More about Mirror Making

The project is going very well, I am not posting as much as usual, I started school on Monday, and Wednesday is my best day to do this sort of thing.  The 80 pound grinding was rolled into the garage, then it was leveled.  The next step was to bring a table so that all of the supplies could be in one place.

For the instructions, I called my grandpa, he has built 3 to 12 inches telescopes in the past.  I had little wooden cleats cut to hold the tool in place.  Also for instructions, I used Amateur Telescope Making and Building a Reflecting Telescope, which was written by my grandpa in college.

To start off, I sprinkled on the tool 1/4 teaspoon of #80 silicon carbide on the tool, then 1/4 teaspoon of water and spread it all around.  The next thing to do is place the second disk on the tool and push the mirror firmly away from you, as far as it will go, then do the same, bringing it back.  Make sure to time the whole process.  For the 4 inch mirror, 30 minutes should be good or around there.

When you slide the mirror off the tool and rinse it with water, it should look rough and frosted, which is exactly what it is.  To check the focal length, I took it out in the sun, and wet the mirror.  The next thing is to reflect the sun’s image onto a wall or something flat.  Move the mirror to and fro the wall, keeping it wet, until the smallest image is obtained.  I then measured the distance between the glass the wall, to determine the focal length.  The whole process is very intriguing and it is lot’s of fun too.

I ground all the way to the second abrasive, #120, finished that and went back the next day to do the #220.  After 30 minutes of grinding with it, the surface smoothed enough to reveal some pits, which I removed.  Another great idea I had was to set up a grinding log to show all of my progress.  2 days have already filled practically the entire page.


       The night before I started, I had one of the best observing nights in my life.  The seeing was a 6 out of 10 and there were scattered clouds throughout the sky.  Me and my dad were outside using the XX14g.  At the time, it was 85 degrees, at 11:00 at night.  I thought about making a sketch of the M57, which was at the zenith at the time.  Upon studying it, I always detect a little green-blue color in it.  But this was different: the center star was seen in the moments of good seeing.  Instant chills went throughout my entire body as I glimpsed that single star.  I’ll never forget that one moment.

At the beginning of the night, we were setting up everything up, and we had the big floodlight on to see what we were doing.  Just before it turned off I took this picture of the scope, you should click on it to see the big version.  Anyway, I am hoping to finish the mirror project by the end of October.  My dream telescope that might be within reach is Orion’s 10 inch Classic dob.  I’ve heard lot’s of good things about them and maybe I can own one someday.

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2 thoughts on “More about Mirror Making

  1. HI JUSTIN;
    YOUR GRANDMOTHER AND I WERE SURPRISED AT HOW MUCH YOU HAVE GROWN SINCE
    WE LAST SAW YOU…. THE PHOTO OF YOU LOOKS GREAT, YOU LOOK LIKE A REAL PRO.
    KEEP UP THE GOOD WORK AND WILL BE IN TOUCH.
    LOVE AND REGARDS
    GRANDMA & PA

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