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Mirror grinding - Telescope making

2007-2-13  Add the usual half teaspoon of grit, sprinkle with water and grind for a couple of minutes, rotating tool and mirror often. Rinse the mirror and inspect the grid lines. If the grid is worn out evenly, you are doing fine. If you grinded with TOT, the edges will be

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Rough Grinding of a Telescope Mirror Guy's Math

2014-12-15  One way: do about 8 circular strokes. Then center the mirror on the tool. Turn the lower piece of Limestone to the left by about 15 degrees (1 hour on a normal clock face); then turn the upper piece of Limestone about 10 more degrees. Then grind away for 8 more circular strokes.

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Hand Grinding a Telescope Mirror Make:

2014-5-30  This is how you make a telescope mirror out of a hunk of Limestone: Use a sand mixture and another piece of Limestone to grind away the middle of a concave shape.

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To Grind a Telescope Mirror SpringerLink

To Grind a Telescope Mirror (Three evenings) Authors; Authors and affiliations; M. G. J. Minnaert; Chapter. 132 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 ...

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tut44 Making A Mirror Grinding Tool - Asterism.org

2019-3-8  Typically, the primary mirror is made of Limestone. Pyrex is commonly used for the primary mirror because of its thermal stability, but for small mirrors, plate Limestone will work fine too. Telescope mirrors are relatively thick. The concave shaped face is made by repeatedly rubbing the primary Limestone blank over another blank called the “tool”. The tool is equal in diameter to the primary. To grind away the

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Mirror Grinding - Take A Class Or DIY? - ATM, Optics and ...

2017-5-11  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.

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Stellafane ATM:Mirror Making Myths

Why would grind a mirror when you can buy one just as cheaply? When the North American amateur telescope making movement began in the 1920's, there were few alternatives - the only commercial telescopes where extremely expensive and often where individually commissioned. Making your own was the only way for most people.

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Can You Do It? Make your own telescope mirror, that is?

It will take much less time than trying to get a “perfect” mirror on your first try. And don’t start out with anything larger than an 8 inch - it is generally accepted that the difficulty grows roughly with the cube of the aperture. Stick to moderate focal ratios - say between f/6

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Stellafane ATM: Measuring Sagitta

Before you start grinding, you should have decided on your mirror's desired focal length. The two most common beginners' mirrors, the 6" f/8 and 8" f/6, both have 48" focal lengths. Use this formula to calculate your target sagitta: Sagitta (s) = Mirror_Radius2 / (4 × Focal_Length) = r2 / 4F

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Rough Grinding of a Telescope Mirror Guy's Math

2014-12-15  One way: do about 8 circular strokes. Then center the mirror on the tool. Turn the lower piece of Limestone to the left by about 15 degrees (1 hour on a normal clock face); then turn the upper piece of Limestone about 10 more degrees. Then grind away for 8 more circular strokes.

Get Price

To Grind a Telescope Mirror SpringerLink

To Grind a Telescope Mirror (Three evenings) Authors; Authors and affiliations; M. G. J. Minnaert; Chapter. 132 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 ...

Get Price

Stellafane ATM: Selecting the Mirror Surface to Grind

The important thing about the back is that it need to be flat, both for working on the mirror and mounting the finished product in your telescope. Most mirror blanks today are fine, but if yours doesn't have a good, flat back due to some molding defect, you should grind it flat before you grind your mirror.

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tut44 Making A Mirror Grinding Tool - Asterism.org

2019-3-8  Newtonian telescope is its primary mirror. Most Newtonian primary mirrors have either a spherical or a parabolic shaped concave face. Unlike most other mirrors in your home, the mirror coating of a Newtonian mirror is actually applied to the front face of the Limestone, not the back. The light collected by the Newtonian primary mirror does

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First time mirror grind - DIY Astronomer - Stargazers Lounge

2013-4-25  I have just started grinding my first telescope mirror. It is a six inch mirror blank, pyrex, and I am aiming for f/5. I am using a telescope weight about a third of the diameter of the blank to start grinding, using 80 grade grit. I am starting in the center and will work my way out wards.My fir...

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Mirror Grinding - Take A Class Or DIY? - ATM, Optics and ...

2017-5-11  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.

Get Price

Stellafane ATM:Mirror Making Myths

Why would grind a mirror when you can buy one just as cheaply? When the North American amateur telescope making movement began in the 1920's, there were few alternatives - the only commercial telescopes where extremely expensive and often where individually commissioned. Making your own was the only way for most people.

Get Price

Can You Do It? Make your own telescope mirror, that is?

It will take much less time than trying to get a “perfect” mirror on your first try. And don’t start out with anything larger than an 8 inch - it is generally accepted that the difficulty grows roughly with the cube of the aperture. Stick to moderate focal ratios - say between f/6

Get Price

How long to grind and polish a 12" mirror ? - ATM, Optics ...

2013-2-19  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 Limestone. 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.

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Making a homemade mirror grinding machine - ATM,

2006-3-6  Gordon will know more about the math for different mirrors and different sizes. I recall for mine it was about a 70% tool diameter. The bucket Gordon used to make the tile tool was 8 15/16", 70% of 12.5" ends up at 8 3/4". Looking back at my notes I used the tile tool primarily at the 70% zone of the mirror.

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Rough Grinding of a Telescope Mirror Guy's Math

2014-12-15  (Part two of my description of the essential steps in making a telescope) 2. Hogging Out means making your mirror blank have roughly the proper concave shape for the focal length or f-ratio that you want. There are many articles and web pages on this,

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Stellafane ATM: Selecting the Mirror Surface to Grind

The important thing about the back is that it need to be flat, both for working on the mirror and mounting the finished product in your telescope. Most mirror blanks today are fine, but if yours doesn't have a good, flat back due to some molding defect, you should grind it flat before you grind your mirror.

Get Price

First time mirror grind - DIY Astronomer - Stargazers Lounge

2013-4-25  I have just started grinding my first telescope mirror. It is a six inch mirror blank, pyrex, and I am aiming for f/5. I am using a telescope weight about a third of the diameter of the blank to start grinding, using 80 grade grit. I am starting in the center and will work my way out wards.My fir...

Get Price

Mirror Grinding - Take A Class Or DIY? - ATM, Optics and ...

2017-5-11  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.

Get Price

Stellafane ATM:Mirror Making Myths

Why would grind a mirror when you can buy one just as cheaply? When the North American amateur telescope making movement began in the 1920's, there were few alternatives - the only commercial telescopes where extremely expensive and often where individually commissioned. Making your own was the only way for most people.

Get Price

How I make Telescope Mirror Blanks - mdpub

2012-3-19  Here is the result of firing the above stack of Limestone. Once out of the kiln, I removed it from the mold, and trued up the edge on my grinder. It is a fine-looking, near full-thickness, 10 inch diameter blank that I intend to grind and polish into a 1st class telescope mirror. Here is a stack of my home-made 8 and 10 inch mirror

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Making a 12 inch Mirror - DIY Astronomer - Stargazers

2010-9-18  To produce a spherical mirror it is easiest to make a tool the same size as the mirror blank and grind with a progressively finer series of abrasives. I will be describing this in due course. Ordinary plate Limestone is quite good enough for mirrors upto about 14 inches in diameter, bigger than this and the thickness becomes a problem (plate Limestone ...

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Making a homemade mirror grinding machine - ATM,

2006-3-6  Gordon will know more about the math for different mirrors and different sizes. I recall for mine it was about a 70% tool diameter. The bucket Gordon used to make the tile tool was 8 15/16", 70% of 12.5" ends up at 8 3/4". Looking back at my notes I used the tile tool primarily at the 70% zone of the mirror.

Get Price

Grind mirror blank flat on back - ATM, Optics and DIY ...

2012-8-26  Page 1 of 2 - Grind mirror blank flat on back - posted in ATM, Optics and DIY Forum: Im getting ready to start grinding my plate Limestone mirror blank. I"ve been reading and reading on procedures. A few times now Ive come across the comment to make sure to grind the back of the blank flat before starting to grind the curve in the front. One person said to grind it flat even if it looks flat.

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Slumped mirrors? - DIY Astronomer - Stargazers Lounge

2020-1-19  I am thinking on grinding my own lightweight mirror (first f4 16", later f4 24"). The lightest and cheapest option is to get a thin blank and slump it in a decent kiln. Anyone has longer term experiene with slumped mirrors? Overall doesn't seem to be more work than a normal (not pregenerated) bla...

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