Start with one of our telescope mirror kits. Each kit comes with a telescope mirror blank and all the abrasives (silicon carbide grits and white aluminum oxide powders), cerium oxide polish and pitch to grind and polish it to your specifications. Please note that our kits do not include a grinding tool or pitch lap.
A mirror mount is needed to hold the mirror during testing. If the mirror is a 'thin' mirror (i.e. the thickness is much less than 1/8th its diameter) then the mount must hold the mirror without deforming it. The weight of the glass can deform a thin mirror. In my case, I was making a full-thickness mirror, which is a mirror whose thickness is 1/8th the diameter or more, so mirror …
Obtain the right glass. Choose solid grinding tools. Choose the best position to work on mirrors by hand. Grind the back flat. Try and prevent astigmatism. After having the ground and face of the mirror flat through the 220, you are good to begin rough grinding the curve into the mirror. Do some fine grinding.
Gordon Waite shows some steps during fine grinding of the 20" mirror. As the grind progresses through the grades of abrasives, see the technique Gordon uses...
Welcome to my channel - in this video, we will begin to make a telescope mirror from scratch! I'll be showing you the basics of telescope mirror grinding!Her...
How long to grind and polish a 12 mirror ? - posted in ATM, Optics and DIY Forum: Hello everyone ....I have a 12 precurved mirror blank. Its an f/5 made of 1.25 thick plate glass. I also have a matching dental plaster tool with tiles on it. The tool is a bit thick and weighs close to 5 lbs. Its a subdiameter tool thats almost 10 inches in diameter.
Second there are two primary ways of building a telescope. One is to make your own optics, which requires grinding your own primary mirror, the other is buying pre-made mirrors and building a telescope around them. The former will teach you everything you wanted to know about optic design, fabrication, and testing.
Page 1 of 2 - Grinding your own mirror - How is it possible to get accuracy in the nm? - posted in ATM, Optics and DIY Forum: So I have read forum questions & answers on topics such as whether it is possible to use a 3D printer to design and print out a telescope mirror, or design an array of paraboloids this way for a segmented design, and the answers have been, …
Folding Mirrors. The Webb Telescope team also decided to build the mirror in segments on a structure which folds up, like the leaves of a drop-leaf table, so that it can fit into a rocket.The mirror would then unfold after launch. Each of the 18 hexagonal-shaped mirror segments is 1.32 meters (4.3 feet) in diameter, flat to flat.
How to grind a mirror blank into the well-figured basis for a Dobsonian telescope. How to grind the glass, how to carry out a focus test, how to polish with ...
Telescope mirrors are relatively thick. The concave shaped face is made by repeatedly rubbing the primary glass blank over another blank called the "tool". The tool is equal in diameter to the primary. To grind away the ... After fine grinding is complete, the mirror must be polished. It is
Read Jean Texereau, How to Make a Telescope, even if you do find a good mentor to work with. It's a classic, very well written and the methods he describes are still spot on, in year 2020. I would recommend NOT starting with a thin mirror, a really big mirror, or a really fast mirror. An 8 inch f/6 or even 6 inch f/8 is a great starting point.
Mirror-O-Matic grinding machine. When I decided in 2009 after a ten-year break to get into mirror making again, it quickly became clear to me that I would need to construct machine, as hand grinding big mirrors is not something very beneficial for the hands of a musician.
There are a lot of misconceptions about making a mirror - read this even if you don't plan to make a mirror, but just want to know how it is done - with your bare hands and a few simple tools, you can grind and figure a fine mirror with a surface accurate to a few millionths of an inch! Telescope Formulas and Design Comparator
It would be best if you began by sprinkling the abrasive on the mirror face to make it wet. Avoid being too abrasive. Then place your tool down with the edge first and start grinding. Ensure you are rotating the device by walking around the barrel.
For large thin mirrors, say 12 inches [30cm] or greater and 1.5 inches [4cm] or thinner, the mirror back must be ground flat, or at least regular in shape before beginning fine grinding the mirror's face. Cast a tool specifically for the mirror's back, and grind with 220 grit, inspecting for low unground spots. Grind until they disappear.
To Grind a Telescope Mirror (Three evenings) Authors; Authors and affiliations; M. G. J. Minnaert; Chapter. 134 Downloads; Abstract. This exercise is not intended to make a perfect piece of optics, but just to show the principle of the methods used in practice and to convince our students that amateur telescope making is surprisingly simple and ...
Answer (1 of 6): A good friend of mine, and a member of our astronomy club, has ground and polished TWO 32″ diameter mirrors! Yikes! The first one he made was damaged by the coating company, and so he set about making a second mirror! I have looked through both of them, and the images are just st...
I would also read The Dobsonian Telescope by David Kriege and Richard Berry. The construction is a bit dated now, but a good introduction to what is involved in making a telescope for larger mirrors like 18". Also look at the section in the back of that book on grinding and figuring large mirrors by Robert Kestner.
The first thing I built was an extension that sits in the middle of the turntable to raise the working surface above the height of the dam. It was made from an 18 inch diameter tabletop and some scrap lumber. I drew concentric circles on the top of the tabletop in the sizes of common telescope mirror blank diameters.
Please see the Buy Telescope Mirror Blanks page for low prices on plate glass mirror blanks. If you'd like to buy a complete mirror grinding KIT, with all abrasives and grinding tool included, please see the Buy Telescope Mirror Kits. website for the lowest prices on plate glass telescope mirror grinding kits.
Depth to grind the center of the mirror to is found from: mirror diameter * mirror diameter / (16 * focal length). The depth is called the sagitta, and here is the depth to grind for f/5 mirrors: Mirror Dia - Sagitta (inches) 16 0.2 18 0.225 20 0.25 22 0.275 24 0.3 26 0.325 28 0.35 30 0.375 32 0.4 34 0.425 36 0.45 38 0.475 40 0.5
Share. Posted August 24, 2012. The natural mirror grinding process will create a sphere. The first part of making a mirror is to grind and polish to a sphere of the required focal length. Then the mirror is parabolised, by using special polishing strokes, that changes the figure from sphere to paraboloid.
Just input the Sagitta (depth of curve) and Mirror Diameter, and this page will calculate the Focal Length, Focal Ratio and Radius of Curvature. If you want to calculate many other telescope and mirror parameters, use our Telescope Formulas and Design Comparator page.
How to Make Your Own Telescope Mirror: [Fig 1] This is a large piece of glass a woman off Craigslist gave me. It was 40"x40" and 0.75" thick. Its what I decided to use to make the mirror. Cutting it into smaller sections can be difficult but scoring it with a glass cutter …
Altogether, the completed telescope probably costed about $130 for the parts and mirror aluminizing. A fellow amateur astronomer, observing that I had cobbled together the telescope's body parts and brought them to life, started calling my rig "The FrankenScope." Regardless of the name, I am happy with it.
Nov 22, 2015 - Gordon started with a 2" thick telescope mirror that weighed about 70 pounds. By thinning the blank, he's lightened the mirror by about 20 pounds! This vid...
in the 2001-02 Stellafane Mirror Class. Fine grinding refines the basic shape you have ground into the surface of the glass with rough grinding. The sequence of ever finer grits that you use smoothes the rough surface that was made in rough grinding, and prepares you for polishing. You are also refining the shape of the surface to be a section ...
The method is basically to cover the mirror in a light coat of lubricant of some kind (I used vegetable oil) then some saranwrap (cling wrap), then put a "dam" around the mirror to contain the poured plaster – see the above link for more info.
task. Simple test methods are described so that you do not over grind the mirror but achieve the correct shape. How to simply mount the mirror in a tube is then covered in detail. The result will be a working astronomical telescope capable of viewing the Heavens. Only everyday tools are required throughout"--P. [4 of cover].
Grinding the secondary is just like grinding any other optic except in minature. I ground the secondary with the workstand and worked the tool on top just like I would grind a larger mirror. This optic is small enough that a lens grinding machine could work well.
Thin Telescope Mirrors . Abridged from an article appearing in Telescope Making #12 Provided: Courtesy of Astronomy Magazine Article's Author: Bob Kestner . Part I - Grinding . For many years, amateur astronomers and telescope makers thought it essential that glass for telescope primary mirrors be at least one-sixth as thick as its diameter.
My Mirror Grinding Machine. For a long time I've wanted to build a machine for grinding telescope mirrors. Dennis Rech's M-o-M designs finally inspired me to just get up and do it. Over the years, I'd been collecting motors, gear boxes, pulleys, etc. …
The process of making a RC is the same as making a classical. Cassegrain. Jean Texereau explains how to do that in his book on telescope making. Granted the figures are different. but the process is the same.The same methods of testing and. figuring are the same it's that the RC has stronger curves.