SunPower (US) Questions

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I don't understand that. Why is 52 = 127?

Now I do understand that. "Quadrantal Bearings"
I have a little awk script for parsing N/S d m s E/E to 360 decimal.
Thanks for kicking me in that direction.

I don't know why I have never done that before. That's so much easier than
trying to plot the sun exactly at solar midday, or making an east-west line
with a series of plots, or staring at the hour hand on my watch ...
There happens to be a skinny tree directly north of the corner of the deck.
A permanent stake ;-)
I also confirmed that my compass was pointing in the right direction,

Thanks!
Two new things in one day!
I think I'll go back to bed now.

 

[daestrom]

Now I do understand that. "Quadrantal Bearings"
I have a little awk script for parsing N/S d m s E/E to 360 decimal.
Thanks for kicking me in that direction.


I don't know why I have never done that before. That's so much easier
than
trying to plot the sun exactly at solar midday, or making an east-west
line
with a series of plots, or staring at the hour hand on my watch ...
There happens to be a skinny tree directly north of the corner of the
deck.
A permanent stake ;-)
I also confirmed that my compass was pointing in the right direction,

Thanks!

No problem. I studied celestial navigation in my youth. Found it
fascinating how the sailing ships could find their way with a sextant, a
log, and a copy of 'Bowditch' ;-) Have taught all my kids a little 'star
gazing' over the years as well.

daestrom

 

[[email protected]]

I don't know why I have never done that before. That's so much easier than
trying to plot the sun exactly at solar midday, or making an east-west line
with a series of plots, or staring at the hour hand on my watch ...
There happens to be a skinny tree directly north of the corner of the deck.
A permanent stake ;-)
I also confirmed that my compass was pointing in the right direction,

I went outside this morning with my large protractor and marked the angle
of the building verses my plotted north line. Everything agrees within one
degree, which is better than I can eyeball Polaris against a point on the
building to a rock on the ground. I am "square" with the street and one
neighbor's fence. The other neighbor's fence is at an obvious angle.

I ran outside at 12:55pm PDT to find the solar noon marking of north.
I had put a couple of rocks down last night, and noted the one tree.
Today, with the sun shining, I tried to put more rocks down... Polaris
doesn't move much, but solar midday is a fleeting opportunity.

By the time it occurred to me to let a plumb bob string cast a shadow on the
line I had drawn on the deck from the Polaris lineup, it was obviously
off kilter, and moving away quickly.

I also tried lining up the tree and the point on my deck from farther out,
and projecting a point with my GPS due south. That isn't particularly
satisfying. The GPS started out at an estimated accuracy of 117 feet, and
settled in at 17 feet.

The GPS is wonderful for getting within sight of an object, but it isn't
great for survey work. http://www.confluence.org/photo.php?visitid=8914
picture 5 shows someone else visiting my pile of rocks in the middle of a
large open plateau.

I'm going to chisel a north marker in the sidewalk ;-)

 

[[email protected]]

No problem. I studied celestial navigation in my youth. Found it
fascinating how the sailing ships could find their way with a sextant, a
log, and a copy of 'Bowditch' ;-) Have taught all my kids a little 'star
gazing' over the years as well.

My daughter and her friends stargaze, and I have always been able to find
the north star. I had never considered it as a precision instrument
before, but it is at least as good as my compass.

Sighting over the house last night, I used too short of a distance... I
stood with Polaris sitting on the roof, which left me only about ten feet
back. Looking from the deck over that one tree gave me a distance of about
100 feet, so I think that is a more accurate reading.

 

[[email protected]]

http://www.sunpowergeo.com ?

I got a call from SunPowerGeo today. They have scheduled installation to
start on November 29. They have a projection to receive the necessary
Kyocera panels by then, but indicate that they are in short supply.

 

[daestrom]

I went outside this morning with my large protractor and marked the angle
of the building verses my plotted north line. Everything agrees within
one
degree, which is better than I can eyeball Polaris against a point on the
building to a rock on the ground. I am "square" with the street and one
neighbor's fence. The other neighbor's fence is at an obvious angle.

I ran outside at 12:55pm PDT to find the solar noon marking of north.
I had put a couple of rocks down last night, and noted the one tree.
Today, with the sun shining, I tried to put more rocks down... Polaris
doesn't move much, but solar midday is a fleeting opportunity.

By the time it occurred to me to let a plumb bob string cast a shadow on
the
line I had drawn on the deck from the Polaris lineup, it was obviously
off kilter, and moving away quickly.

I also tried lining up the tree and the point on my deck from farther out,
and projecting a point with my GPS due south. That isn't particularly
satisfying. The GPS started out at an estimated accuracy of 117 feet, and
settled in at 17 feet.

The GPS is wonderful for getting within sight of an object, but it isn't
great for survey work. http://www.confluence.org/photo.php?visitid=8914
picture 5 shows someone else visiting my pile of rocks in the middle of a
large open plateau.

I'm going to chisel a north marker in the sidewalk ;-)

Well, if you're going to go to all that trouble, you might go ahead and
account for Polaris not being *exactly* due north. It actually 'orbits'
true north in a tiny, tiny circle. The radius of the circle is just under 1
degree. So at two times during the night/day, it can be almost 1 degree
off, and twice a day it is *exactly* dead north.

http://www.absoluteastronomy.com/encyclopedia/p/po/polaris.htm

It's celestial coordinates are Right Ascension 2 hr 31 minutes and
declination of 89 degrees 15 minutes. The declination tells us that it
actually orbits true north in a tiny, 45 minute radius circle.

Since Polaris has a 'Right Ascension' of 2 hr 31 minutes, it will be at the
'bottom' of its tiny circle when the 'dipper' portion of the Big Dipper is
at about the '10:30' position when you look up at it. So to be *really*
accurate, you could wait and go out sometime in the middle of the night when
the Big Dipper is in that position. Or, when the dipper portion of the Big
Dipper is at the '4:30' position, polaris will be at the 'top' of its circle
and again be exactly true north.

If you have a tree or plumb bob to help you 'drop the star to the horizon',
and you use a fairly good distance between your siting and the tree/bob, you
can get a *very* accurate true north with these rather 'crude' instruments.

Have fun....

daestrom

 

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Well, if you're going to go to all that trouble, you might go ahead and
account for Polaris not being *exactly* due north. It actually 'orbits'
true north in a tiny, tiny circle. The radius of the circle is just
under 1 degree. So at two times during the night/day, it can be almost 1
degree off, and twice a day it is *exactly* dead north.

I don't have a one degree calibrated eyeball ;-)


Thanks. I think I'll have another look. Oddly enough, there is just
enough overcast that I can't seem to locate the Big Dipper, but I can see
the Polaris... it's always in the same spot, and kind of familiar ;-)