Cosine is the angle of the ratio of opposite over hypotenuse.

One way to lay out what you want (i.e., a circle at 26 degrees) would be to use a protractor to make the angle and use the distance between the "sight" and the target, then draw a vertical line to the angle. That distance would be the radius of the circle.

Or you can use the Tangent function. Tangent is the angle of the opposite over the adjacent. From above Cos 26d = 0.90 as our "best/good" target line, Tan 26 degrees = 0.488 and the radius would be:

Tan (d) = O/A

O = Tan (d) * A

Example of Tan (26 degrees) = 0.488

Use A = 5 inches between peephole sight and target

O = Tan (26) * 5 inches = 0.488 * 5 " = 2.44 inch radius circle for target

If I remember my trig...

-Bill

Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset

2.1 Kw Suntech 175 mono, Classic 200, Trace SW 4024 ( 15 years old but brand new out of sealed factory box Jan. 2015), Bogart Tri-metric, 540 ah @24 volt AGM battery bank. Plenty of Baja Sea of Cortez sunshine.

It's called a SunStalker (one word) manual solar tracker. There's another item of the same name out there but you should be able to locate it online.

2.1 Kw Suntech 175 mono, Classic 200, Trace SW 4024 ( 15 years old but brand new out of sealed factory box Jan. 2015), Bogart Tri-metric, 540 ah @24 volt AGM battery bank. Plenty of Baja Sea of Cortez sunshine.

Cosine is the angle of the ratio of opposite over hypotenuse.

One way to lay out what you want (i.e., a circle at 26 degrees) would be to use a protractor to make the angle and use the distance between the "sight" and the target, then draw a vertical line to the angle. That distance would be the radius of the circle.

Or you can use the Tangent function. Tangent is the angle of the opposite over the adjacent. From above Cos 26d = 0.90 as our "best/good" target line, Tan 26 degrees = 0.488 and the radius would be:

Tan (d) = O/A

O = Tan (d) * A

Example of Tan (26 degrees) = 0.488

Use A = 5 inches between peephole sight and target

O = Tan (26) * 5 inches = 0.488 * 5 " = 2.44 inch radius circle for target

If I remember my trig...

-Bill

Bill, my sister the math genius could do this. I'm more like a monkey with a soldering when I build guitar amps.

It seems to me something like a long nail at right angles through a piece of wood would do much the same thing. Tilt the panel to make the shadow disappear at noon.

Off-grid. Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter

Do you mind measuring the dimensions of yours and sending them? I can do the drawings on the computer (in Adobe Illustrator) if I just know the dimensions. Thank you. If you mind, that's ok too.

It seems to me something like a long nail at right angles through a piece of wood would do much the same thing. Tilt the panel to make the shadow disappear at noon.

I'd need to see a visual representation...I'm old...

Tape a pencil (or a straw) to the edge of your panel. and aim panel for no shadow

Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048
inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A
NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole |
Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor
(1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
|| Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
|| VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

1500W, 6× Schutten 250W Poly panels , Schneider MPPT 60 150 CC, Schneider SW 2524 inverter, 400Ah LFP 24V nominal battery with Battery Bodyguard BMS Second system 1890W 3 × 300W No name brand poly, 3×330 Sunsolar Poly panels, Morningstar TS 60 PWM controller, no name 2000W inverter 400Ah LFP 24V nominal battery with Daly BMS, used for water pumping and day time air conditioning. 5Kw Yanmar clone single cylinder air cooled diesel generator for rare emergency charging and welding.

Tell me the distance between the sight (hole) and the target. And tell me the percentage of 100% harvest (i.e., 10 degrees off center, Cos 10 degrees = 0.985 = 98.5% or 1.5% less than perfect.

And I will tell you the radius of each circular boundary.

-Bill

Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset

Upper and lower surfaces are 3 7/8" square and they are 2 7/8" apart. The pinhole is 1/8"

2.1 Kw Suntech 175 mono, Classic 200, Trace SW 4024 ( 15 years old but brand new out of sealed factory box Jan. 2015), Bogart Tri-metric, 540 ah @24 volt AGM battery bank. Plenty of Baja Sea of Cortez sunshine.

2.1 Kw Suntech 175 mono, Classic 200, Trace SW 4024 ( 15 years old but brand new out of sealed factory box Jan. 2015), Bogart Tri-metric, 540 ah @24 volt AGM battery bank. Plenty of Baja Sea of Cortez sunshine.

BTW, The bottom plane is 5 1/2" long with a sharp 180 degree return which is designed to hook the backside of the solar panel frame. It came with one of those spring steel paper clip things to pinch and hold it in place.

2.1 Kw Suntech 175 mono, Classic 200, Trace SW 4024 ( 15 years old but brand new out of sealed factory box Jan. 2015), Bogart Tri-metric, 540 ah @24 volt AGM battery bank. Plenty of Baja Sea of Cortez sunshine.

2.1 Kw Suntech 175 mono, Classic 200, Trace SW 4024 ( 15 years old but brand new out of sealed factory box Jan. 2015), Bogart Tri-metric, 540 ah @24 volt AGM battery bank. Plenty of Baja Sea of Cortez sunshine.

So, if you like those numbers as your excellent/good/poor harvest numbers (0-18 degrees great, 18-44 degrees good, over 44 degrees off sun is poor), then you can put your two cards 2 7/8 inches apart. Then set a compass to LittleHarbor2's two radiuses and draw the two circles.

If you have a different spacing between the two cards, then simply multiply the actual card to card spacing by:

## Comments

32,229adminTo calculate the energy from the sun, offset by the angle of the panel to the sun is Cosine Angle (degrees) ...

So, a panel that is pointing directly at the sun is Cos 0 degrees = 1.00 ... I.e., 100% of the available sun's energy hits the panel.

Cosine 10 degrees = 0.98 or 98% of the available energy.

Say you decide 90% of the solar energy is the boundary between Best and Good... That would be invCos 0.9 = 26 degrees

And if you decide that 0.71 (71%) is good/bad boundary, that would be 45 degrees.

Here is a handy chart if you don't have an engineering calculator:

https://www.mathwarehouse.com/trigonometry/sine-cosine-tangent-chart.php

Cosine is the angle of the ratio of opposite over hypotenuse.

One way to lay out what you want (i.e., a circle at 26 degrees) would be to use a protractor to make the angle and use the distance between the "sight" and the target, then draw a vertical line to the angle. That distance would be the radius of the circle.

Or you can use the Tangent function. Tangent is the angle of the opposite over the adjacent. From above Cos 26d = 0.90 as our "best/good" target line, Tan 26 degrees = 0.488 and the radius would be:

- Tan (d) = O/A
- O = Tan (d) * A
- Example of Tan (26 degrees) = 0.488
- Use A = 5 inches between peephole sight and target
- O = Tan (26) * 5 inches = 0.488 * 5 " = 2.44 inch radius circle for target

If I remember my trig...-Bill

1,639✭✭✭✭2.1 Kw Suntech 175 mono, Classic 200, Trace SW 4024 ( 15 years old but brand new out of sealed factory box Jan. 2015), Bogart Tri-metric, 540 ah @24 volt AGM battery bank. Plenty of Baja Sea of Cortez sunshine.

128✭✭✭1,639✭✭✭✭2.1 Kw Suntech 175 mono, Classic 200, Trace SW 4024 ( 15 years old but brand new out of sealed factory box Jan. 2015), Bogart Tri-metric, 540 ah @24 volt AGM battery bank. Plenty of Baja Sea of Cortez sunshine.

128✭✭✭128✭✭✭4,495✭✭✭✭✭Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer

Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter

128✭✭✭128✭✭✭9,465✭✭✭✭✭|| Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||

|| VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

solar: http://tinyurl.com/LMR-Solar

gen: http://tinyurl.com/LMR-Lister ,

3,854✭✭✭✭✭✭Second system 1890W 3 × 300W No name brand poly, 3×330 Sunsolar Poly panels, Morningstar TS 60 PWM controller, no name 2000W inverter 400Ah LFP 24V nominal battery with Daly BMS, used for water pumping and day time air conditioning.

5Kw Yanmar clone single cylinder air cooled diesel generator for rare emergency charging and welding.

32,229adminAnd I will tell you the radius of each circular boundary.

-Bill

1,639✭✭✭✭2.1 Kw Suntech 175 mono, Classic 200, Trace SW 4024 ( 15 years old but brand new out of sealed factory box Jan. 2015), Bogart Tri-metric, 540 ah @24 volt AGM battery bank. Plenty of Baja Sea of Cortez sunshine.

32,229admin-Bill

1,639✭✭✭✭1,639✭✭✭✭32,229admin-Bill

1,639✭✭✭✭Diameter, 1 7/8", 2 13/16", 3 3/4".

32,229adminInvTan ((15/16) / (2 7/8)) = 18 Degrees

Cosine 18d = 0.951 = 95.1% harvest eff

InvTan ((2 13/16) / (2 7/8)) = 44.4 Degrees

Cosine 44.4d = 0.714 = 71.4% harvest eff

So, if you like those numbers as your excellent/good/poor harvest numbers (0-18 degrees great, 18-44 degrees good, over 44 degrees off sun is poor), then you can put your two cards 2 7/8 inches apart. Then set a compass to LittleHarbor2's two radiuses and draw the two circles.

If you have a different spacing between the two cards, then simply multiply the actual card to card spacing by:

((15/16) / (2 7/8)) = 0.3261 (excellent/good boundary)

((2 13/16) / (2 7/8)) = 0.9783 (good/poor boundary)

For example, if you have 5" spacing between cards, the first circle will be:

5" * 0.3261 = 1.63 inches = ~ 1 5/8 inches

And the second circle will be:

5" * 0.9783 = 4.891 inches = ~ 4 29/32 inches

-Bill