I am fascinated by astronomy since the first time I looked to the night sky. Recently, I bought a 8" Newtonian telescope that came with a Dobsonian mount. It's a nice mount (cheap, portable and very easy to use), but to get what you want to see, you need to know the sky like the palm of your hands (which can be a problem to a beginner like me..!).

To help you to know the sky, there are several software's you can use and stellarium is my favorite one. Stellarium is an open source project with a lot of helpful astronomy features, including a plugin that allow a connection between a computer and a telescope controller (like celestron, meade or sky-watcher).

After a couple of nights using my telescope, I realized that it should be helpful if, at any moment, I can compare my telescope position with the position of the target that I am looking for.

You can say: Yeah! Buy a goto telescope and you will see your problem solved! Well, you are absolutely right!

However, because of my electrical background and because I like to consider myself hobbyist, my first thought was: - I can (and I will) build a DIY controller for my telescope.

Why build a controller instead buying a ready to use one?

It will be a lot of fun trying to do something new;

It's a good contribution to learn a lot of new things (otherwise skipped by using a ready to use solution) like: alt-azimuth and celestial coordinates, local sideral time, earth movement, spherical trigonometry;

You can control your own budget and keep it below 50USD;

Your telescope will be customized to fit your needs;

Your telescope will become "famous" among your friends;

If you are not interested to spend thousands in a go-to mount, this will give you a really good help when you start to point your telescope to the sky;

This instructable will guide you, step by step, how to complete your own controller using Stellarium (astronomy software) and Arduino (open-source prototyping platform based on easy-to-use hardware and software).

And, why Arduino? Well, there is not a simple answer for that... I personally prefer Arduino for several reasons, including:

It's cheap and easy to find;

It's an open source project;

Have a huge community and tons of information online;

It's easy to find libraries that can help you using a lot of different things;

You can easily add a lot of shields and sensors specially designed for Arduino, or you can adapt others;

For most of the projects, it's reliable enough;

It's very versatile and flexible (I/O ports, communication, etc);

It's user friendly;

Uses "C" as programming language;

It's easy to interact with I/O ports, both digital and analog;

Now, that you are already introduced to this "little" project, a summary of what you need to do is:

Find a way to place 2 position sensors (encoders) to read azimuth and altitude;

Connect them to a controller like Arduino;

Build the hardware interface (elementary electronics);

Program the controller to calculate coordinates and communicate with a computer;

Install and config Stellarium to work together with your controller;

It will cost you some time and (a lot...of) patience, but you will be pleased with the result. Watch the video above and...

- It will be worth it!