When I first got the idea of actually building a telescope in my mind, the first book I read was Amateur Telescope Making. To many this represents the pinnacle of telescope making books/guides. However, there are more out there than I once thought.
For example, here is the book on mirror making that my grandpa wrote back in the 60s. It was typed with a typewriter and the drawing were all made by him, which were really great drawings. This book is the simple way on how to build a 3 inch F-12 reflector. But don’t search for this book, because I have the only one.
Another good book for telescope making is Building Your Own Telescope, by Allen Thompson. I have not read it myself but many have said it is a very good reading, and can had for around 10 dollars (here). Look around, you’ll find countless books on this subject, they are not very recent, but still have the same valuable information to build a telescope from the ground up.
So, the question is, which book to buy? This depends on how far you want to go as far as precision for the telescope. I reccomend a simple technique that does not require the foucault test, because it just makes telescope making a whole lot simpler. Plus, a mirror’s figure does not need to be perfect in order to observe celestial objects with satisfactory results. It has been said time and again that a considerably less than perfect mirror will perform as well as a perfected mirror, it is just a matter of conscience.
Before I got really serious about building my telescope, I was demanding for perfection. I had to do the focault test, had to have a parabolic surface, and I wanted at least a 6 inch diameter mirror. It turns out that I did not do/get any of those, and that is fine with me based on what it said in Amateur Telescope Making. Sometime in the near future, I will be putting my grandpa’s book on this website as a page, along with all of the pictures, sketches, and references.
This weekend, I had been pushing some glass myself- only 2 more grades of abraisive left to go! I ground through the 12 micron today, and and hour was enough. Last weekend (and the previous post), I had thought of something that would be simple and effective in cleaning house for the next finer grade of abraisive.
A simple idea really, all I did was cover the top of the grinding stand in clear plastic wrap, then set the tool in place as normal. I tried it, and it really works! Cleanup was easy as ever, all I had to do was simply pull up the tape, and lift the wrap off. Then the new wrap can be laid on and taped, ready for action.
As I am progressing through these finer grades, the glass has started to lighten up a bit, and it is not as frosted as it previously was when I ground the first grade (#80 silicon carbide). I have been told that when the final grade has been finished, the glass should almost be transparent, though not quite, as polishing will remove the final grade of pits.
While progressing through the project, I’ve been planning ahead for gathering the finishing materials (diagonal, diagonal mirror, mirror cell, etc) and found a place to get mirrors aluminized cheap, as well as pretty inexpensive secondary mirrors, and other components.
On Friday morning, I was able to take out my 70mm refractor for a good hour and a half. I was able to get an extraordinary view of the Orion Nebula, which is saying something, because I have seen this diffuse cloud through a 14 inch reflector, so I know what I am talking about. I’d say that the view at 56 power is pretty close to the view through a 6 inch reflector. I hope to have this sketch on Astronomy Sketch of the Day, just like when I had my M31 sketch on there.
Here is my sketch of M42 :
All I can say is, I hope to be sketching this through my 4 inch soon.