Mirror makers turn to sub-diameter laps for larger faster mirrors. Deep parabolas can be carved out and zonal irregularities attacked. However, surface smoothness is an issue. A smooth mirror surface along with deep parabolas can be achieved with full-sized or over-sized pitch laps by varying the pitch lap's area of contact.

• Grinding ±0.008mm • Lapping ±0.005mm Surface finish, roughness Casting • Die Casting Good 1-2µm • Investment Good 1.5-3 • Sand Casting Poor 12-25 Metal forming • Cold rolling Good 1-3 • Hot rolling Poor 12-25 Machining • Boring Good 0.5-6 • Drilling Medium 1.5-6 • Milling Good 1-6 • Turning Good 0.5-6

I'm talking multiple primaries, not folded scopes. I KNOW that mirror focal lengths must be matched, and there are BIG collimation headaches, and that mirrors off axis have coma probs (Long focal length may not be so bad), but I can get 4 or 5 finished 6" mirrors for less than a 12" mirror grinding kit.

Grinding time per mirror was 5 hrs of 500 grit, 5 hrs of 220 grit and 4 hours of 60-90 grit; grinding times for the tool are double the individual mirror numbers. Step #10: cast a new tiled tool to finish grinding. Goal: make a replacement tool …

Could anybody recommend a book on mirror grinding and figuring that is easy to buy in the UK and easy to follow. I'm after a default recommended text just like Making Every Photon Count is the recommended text for AP. ... you should do a nice 12" f6.

SVBONY 1.25 inches 90 Degree Zenith Diagonal Mirror for Refractor and Cassegrain Telpes Astronomical Telpe. 4.3 out of 5 stars. 189. $18.99. $18. . 99. Get it as soon as Thu, Nov 4. FREE Shipping on orders over $25 shipped by Amazon.

Metal bonded diamond grinding wheels are very important for precision grinding operations of hard and brittle materials especially like ceramics or cemented carbides. But the trueing and dressing problem has affected its wide use. In this paper, a new EDD (Electrical discharge dressing) device was developed for the dressing of metal bonded diamond arc grinding …

Grinding aspherical elements is very difficult if you don't want to leave extremely ugly circular marks that end up showing in the oof highlights. Those are the reasons why I sold the first 3 Otus. The 100mm f1.4 is mostly free of them and so is the Nikon 58mm f0.95 Noct. Another example of a lens ruined by those marks is the Canon 28-70mm f2.0.

Nikon announces new budget Z 28-75mm F2.8 and teases 800mm F6.3 PF Nikon has announced the Z 28-75mm F2.8, a new standard zoom lens for its full-frame Z-mount cameras, billed as a more affordable alternative to the Z 24-70mm F2.8 S. Alongside the new zoom, Nikon is also teasing the development of a super tele 800mm F6.3 prime.

Rough grinding. This step is about making one side of the glass concave. It will give your mirror its overall focal ratio. If you make the centre deep, you will end up with a fast telpe (e.g. F/D = 4) well suited for deep sky observations. On the opposite, a shallow mirror (e.g. F/D = 8) will be performing very well on planets and the moon.

Mirror Grinding at the Spring 1998 Stellafane Mirror Workshop in the McGregor Observatory Rough Grinding. The purpose of rough grinding is to start to cut a spherical concave surface into the mirror blank. For a 6" mirror with a 48" focal length, the depth of the curve is 0.047". A full sized tool is rubbed against the mirror blank, with a wet ...

Finally got to the fine grinding stage for my 8" F6 telpe mirror! by [deleted] in telpes. Natoface 1 point 2 points 3 points 2 years ago . awesome, have you made telpes before? I've wanted to make one but it looks like a massive effort and I wouldnt know where to alluminise maybe spelling the reflector. permalink ...

Telpe mirror grinding machine Mirror making and optical testing … The images below show the completed grinding machine in it's new garage in October 2001. GrindingPolishingMachine – LCAO. Telpe Making. Telpe Mirror Grinding and Polishing Machine. After I had made the 41-cm telpe mirror by hand I had decided that I needed a ...

Making a telpe 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 …

12.5" Plate glass mirror rough ground too deep - posted in ATM, Optics and DIY Forum: Hi, Just looking for a little advise. I have been rough grinding a 12.5 x 1.5 thick plate glass mirror. I was originally aiming for F6 because this is only the second mirror I have ever attempted and I didnt want to figure anything too fast. Unfortunately, I ground it too deep and it …

The 1.3m telpe mirror blank has been completed by Peter Wangsness and is now … 1.3m mirror blank – yard stick comparison . 1.3-m Mirror Grinding Machine – Photo: Mike … Mirror-o-Matic mirror making machine – ATM pages of Berthold …

I applied some Dykem layout dye to the outer 1/2" of the mirror and a couple of bands across the mirror. After the first 30min most of the Dykem was gone but you can still see an area on the outer 1/4" with some blue specks. There are still a couple of pits but the dykem was all gone after the hour of grinding. Total of 2 hrs at 120grit so far.

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

Making a 250mm f6.4 parabolic mirror. 1: Preparations. First things first: this section lists some initial things to do, such as purchase the raw materials and cut out a glass disk. ... I think in the meanwhile i will try to make a set of 1:10 pulleys for a V-belt. I've also started constuction of a grinding bench. The top surface is a circular ...

8" F6 Mirror Grinding For grinding tools I have read that it is recommended to use dental plaster or pure cement as a substrate. Then tiles are attached to this substrate either by glue or to embed them directly in the plaster or cement when the cast is made. Other tools used for hogging out also can be a metal ring or pipe flange.

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 " " $8AUD Cerium Oxide " $8AUD Lap resin kit " $15AUD

But this record-shattering international growth came to a grinding halt in 2018 when Kentucky distillers became pawns in a much higher stakes game: Trade wars… In 2018, the United States imposed tariffs on steel and aluminum. In response, the EU and Mexico slapped 25% tariffs on American whiskey, which predominantly affects Kentucky Bourbon.

A few years ago, I was thinking about hand grinding a mirror. I watched a YouTube video of John Dobson hand grinding a mirror. I don't really remember how big it was, but it was big. Maybe 14". Maybe larger. John was no youngster in this video and even though he is a master, he sure put a hellova lot of labor into that mirror.

Grinding time per mirror was 5 hrs of 500 grit, 5 hrs of 220 grit and 4 hours of 60-90 grit; grinding times for the tool are double the individual mirror numbers. Step #10: cast a new tiled tool to finish grinding. Goal: make a replacement tool …

Page 1 of 3 - Mirror Grinding - Take A Class Or DIY? - posted in ATM, Optics and DIY Forum: Ive been interested in grinding/polishing my own Newt mirror for a long time but dont know how to get started. As a beginner, would you recommend attending a workshop or class or is it possible to make a good mirror using other learning resources such as books …

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The first design was a 150 mm F4 Newtonian (diameter of the main mirror 150 mm with the F-ratio 4). However, I was told that a F4 mirror is not very easy to make especially if you are grinding your first one. Therefore I decided to make a F6 mirror instead of F4.

8" Newport Mirror grinding kit 8" Newport pyrex mirror grinding kit Includes: - machine ground pyrex blank for f6 - grinding materials - grinding tool - 1/10 secondary mirror: Price: $150 Posted on: 16:36:43 Last Updated on: 16:37:29 Contact: florin (user details & view my other ads) Phone Number (optional): Not provided

Click for price. Sometimes the reason that you are looking for a mirror alternative will be due to a lack of space. If you don't have the room to hang a mirror in your bathroom or your bedroom, then maybe you should think about purchasing a door mirror. A door mirror will be able to provide you with the mirror that you need, while not getting in your way.

[ATM] 20incher with segmented and ribbed mirror at 12Kg, Andreas Derwahl. Re: [ATM] 20incher with segmented and ribbed mirror at 12Kg, Ric Rokosz. Re: [ATM] 20incher with segmented and ribbed mirror at 12Kg, Andreas Derwahl. Re: [ATM] 20incher with segmented and ribbed mirror at 12Kg, John Sherman; Re: [ATM] 20incher with segmented and ribbed mirror at 12Kg, Mel …