Our rough grinding mirror

Mirror blank kit - ATM, Optics and DIY Forum - Cloudy …

2014-06-23· I purchased my 8" mirror making kit from Newport Glass and it included a Pyrex blank, a plate glass tool, all the grits needed from silicon carbide #80 grit for rough grinding through cerium oxide for polishing and figuring.

Newport Glass Works, LTD. Grinding, Polishing and …

Rough Grinding Once you have the back of the mirror ground flat through 220 and the face reasonably flat, you're ready to start roughing the curve into the mirror. I recommend #60 carborundum for rough grinding.

Rough Grinding a 20" Quartz Telescope Mirror on the …

"After hogging the mirror blank to depth, the rough grinding stage begins. In this video I am grinding with grit." In this video I am grinding with grit." "Telescope Mirror Making: Part 2, Hogging to depth - …

Joy of Mirror Making: Rough Grinding - BBAstroDesigns

31 · Mel Bartels Rough Grinding The first milestone is putting a curve into the mirror face. The curve's depth dictates the mirror's focal length. The curve should be spherical.

Rough grinding a 6 inch mirror - ATM, Optics and DIY …

2005-04-20· Rough grinding a 6 inch mirror - posted in ATM, Optics and DIY Forum: I am following Texereaus book. I am rough grinding a 6 inch mirror an went from a chord stroke to a center over center stroke a little late in my rough grinding. I ran out of 80 Carbo and I think my mirror is still a little hyperbolic (although it looks ok against the ...

Casting a Large, Light-Weight Telescope Mirror From ...

Photo #2 shows the mirror at the end of rough grinding. I was aiming for an f/4.5 mirror, so the required depth of the curve is 0.175 inch. Once the required depth is reached, the rough grinding is complete. Amazingly, the rough grinding has removed over a pound of glass. The mirror now weighs in at only only 8 pounds 15 ounces. Now the fine grinding can begin to clean up the rough surface ...

Large Homemade Telescope Making Project - Google Sites

To eliminate the need for rough grinding and save time, I had the mirror kit supplier rough grind the mirror to focal ratio of about F/8 (they also ground the back of the mirror nice and flat). Why such a long focal length? Well, I mainly enjoy looking at the planets and so a long focal length and small secondary mirror are desirable. More importantly, figuring and testing the mirror's surface ...

Notes from John Dobson's Telescope Making Class

Week 2 (rough grinding) October 17. Rough grinding is done to create the curve in the mirror. Fine grinding is used to subsequently smooth the curve.

Rough grinding a mirror blank - YouTube

2011-04-27· Pushing glass. The initial rough grinding of a 10 inch diameter, f/5 telescope mirror blank. See updates on this project at mdpub.com.

Rough Grinding of a Telescope Mirror | Guy's Math & Astro …

(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.

Rough Grinding - chestofbooks.com

In order to hold the mirror comfortably and to avoid touching it with the fingers during fine-grinding, I obtained a disc of hard wood 6 in. in diameter and $ in. thick with a handle 1 1/2 in. thick and 3 1/2 in. long fixed in the center.

Ed Grinds a Mirror -

Introduction: This summer (2000) I joined a mirror-grinding class hosted by our local club's ATM committee. Despite having looked through hundreds of telescopes through my observing career, I had to admit I had never ground my own mirror; in fact, my knowledge of the …

Stellafane ATM: Rough Grinding

This page describes the rough grinding process. Before You Start. Use this checklist to make sure you are ready to start rough grinding: You have selected a mirror diameter and focal ratio, and have use these to calculate a target sagitta.

tut44 Making A Mirror Grinding Tool

Making A Mirror Grinding Tool By Allen Malsburry The average person would never think, "I can make my own telescope." Most amateur astronomers believe, "I can buy a better

Telescope Making Supplies - willbell.com

The cooled mass is then broken up and rough graded by screening. The individual crystals are treated by impact, crushing or air blasting to remove brittle edges. Finally, it is graded by screening, water sedimentation, hydraulic flotation or air classification, with the latter used for the very fine grades.

Making the 20 inch Conical Mirror | Pierre Lemay

After generating the f/3.9 curve using the methods described above, and thinning the edge of the blank to ½ inch, the 32 pound, 20 inch pyrex mirror blank was ready for conventional rough grinding with a full sized tool. Here is what the glass looked like just before conventional grinding:

- WOS - Wenk Observatory Solutions

When delivered, the mirror blank should be square on both sides. In the process of Rough Grinding one side gets the the desired sperical curvature using an abrading medium (silicon carbide) and a very simple grinding …

How I built an edge grinder for telescope mirror blanks.

The rough grinding drum very quickly got the edge trued up and round and to the correct diameter with a minimum of effort and drama. A jet of cooling water was directed at the grinding drum at all times to prevent over-heating the glass and causing chips to spall out of the edge. The water came from a large pump sprayer tank. The spray nozzle was removed to get this photo. I will try to ...

Stellafane ATM: Fine Grinding

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.

Telescope Mirror Making Guide - Rough Grinding

For rough grinding you will work mainly with your grinding tool on the bottom and the mirror on top. Starting out you will concentrate on grinding the center of your mirror since it …

Grinding - Amateur Telescope Making - India - Google Sites

If the mirror is too shallow continue rough grinding (see next section, however); if too deep, invert the mirror and tool and grind with centered 1/3D strokes until the sagitta is reduced to the correct value. Stop off axis grinding.

ROUGH GRINDING THE MIRROR - Sidewalk Astronomers

ROUGH GRINDING THE MIRROR. The heart of the Newtonian telescope is the comparatively long focus, parabolic mirror called the objective. It gathers light from the object and forms an image of the object in the focal plane at the eyepiece.

Build your own telescope part 1: The mirror – Thomas ...

Whether you buy or cast your own blank, it often turns up to have rough sides with marks left from the kiln. The first thing you want to do is to flatten one side (it will become the back) by grinding it against a flat piece of glass (e.g. a old window).

Mirror grinding - Telescope making

There are many reasons for grinding your own mirror. Either you want a unusual size, or focal length, or to satisfy your curiosity, or to have the "pride of achievement" by fabricating something as precise as a telescope mirror.

How I make Telescope Mirror Blanks - mdpub.com

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 blanks. The second from the bottom is the one above.

Rough Grinding a 20" Quartz Telescope Mirror on the Fixed ...

2010-03-07· This video shows how to setup a mirror grinding machine for fixed-post grinding, also known as spin grinding or spinning. After setup, you'll see how abrasive and water are applied, and how the ...

Joy of Mirror Making: Polishing - BBAstroDesigns

The goal of polishing is simple: polish out all the tiny pits that remain from fine grinding, ending with a smooth spherical mirror surface ready to parabolize. You will use a laser pointer to look for any remaining pits and a Ronchi tester to look for a smooth mirror profile.

Mirror-o-Matic mirror making machine - ATM pages of ...

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.

Fine Grinding the Mirror - Sidewalk Astronomers

FINE GRINDING THE MIRROR. After generating the mirror curve by rough grinding it remains for us to smooth it by fine grinding and polishing before finally correcting it to a parabola of revolution.