KZfaq: I see you like CNC machining and restoration videos, here's a mirror resurfacing video. Me: ok... I guess that'll do..

I like the slight hesitation at "A little bit of effort to grind it out" I interpret that as "This'll be a bitch!"

I always enjoy watching Gordon’s videos. Been watching for years now. Hope your doing well Gordon. Thanks for these great learning lessons in grinding mirrors.

Dear lord I hope you purchased a wider-tipped Sharpee since making this video...

Yes, this was recommended to me too

Gordon, Thank you so much for sharing your expertise with us. It would be nice to know how the project turned out and if your customer has completed his/her scope.

Great stuff! I love seeing big light buckets being made, especially if they will be accessible by the public, as I think Time/Life/Nat. Geo astronomical photos tend to set up the public for a bit of disappointment when they go to a star party or open house and find that they cannot see similar visions live, through a scope , with their eyeball. Big scopes can help, but few are accessible to the public. When I was a kid, i was privileged to become a keyholder (the youngest, up to that point, I think) to both observatories of the Peoria Astronomical Society in Illinois, which included access to both a 20" and 14". The 20" was amateur-built yet of greater optical quality than many scientific instruments in private and government hands. There's nothing quite like the PAS in Colorado, and I do miss it. Am moving to mountains in a few years, and I'm already planning to get back into telescope making then

I would love to see a mirror done from start to finish. Opening the blank to packaging for shipment. I'm particularly interested in the final steps.

I am a disabled veteran so I know I will never have the opportunity to own such a magnificent piece of equipment. However, it is on my bucket list to be allowed the honor to look through one in my life. I have a Celestron Nextstar 8ES but I have not been out observing in years, my back cannot handle the weight of transporting and setting up my scope. I have always wanted to gaze upon the horsehead nebula, for me, it is the holy grail if astronomical observation. I bet with the light gathering capability of the 22 or 25-inch scope you can see it pretty easily.

Great, another channel I have to subscribe to because its awesome.

There was a day and time when, especially being originally ground with a diamond bit that there would not have been all of those 2nd if not 3rd grade defects in a purchased item UNLESS one paid less for it due to the 3rd grade defects in the piece! BUT great work on your part, for both the work done and the instruction on the what’s how’s and why’s!!!

Gordon, I've recently been bitten by the telescope bug and I automate for a living. I've been watching videos about making mirrors and I can't help but wonder what technology has been applied to this. I see the defect on the glass in this video. If the table had an encoder suitable for position control, and a tool to measure the flaw from center to edge, the flaw could be mapped out on the entire mirror. A laser for etching glass could be used to remove the prescribed amount of glass necessary to correct the flaw. If the measuring device is also a laser, the process could be quick and accurate. The laser doing the measuring could monitor the results of the corrections as they happen. The etcher could be on one side of the mirror and the measuring laser could be on the other side. As the mirror is spinning, the etched spots would be checked by the measuring laser after perhaps another half turn. The finish would be poor and there might be subsurface fractures, but the surface would be close to true. Maybe there would be less grinding to do afterwards. I work with PLCs (Programmable Logic Controllers) and to some degree with robots. There are probably a few robots in scrap heaps that work just fine. I think that if the above philosophy were applied to a robot, the process could be done with little supervision. It would be a dream to have a little shop with some cool machines that spit out a lot of high quality mirrors. I figure that if I have thought about this in the last month or so, probably a lot of other people have beat me to it. Do you know if anyone has designed machines for this? Is there a huge gap in technology between amateur and commercial? I very much enjoy your videos, thanks!

thanks for sharing your knowledge on the web for free

That's really cool!

wow .its damn cool i cant even imagine where to start but i love stars. gratz from canada lac st jean

Newport glass is really sketchy the secretary never got back to me after he said he would so I just got off united lens btw great video!

That's awesome, greetings

Not sure if this message is helpful but they make powder guidecoat. You can probably find it in an automotive parts place. I hated using it with bodywork because it got a little messy when I was in a hurry. But it helped with my bondo. Thanks for the video. I am looking forward to making my own mirror.

Have you ever tried Dykem? It's a marking fluid used by machinists. It's effectively sharpie, but you can apply it with a brush very evenly and quickly.

Hi other people that this got recommended to

In the early 1970’s I Hand Ground a 10 Inch Mirror. It took Me forever. If I’d had this machine I would doubtless have been grinding larger mirrors too.

I don’t know what I’m watching but I like it

Спасибо за ваш труд я тоже занимаюсь этим увлечением желаю вам здоровья и терпеия .Thank you for your Work i am also engaged inthis hobby i wish you health and patience.

I noticed the grinding stone was passively driven by friction with the glass. I wonder if the is any variation in speed and whether it makes a difference.

Então a borda da ferramenta deve sempre ficar no centro do espelho? A tradução do KZfaq não foi muito clara para mim.

Looks like fun. Y'know,Jjohn Dobson used to tell us that he made his first 24 - incher from a surplus port- hole glass ( his standard material in the old days ) that he and a friend sawed in half ( thickness ) with a HANDSAW ! , after they mounted the thing in a wood frame. Good Ole' ... J. D. Gone but never forgotten. Cheers !

So how exactly does that grinder wheel lead to the desired curvature?

How long can it take to manufacture a mirror like this with this same machinery?

where you got that glass cylinder from what you grind a mirror ??

Quick optical trick when the glass is spinning watch it carefully the entire time all the way up to the 4 min mark. So watch him mark it up with the sharpie and keep watching until it stops. As soon as he stops it at 4 mins scroll down and look at any text in the comments. Not sure how this will work on a phone or tablet, but on a larger computer screen the effect is kinda fun.

Just out of curiosity do you ever recondition mirrors???

Greetings from Brazil

do you correct these, or are they for viewing only?

Would it not make sense to use 'Dykem' engineering layout fluid or something similar?

Hi gordon.. I am looking for optical mirror for making telescope.. Do you know where do i get this..

Ok KZfaq I watch the damn video! Happy now?

Didn’t know Cody’sLab had a third channel where he grinds mirrors. Cool!

Hola Gordon. estoy haciendo un espejo de 14 pulgadas con una herramienta de 11 pulgadas. cuánto tiempo que sobresalir la herramienta del espejo para que salga esférico el espejo?

Way better than the knees and bench work

I'm making a cassergrain/reflector dual just like the takahashi cn212

Is that a some sort of special glass blank manufactured using a cast or just plain thick glass blank( float glass)?

Hmm how will you get a spherical grind with this grinding setup? I can is the tool exactly 90 degree to the glass or are you using a spherical tool? But if so the high spot in the middle of the tool will only grind on one circle on the glass in this setup

Do you use a fixed post machine for all your work? I am re-watching all your videos.

I guess grinding is where the precision comes in, but my first thought would have been, “Can I get my money back?” (Not having any experience with mirror stock or grinding.)

How do you determine the f rating? In glass, its the purity of the glass, yes?

If u pause it The disc turns backwards

I do have one question, why do you have to spend so much to make mirrors by melting glasses and moulding it, taking care in grinding to the exact point required. Wherein you can get it done in a metal place with mirror finish coating and use it the same way as glass mirror..my question may not be that exact but this is just my thought...

So how did your 22" binos come out? Any pictures of it? Maybe KZfaq videos? I built a 20" f4.5 binocular scope that was featured in Sky and Telescope back in 1993 (I believe) It was an amazing scope(s) the problem too was that if I was going to spend as much as I did on the scope I of course had to have the best eyepieces. So that meant 2-35mm Panoptics, 2-16mm Naglers and so on! Eee$$$kk! I think at f-4 you're gonna have issues with getting the stars to merge without knocking the scope out of colimation. Had a lot of interesting adventures with that scope before I sold it. :-)

Although this is an awesome video I must say something here and I truly hope that I strike a nerve but at the same time I do not offend anyone by doing it. So here it is: There are tens of videos on how to grind your own telescope mirror and they are all awesome made by awesome people who get to do this. My problem is with the videos that are missing from the online medium and those are the videos where someone actually uses these DIY/homemade mirrors and actually shows us some sky photos taken with them. Hope I am wrong here but there's my 5 cents n the matter.

a 10in version of the takahashi cn212 i need to make a 2in hole in it

Out of curiosity - what's the ballpark cost for a blank of this size?

do you need to find the center of the mirror before drilling a hole in it??

What does f/4 mean?....can anybody explain please?

is the mirror actually spherical or parabolic?

So where is video 2

##besten#Liebe##Episode

Amazing! One lens like this one in video costs? 3000USD?

That defect looks like the diamond tool kept spinning while the lens stood still.

For someone like me: It's aperture is about 550mm and focal length about 2200mm

If the grinding stone is just sitting on the mirror, then theoretically it wouldn't make a complete even finish since the contact point of the two changes. No reference hight.

how much is a blank like that cost

You need a bigger marker

Why not use Dykem?

5:50 where the grinding starts

who cast the blank? i assume no centrifuge was used or that was a botch job

hi there. How did you calculate 176 inches focal length with f-4 and 22 inch diameter mirror? Wouldn't it be for 44 inch mirror? Or is it because you are making binocular? I didnt think it made difference, thanks!

i was whatching dragonball z clips and now im here. ok. i guess.

maybe I am slow, but that looks like a lens to me. not a mirror.

2:49 Aaand SOLD! at Southeby's for $ 485.000

Какой большой кусочек колбаски....

Must be a nightmare to do it right, a lot can go wrong.....

Why is this in my recommended videos? xd

That looks expensive

i dont even have a telescope, wtf am i doing watching the entire video ·_·

Who else the thumbnail was a big piece of processed meat

aw crap... 11:23 minutes of getting excited to be left drolling..... come on, put on the entire work video.