hand grinding a telescope mirror | make:,this is how you make a telescope mirror out of a hunk of glass: use a sand mixture and another piece of glass to grind away the middle of a concave shape. repeat with finer and finer grit sand. dave barosso demonstrates the technique, but to do it yourself, try to visit one of the telescope makers workshop‘s classes on friday nights in oakland..mold making for slumping mirrors in a kiln,here's the before and after images from a few hours grinding with ring tools. the 42 inch mirror explodes! after regrinding the mold, the previously slumped 42 inch mirror was placed on top for a second slump run. part way through the heating, the mirror exploded with a noise that was heard from the house..telescope mirror grinding machine | crusher mills, cone,fine grinding a 20' quartz telescope mirror. rough grinding on the fixed-post mirror grinding machine. hogging the curve on a 20' f/4.5 quartz telescope mirror..telescope mirror grinding machines | crusher mills, cone,… grind a series of telescope mirrors starting with a 24-inch and then a 60-inch mirror for a telescope initially intended for the yerkes observatory. the grinding machine 50 inch telescope (1.3 meter telescope) at the astronomical.
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the mirrors •two 20” (508mm) pyrex mirror blanks imported from newport glass works. •factory diamond tool pre-ground to f4.5 and fine annealed. •48mm thick – classed as “thin” mirrors. •weight of 20 kg each. •had to be further shaped by grinding, polishing and eventually figured to a good paraboloid..thin telescope mirror grinding advice,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..grind and polish a dobsonian/newtonian telescope mirror,supplies. 2 pieces of glass - one will be the mirror, the other is the tool you will use to grind it. mine were plate glass 6.25' in diameter for the mirror and 5.75' in diameter for the tool, 3/4' thick. you can buy glass blanks online, in addition to other telescope making supplies at first hand discovery..newport glass works, ltd. grinding, polishing and figuring,grinding the back flat is just the first step in preventing astigmatism. the next step is the proper mirror support. fine grind and polish the mirror face up. a thin mirror bends over the edge of the tool if it's worked on top, so the problem reduces to supporting the mirror from its underside.
i know it is bordering on the edge of extremely thin with a 32:1 thickness ratio but it is possible as john dobson has been known to successfully grind a 24' mirror 3/4' thickness. we have decided on an f/6 with a .25' sagitta it allows .5' center thickness..telescope mirror blanks / telescopemirrorblanks.com,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. * choosing a thin mirror blank gets you more aperture for your dollar..mirror grinding - telescope making,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 (visible at.mirror grinding machine,over the years, i'd been collecting motors, gear boxes, pulleys, etc. most of them came from industrial junk yards. to use these parts, i had to modify some of dennis' plans. how i did it is described below. this machine is the result. it is capable of grinding up to 20' telescope mirrors. pictured is a 10'.
a large thin mirror dobsonian can be made for a very reasonable cost and is transportable to dark skies. there is a reason why long lines form behind these scopes at star parties - the views are incredible! gazing at incredibly distant galaxies using a mirror that you have ground yourself is immensely satisfying and joyful. in addition, a great deal of money will be saved: a finished 24' scope will set you back.king telescopes, telescope mirror blanks, using both,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..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. i can use the thinner blank below it as the grinding tool..telescope mirrors, blanks, secondaries, grinding materials,aluminium oxide grinding powder per kilo $40aud tin oxide grinding powder per kilo $30aud pumice grinding powder per kilo $30aud 80 grade grinding powder per 8' mirror $2aud 120 ' ' $2aud 220 ' ' $3aud 320 ' ' $4aud 500 ' ' $6aud 1000 ' ' $8aud 1600 ' '
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. i got in trouble with the moderators here due to being discouraging about a new mirror maker's project, which as i recall was big, thin, and fast..grinding and polishing a meniscus mirror – astronomy,in many respects, the grinding and polishing stages of fabricating a thin meniscus telescope mirror are not different from any telescope mirror. there are lots of resources, online and in print, describing that. this article will focus on the specific issues introduced by working on such a mirror..grinding,polishing and figuring - part 2 - polishing,holding the mirror: don't let your fingers touch the bevel of your glass while rotating the mirror during grinding and polishing. when you rotate the mirror during it closer to the center of the edge. touching the bevel heats the glass, causing to expand..how to make your own telescope mirror - instructables,while fine grinding make sure you don't move to the next grit until your sure you've gotten all the pits of the previous rougher grit removed. after your finished with fine grinding the mirror you will need to make yet another tool. this tool is called a pitch lap.
lightweight composite mirrors, for example, have been verified with surface microroughness as low as 0.7 nm rms--smoother than the primary mirror of the hubble space telescope at 2.5 nm rms. thin, but fit . traditional mirror fabrication--grinding a glass blank to shape and coating it with a reflective surface film--achieves lightweighting by including special low-weight materials, making the substrate.elid grinding of sic ultra lightweight mirror,we fabricated lightweight sic mirrors by using an ultra-precision rotary grinder “rg-800” with rotary table of 800mm in diameter and 10 nm precision in control resolution ( fig. 3, 4 ). the grinding of the mirror by rg-800 is executed by tracing the grinding wheel from the outer to the center of the work piece..making mirrors for giant telescopes - spie digital library,a key aspect of the concept is that schott and corning developed the ability to make these thin 8 m mirrors, not without some struggles in the process. similar mirrors are used as the 3.4 m secondary mirror of the large synoptic survey telescope (lsst) and the 4.stellafane atm: grits, polish & pitch,some amateurs prefer to use a minimum of grit sizes (minimizes cleanup between grits time and cost of supplies). mel bartels, a well respected west coast amateur, recommends on his large, thin mirror grinding web page starting with something between 30 and 60 grit, and then 120, 220, 500 (=25 micron) and finishing with 9 micron. this is just a 5 grit sequence, as opposed to 8 to 10 for the more
commercial manufacturers usually use computer-controlled grinding machines to standardize their production runs. amateur mirror-makers grind their mirrors by hand, testing the figure  every so often. very high end telescope mirrors might be hand made, or.mirror grinding kits - lafermeacolette.fr,telescope mirror kits firsthand discovery. 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 if you need materials for making a.fabrication of large secondary mirrors for astronomical,3. optical process --step 2, grind the mirror spherical we start work on the optical surface by grinding it to the best-fitting spherical surface. this is done for several reasons. first, it is easy to achieve a good sphere using a large rigid tile-faced tool. large grits and long running times can be used.tut44 making a mirror grinding tool - asterism.org,of the mirror blank using the tool you just finished: http://stellafane.org/tm/atm/grind/rough.html they have short videos for each of the two different strokes you will need to compete grinding your mirror: http://stellafane.org/tm/atm/mirror-refs/strokes.html#the chordal stroke the site contains many other suggestions you should consider
grinding a telescope mirror: the non-diy project. posted on march 4, 2017 by telescope paul. john dobson. i did not know john dobson, nor do i know someone who knew him, but i feel like i did from all the testimonials i have read. at the least, my telescope build is.mirror grinding kit grind and polish telescope mirror at,all our mirror kits contain a pilkington float glass mirror blank and grinding tool. these arefinished with fine ground edges. 180 grade first stage ginding powder. 400 grade ginding powder. 303 grade smoothing powder. top quality cerium oxide polishing powder..telescope mirror grinding machine | products & suppliers,the process was performed at cranfield university precision engineering on the box grinding machine (figure 4, left), designed for rapid and accurate grinding of large telescope mirror segments . fast figuring of large optics by reactive atom plasma