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description: Have you ever wanted to build a telescope by yourself? What would be the challenges and the outcomes? If you would like to know the answers to those and more questions, you will love this article, which is an interview about this confection process.
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This article is written in an interview format. The credited author was interviewed by the STEM Guy club with the questions presented in each topic. His answers were registered in Brazilian Portuguese and translated by our team.
A telescope, just like any scientific instrument, needs to be well-made and precise. In Brazil, the diversity of good and accessible telescopes is scarce, leaving us with two choices:
- Save enough money to buy one; or
- Accept the challenge of learning how to create your own telescope, in which the quality level is defined by your effort, time investment, knowledge, and — most importantly — patience.
I have chosen the second option.
I don't believe I am building this telescope alone, because everything I know is thanks to the websites Observatório Phoenix and Stellafane, and to my friend Jhonathan, who helps me to think in the confection process. This support was — and still is — really important to me, and I strongly admire the people and organizations that share knowledge; we need more of this in the world.
The initial concern was the possibility of getting all the needed inputs and not being able to develop the project. Because of that, I have read several times the instructions of all steps. Even tough, I've made mistakes and had many questions; it is part of the learning process, and the important thing is not giving up.
The confection of the optical elements were by far the most challenging task in the construction of the equipment, from the cut of circular pieces to the final polishing. The optical drawing of the glass requires a perfection in the nanometer scale; there are no apparatus in a construction store with that measurable power. The tests are made by indirect methods, such as looking for the Ronchi grating in the mirror or cutting the light ray of the mirror with the Foucault knife. It's complicated!
I have finished the optical part, which is the longest and most difficult one. The glass surfaces are already well polished. The primary spherical mirror has already been analyzed in the Foucault test and is within the quality pattern; the secondary mirror is an optical plane and was tested by interferometry, also resulting in the expected range. Now, it's necessary to send them to a laboratory to get aluminized. I have already gotten the mirror supports and the focuser; now, it's needed to create the tube and the mount.
Besides the equipment, I have gained experience in polishing of optical surfaces and a more substantial knowledge about optical physics. I have also gained more enthusiasm to keep creating and trying to make bigger and bigger telescopes.