How to Align your Heliostat for the Visual Basic Sun Tracker Program

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This page will show you how you need to align your heliostat for it to work with the Sun Tracker program. Note: The process for setting up a Heliostat for the Arduino Sun Tracking / Heliostat program isn’t the same as that outlined here. When I have the time, I’ll have to write separate page for it. (Or maybe I already have and just forgot to remove this text. Check the Heliostat Projects page to see if it’s there)

Essentially, all you have to do is make both the heliostat’s altitude and its azimuth equal zero degrees. The heliostat’s altitude equals zero when the mirror is plumb, and its azimuth equals zero when the mirror runs parallel to geographic east and west.

This is the position the Sun Tracker program assumes the heliostat is located when it is first started.

The process is fairly easy to accomplish, but it might seem daunting if you’ve never done it before. Just take it one step at a time, and you should be fine.

Note: This is not the type of heliostat which is set on an equatorial mount, and this page does not cover aligning such a device.

What You will Need

Before you can get started, you will need the following items.

A level
A map compass
Around 10′ of string (I’m using an old chalk box)

Additionally, you will need to know the magnetic declination for your area. This can be found at the following link… http://www.ngdc.noaa.gov/geomagmodels/Declination.jsp

According to the above site, the magnetic declination where I live is  9° 52′ W. If you don’t already know, 9° 52′ is read as 9 degrees 52 arc minutes. This is not the same 9.52 degrees like you might have thought. The magnetic declination at the above site is written in degrees minutes and seconds.

To switch to decimal degrees, you can use this site. http://id.mind.net/~zona/mmts/trigonometryRealms/degMinSec/degMinSec.htm (Scroll Down the Page to see where the calculator is)

Adjusting for Magnetic Declination

For our purposes, we will first need to set the compass at 90 degrees.

My magnetic declination is pretty close to 10 degrees west, but yours will likely be different. Using mine as an example, the entire compass is turned until the needle points 10 degrees west of north.

The red “N” (not the needle) now points toward geographic north.

More importantly though, the edge of the compass is now in line with geographic east and west.

Setting the Heliostat’s Azimuth to Zero Degrees

For this example, I will be aligning one of the prototype heliostats that I built. (At the time of this writing, I haven’t actually built the permanent one yet.) The reflection from the mirror makes it hard to see what’s going on, so I flipped it and made the back side face outward in the rest of the pictures.

In the picture below, I have the compass aligned so that it’s edge runs parallel with geographic east and west like I told you to do above. With one end attached to the heliostat, the string is used to extend the edge of the compass.

Here, the string is indeed parallel with east and west, but the heliostat is not.

Note: Although it is possible to hold the edge of the compass against the mirror to align the heliostat, I have learned from experience that it is better to keep the compass far away from anything metallic which might unknowingly attract the needle.

In the picture below, the heliostat has been turned, and the mirror now runs parallel with the string(/east and west). The heliostat’s azimuth has been successfully set at zero.

At this point, you should make a mark somewhere on the heliostat so that you can easily return it to this position without the compass and string.

Setting the Heliostat’s Altitude to Zero Degrees

Setting the Heliostat’s altitude to zero degrees is very simple. Just take a level and adjust the mirror until it is plumb.

You’re Done!

And that’s all there is to it. You now have a heliostat that has been successfully aligned.

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