grinding thin telescope mirror

Making a telescope mirror. To start, a new mirror blank is "sanded" down to create a precise parabolic curve in a process called grinding. To do that, the blank is paired with a device called ...

The telescope enables our vision quest. A good telescope brings joy and a world beyond words; a good telescope gives crispy images across a range of magnifications and is easy to setup and use. I work on large, very fast, ultra-thin mirrors for 'big aperture, feet on the ground observing' with quick setup lightweight telescope structures.

Showing grinding work on a super-fast 10" F2 telescope mirror. Gordon shows fine grinding by hand using the powered turntable.

Now that I have several blanks made, it is time to grind and polish one into a telescope mirror and test it out. I can use one blank as the mirror and another as the grinding tool, and have a couple in reserve in case something goes horribly wrong during the grinding and polishing operations. I'll post an update once a mirror is completed.

FORCE When grinding thin mirror blanks, be conscious of downward pressure, which if excessive, may bend the mirror blank momentarily out of shape. While this is not a problem during rough grinding (as the amount of flex is exceedingly small) the effect becomes important as you reach the later stages of making your telescope mirror.

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.

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 …

For a discussion on the fabrication of thin mirror blanks please refer to the following article in: Kestner, Bob, "Grinding, Polishing and Figuring Thin Telescope Mirrors, Part 1 - Grinding", Telescope Making 12, Summer 1981, pp.30 -35.

THE AMATEUR TELESCOPE MAKER Conducted by ALB E R T G. IN GAL L S W E ... the mirror, constituted our grinding ma­ ... A piece of thin sheet melal was mounted as a band around part of the mirror's circumference. One end of …

The first phase of rough grinding my 8.5 inch Pyrex disc into a telescope mirror. Including beveling the edges, measuring sagita (central depth), and grindin...

Grinding an 8″ F/10 Telescope Mirror – gordtulloch.com. Grinding an 8″ F/10 Telescope Mirror. For this project (my first time ever grinding a mirror) I ordered an 8″ Black Vitrified Ceramic (BVC) blank without a pregenerated curve from ASM Products in Ste-Basile PQ. Ordering from Canada is always cheaper once you factor in all the taxes ...

A good starter size is the 150 mm (6") mirror. A 200mm (8") will also work. Most ATM books and websites recommend a Pyrex® mirror blank, but in my opinion, annealed plate glass is better for this first, "learn and practice" mirror.It is cheaper, it is softer and grinds faster, needing less abrasives and with these small sizes, the low expansion glass like Pyrex has no practical …

Page 2 of 2 - 24 F/6 thin telescope mirror grinding 3/4 plate - posted in ATM, Optics and DIY Forum: Are there plans/parts list available for this setup?

A 6" or 8" mirror should take about 40 to 80 hours of effort. While this is a non-trivial amount of time, the mirror can be completed in a few months, and certainly within a year. Most people work one to three hours a day on their mirror about one or two times a week. Homemade Mirrors are of Inferior Optical Quality.

The design must also account for back focus distance or the distance from the primary mirror to the focus plane behind the telescope to accommodate the focuser, star diagonal, and eyepiece. Considering the primary mirror focal length, the shortest, or fastest focal ratio generally accomplishable by an advanced ATM is f/4.

The problem with thin mirrors is that they flex more easily during grinding and polishing, making it hard to achieve the required surface precision. They also need a more complex mirror cell (additional support points). Plop is a useful software to let you calculate the number of points needed based on the diameter and thickness of the glass:

10 Inch Mirror Blanks, 3/4" Thick: $55 + S&H (16);Shipping prices are to the USA - not shipping outside the US, sorryCombined shipping is possible - Write. For a complete mirror making KIT, with all abrasives, polishing compounds, pitch, and grinding tool included, please see our Buy Telescope Mirror Kits website for great prices on plate glass ...

Welcome to King Telescopes Not an impressive website. However, we are not in this for a profit. Our intent is to provide a source for lower cost, mirror blanks, and supplies for grinding your own telescope mirror. If I had known as a kid how, well not easy, but indeed not as hard as I would have expected to grind my own mirror.

Any mirror that is less than 6:1 thick is referred to as a thin mirror. Thin mirrors cost slightly less, weigh less, and cool down quicker. But they are much more susceptible to problems with ground in astigmatism and distortion due to support in the telescope unless additional precautions are taken.

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.

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.

The process for grinding telescope mirrors at home actually doesn't look too much different than when Isaac Newton first developed it, and he didn't have any power tools. ... One can cut the Hartmann mask laboriously out of thin card. The ultimate test is the Bath interferometric test, but it's a little complicated.

Making a telescope mirror. ... over the mirror by hand while the mirror rotates on the grinding machine. ... Techno-Fusion mirrors feature an open central structure consisting of two thin glass ...

In this video I am showing you how to make a DIY telescope mirror! This is the second part in the series, showing fine grinding in a step by step tutorial.

Thin Telescope Mirrors . Part 2 - Polishing . Abridged from an article appearing in Telescope Making #13 Provided: Courtesy of Astronomy Magazine Article's Author: Bob Kestner . I am going to start with some additions to topics covered in part 1, on grinding mirrors.

SiC mirror for space telescope is designed as regular polygon rib structures in the rear face for reducing weight, and both the optical face and the backside ribs are so thin that deformation of the mirror cannot disregard. Therefore, in order to feed back deformation of the mirror to the orbit of grinding wheel, it is necessary to analyze ...

Telescope Mirrors, Blanks, Secondaries, Grinding Materials, Testers, Aluminising, Making Advice Information. ... Fused silica between thin blanks supports the mirror and also keeps the weight to a minimum. ... per kilo $40AUD Tin oxide grinding powder per kilo $30AUD Pumice grinding powder per kilo $30AUD 80 Grade grinding powder per 8" mirror ...

spin grinding a slumped mirror - posted in ATM, Optics and DIY Forum: so after taking a few years off from the hobby to get my wife well i have completed my spin grinder and am ready to tackle the 14 honeycombed mirror that you see as my avatar i had it fused to shape many years ago and it is slumped to an F5 curve. i have not used a spin grinder as yet all my …

while grinding. Use a tool sharpening stone, wet it with water, and grind at 45 degrees, around the disc, A 2 mm bevel is enough Making a tile tool "In the old days" it was usual that a mirror kit is delivered with 2 glass blanks. One as the mirror, and the other as the tool.

Telescope Mirror Blanks / There are several advantages to using thin plate glass mirror blanks for grinding your telescope mirror: * Thin mirror blanks are less expensive, allowing more people to afford the hobby of grinding their own telescope mirror * …