(in
) said:
| Morris Dovey wrote:
||
||
|| I found http://science.howstuffworks.com/telescope5.htm which
|| explains az-el and equatorial mounts. Both require two-axis
|| adjustment. The collector will need to adjust at least +/- 23.5
|| degrees on one axis
|
| Yes, with a equatorial mount it will need to move from +23.5 to
| -23.5 and back once per year. I think that could be done by having
| the user adjust it once a week or so, assuming your collector can
| tollerate a error of 2 or 3 degrees in declination.
|
| If the collector takes the form of a U_shaped mirror shining on a
| pipe parrallel to the polar axis it should be VERY insensitive to
| declination errors.
Agreed - but if adjustment is needed, then why not make it
self-adjusting if that can be done at small cost and with high
reliability?
| Consider the horseshoe mount (split ring mount) in particular as
| it is very compact and can be designed without or with minimal
| counterweighting. The key to low-power tracking is balance so
| that you are not working against gravity. Telescopes weighing
| tens of tons can easily be moved by hand.
We're in agreement still. Gravity is not our friend here - and neither
is wind. What's needed is a well-balanced system that resists wind
forces and incorporates a closed-loop control system with adequate
negative feedback. [ Shazam! Did I really say that? ;-) ]
|| and at least 180 degrees on the other. I say "at least" because I
|| can't depend on any specialized skills on the part of the
|| installer. Remember - this thing is required to operate sunup to
|| sundown every day of the year without human assistance.
|
| Why does it need to operate for a whole year without human
| assistance?
|
| Wouldn't all day after being reset in the morning suffice?
Because Murphy is alive and well. Even reliable humans occasionally
screw up - and it generally works best to design systems that do
whatever with better than human reliability. With a focus
temperature in excess of Bradbury's Fahrenheit 452, I'd be very happy
if people just ignored it and enjoyed the benefits.
--
Morris Dovey
DeSoto Solar
DeSoto, Iowa USA
http://www.iedu.com/DeSoto