armillary spheres netherlands). I read a view articles how to construct this 
kind of gnomon (e.g. http://www.mysundial.ca/tsp/analemmic_sundial.html). But 
still there is question which I can not answer. If I construct an analemma 
(12:00 UT) for the location (longitude 8° 44' E; latitude 48° 35' N) with the 
ephemeride from the U.S. Naval Observatory then this analemma is tilted to the 
right sight and not perpendicularly. What are the right numbers to calculate 
the gnomon-corrector (include longitude)? 
  1. y = declination; x = EOT + longitude (15°- 8° 44')*4
  2. y = declination; x = azimuth from the ephemeride
  For clarification, my question is not about trigonometry.

  thanks

  ralf 



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