Comments on: Calculate Tree Height To See If Panels Will Be Shaded

By: Eddie

Eddie — Fri, 27 Jul 2007 18:43:01 +0000

I do not remember from his readings.
From geometry on my whiteboard and vague memories from reading books about sundials:

Neglecting the tilt of the earth, the noon time sun is (90 - latitude) degrees above the horizon. So for us that is almost exactly 50 degrees.

Factor in the tilt of the earth’s axis of rotation (23.5 degrees?), and the summer and winter extremes will be +/- 23.5 degrees of the (90 - latitude) number. That’s 26.5 to 73.5 degrees (winter to summer).

So I think that your 26 degree number is correct for the ‘winter low’ of the sun.

At least cottonwoods do not have leaves in the winter! (perhaps only partial shading….)

By: Dave

Dave — Fri, 27 Jul 2007 14:55:39 +0000

Eddie,

That is a very cool looking tool.

I am working on figuring out what the angle of the sun is at our latitude in our town, do you remember what that was from his readings - was it 26 degrees?

I will answer your questions on my next post.

By: Eddie

Eddie — Fri, 27 Jul 2007 14:42:46 +0000

Holy similar triangles Dave! I like the tree height estimation method. Next I’ll expect you to estimate the radius of the earth based on shadow observations at noon….

You need to get a hold of a solmetric or some other shadow analysis tool. David Fosdeck of REC Solar used one when he checked out my roof. It’s a cool product (basically integrates a PDA, a digital camera w/ fish-eye lens, a compass, and a level). I thought that the method for displaying the results (what part of roof is shaded and when (time of day and time of year)) was very cool (i.e. lots of info in one ‘image’)

Where is this tree relative to your house? (how far, what direction)