Can anyone tell me where I can get one of these...
Comments

It is not hard to make one... You just need to decide what is "best" and "good" for you...
To 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/sinecosinetangentchart.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
BillNear San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset 
Got mine off eBay.
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 Trimetric, 460 Ah. 24 volt LiFePo4 battery bank. Plenty of Baja Sea of Cortez sunshine.

littleharbor2 said:Got mine off eBay.

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 Trimetric, 460 Ah. 24 volt LiFePo4 battery bank. Plenty of Baja Sea of Cortez sunshine.

littleharbor2 said: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.

BB. said:It is not hard to make one... You just need to decide what is "best" and "good" for you...
To 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/sinecosinetangentchart.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
Bill

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.Offgrid.
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 
littleharbor2 said:Got mine off eBay.

Estragon said: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.

Tape a pencil (or a straw) to the edge of your panel. and aim panel for no shadowPowerfab 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 SO59 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
solar: http://tinyurl.com/LMRSolar
gen: http://tinyurl.com/LMRLister , 
Another option is a suction cup dart for a toy gun https://www.ebay.com/itm/3SETSTOYSUCTIONDARTGUN/202590110364?hash=item2f2b4fc29c:g:5nEAAOSw27FbLaM7 simply stick on the surface of the module.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.
BillNear 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 Trimetric, 460 Ah. 24 volt LiFePo4 battery bank. Plenty of Baja Sea of Cortez sunshine.

What are the radiuses (or diameter) of the excellent/good/bad circles?
BillNear San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset 
15/16", 1 13/32" and 1 7/8"
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 Trimetric, 460 Ah. 24 volt LiFePo4 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 Trimetric, 460 Ah. 24 volt LiFePo4 battery bank. Plenty of Baja Sea of Cortez sunshine.

Diameter or radius?
BillNear San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset 
Center point, outward, radius, correct?
Diameter, 1 7/8", 2 13/16", 3 3/4".
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 Trimetric, 460 Ah. 24 volt LiFePo4 battery bank. Plenty of Baja Sea of Cortez sunshine.

Radius, correct.
InvTan ((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 (018 degrees great, 1844 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
BillNear San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
Categories
 All Categories
 219 Forum & Website
 127 Solar Forum News and Announcements
 1.3K Solar News, Reviews, & Product Announcements
 187 Solar Information links & sources, event announcements
 885 Solar Product Reviews & Opinions
 254 Solar Skeptics, Hype, & Scams Corner
 22.3K Solar Electric Power, Wind Power & Balance of System
 3.5K General Solar Power Topics
 6.7K Solar Beginners Corner
 1K PV Installers Forum  NEC, Wiring, Installation
 2K Advanced Solar Electric Technical Forum
 5.5K Off Grid Solar & Battery Systems
 422 Caravan, Recreational Vehicle, and Marine Power Systems
 1.1K Grid Tie and Grid Interactive Systems
 647 Solar Water Pumping
 814 Wind Power Generation
 621 Energy Use & Conservation
 604 Discussion Forums/Café
 299 In the WeedsMember's Choice
 74 Construction
 124 New Battery Technologies
 107 Old Battery Tech Discussions
 3.8K Solar News  Automatic Feed
 3.8K Solar Energy News RSS Feed