In April 1974 my wife and I decided to tour the deserts of the southwest. We saw the Mojave, the Sonora, Joshua Tree and finished with Death Valley. It was one of the best wild flower displays in a century. In Death Valley, we drove up to Dante's View, an elevation on the east side of the valley with a view of the entire valley and across to the Sierras to the west. The parking lot was full of vans, home-made telescopes and people just lazing around. A polite, very tanned man in shorts invited us to return that evening to see the stars. We spent the remainder of the day touring the valley, but did return at dusk to meet John Dobson and the Sidewalk Astronomers of San Francisco. We spent the entire night viewing the heavens as I had never seen them, and I got my first look at the Magellanic Clouds. John said, "Why spend tens of thousands of dollars on a telescope you cannot move? Build your own and buy a van to transport it wherever you want." My interest in astronomy has never waned since that night and I now have two grandchildren to pass this wonder on to. Thank you John.
@@BeardyBaldyBob perhaps he was being a little sloppy with his language and he just meant the milky way. LMC/SMC cant be seen north of about the 20th parallel. I like his story, but I had the same reaction :)
Yes, J. D. was a driven man. I forgot to ask him if, since he was born of missionary parents in China, his parents used to talk to him about finding his " mission ". That's what John had -- a mission. Don't forget he spent 21 years as a monk in theVedanta Society monastery ( the" Monstery" , he called it ). Only when he got ejected did the Sidewalk Astronomers begin. I met him in 1976 at age 22 at Bush St. John knew the trails on Mt. Tamalpais upside and backward. He knew the names ofall the flowers and plants. We used to hike along the old railroad grade and hunt for half - buried spikes. And what an aggressive driver ! He'd sit behind the wheel in consternation at some other driver's indecision and say, in his sing - songway ..." May I inquire, what are your Plans ?" I went on three summer tours in the 80s, then moved into Baker St. Him in thebasement ( loved to watch Quincy M.D. ) and me up near the attic. J.D. taught me how to cook, and boil a chicken. He usedliquid lecithin to make us fried eggs. " Look at 'em slide !, Mr. Doug " Then we'd have a home- made "Green Drink" withRomaine and peanut butter. And man, did he love to give a talk ! Or sing some song he'd dug up from Orpheus, of all people,on his weirdly tuned guitar....Loved to teach us to chant the hymns of Shankara.....But the funniest thing about J.D. was theway he'd just " melt " in the presence of some Big - time Swami from India. When he went there the customs officials wouldn't let the telescopes out of quarantine !! So he had to give slide shows. Just about the best compliment I ever gotwas when John called me a " Hard - core " Sidewalk Astronomer. One more little antic - dote : When we were at Rocky Mtn.State Park , he got madder than usual at the smokers , and suggested to me they should be made to EAT their cigarette butts.I knew my man, so the next morning I was up at sunrise and picked up all the butts ! A little later J.D. came bursting out ofthe motor home with a small paper bag in his hand. " Wha -- wha happened to all the ..... ? " then he caught my eye and we hada chuckle. Well, that was FUN. John Dobson was like a Father to me.
Thank you for sharing this long post! May i quote you? Im writing a little page about telescopes including the huge ex-soviet optical/radio scope in Argatz which hopefully will get repaired.
What an amazing video. Rarely does a video catch my attention for an hour and a half without me noticing time go by. Thanks Mr. Dob for the gift you gave to humanity.
I was fortunate enough back in the 80s to take John's telescope making class. Built one with a hand-ground 12 inch mirror. You could see the rings around Saturn through it!! OK, so it was NOT like a fancy photo from Astonomy magazine, it looked more like a large white dot with a string circling around it, but dang it, it WAS Saturn! How I miss John. My heart still aches over his passing. I ADORED that wacky, old lovable guy! But the telescope was lost during a move from California to Oregon. DANG!!! Will try to replace it with something commercial soon.
@@sayrock6343 ..Why replace with a commercial one?...Why not make another one again by yourself sir. . .& give tribute to that wacky, old lovable guy?...I mean, you're having the proper skills & you know the art...Then why not a 2nd one?...Though I know that a commercial one would be more advanced, accurate & powerful & able to push you far into the galaxy. . .nevertheless. . . 🙂🌌
@@brendangilmore4297 I heard all the oohs and aaaaahs from the viewers and I expected to see an image of the moon, but it never came. I was just a little disappointed. Never-the-less it was a great project.
I built a telescope like this after watching this video, it was a big chew!...I wouldn't do it again because telescope are cheap enough to not put yourself through all this.
From 5:43 when he just picks up the glass blank and uses it as a hammer to drive in a bare nail into the table, I laughed so hard. This would be inconceivable in any ATM grinding video today. A tribute to the DIY spirit of the man and the times.
His methods weren't half as crude as back in the ancients' days of yore. He was an optical engineer that grew relaxed in his work, knew what he could get away with and what he couldn't.
@JackSpeed 439 Sounds reasonable. Early camera's contained a huge glass negative with a layer of emulsion. And the lense was huge, too. The picture quality was great. Size matters, in optics. Image size on film or ccd is important.
+Augustus noo!!! 😢😢 a few min in, i checked the date of the video and wondered if he was still alive. as a writer, i saw the tragedy of the possibility that i am hearing all this wisdom and detail in his craft, and that it would be such a gift made sober if he had died. and i was right. 😢😢 i hope his kids (and their kids) appreciate this video as i do, and i never knew the man.
What you might never guess is his enthusiasm at star parties. The original "sidewalk astronomer" would explain patiently to kids of all ages what they were looking at, why it was interesting and what else they could see tonight. He could be impatient at times but his passion for astronomy was a force that was undeniable. I'm glad to have met him several times over the years. I think he inspired the DIY in all of us, and certainly contributed to the Maker movement. RIP Dobby
John Dobson you are not a teacher or builder; you are an institute. I loved watching every seconds of this video. Every words that came out of John's mouth; carry a lot of weight; wisdom, passion, and dedication. Long live John. Thank you.
This is an amazing video from a truly amazing man. John Dobson selflessly contributed more than anyone in history to the hobby of amature astomomy. He will be missed. I can only hope that some of the extremely fortunate people that he personally trained will continue to pass down the skills he demonstrated so well in this video. If there is an 'Academy Award' for CZcams videos, this one wins for "Sharing the Knowledge of a Master in the Arts"
Glad somebody finally put this on CZcams. This was produced about 25 years ago and I still have a VHS of it. Looking to get a DVD. Great video of his methods.
Wow thank you for posting this. I've heard so much about this man and his contribution to amateur astronomy and I never expected to be able to see a video of him teaching how he made his telescope. Mr. Dobson was a legend back in 1980 when my physics teacher raved about him. His revolutionary design put 10+ inch "light buckets" within monetary reach of amateurs. 8" was about the top of the heap at that time, and even then considered a luxury. Back then a factory -made 12", 16", or 24" telescope would cost more than a new car, and that kind of aperture was pretty much just the domain of universities. What an awesome video !!!!
May he rest in peace. Today, 24 March 2020 is the first time I came to know about this inspiring man through CZcams, yet I watched this entire video and it was, for all there is, a joy for me to watch. I hope his legacy and contributions will always be remembered.
He invented the type of telescope. Sadly he passed in 2014. Of course Bob Ross passed as well. You know what Bob Ross did before he was a painter? You ever see the movie Full Metal Jacket? He was the R. Lee Ermy guy. czcams.com/video/hsPBcCIvDSg/video.html
Mr Dobson Lived a nice long life 98 years Young passed away in 2014 He was a Monk and had a Masters Degree in Chemistry and Co founded Side Walk Astronomers getting people interested in Astronomy, from the Side Walk. This video will carry his lessons on for years and years
If we as a whole... had more people like Mr. John Dobson....this world be more beautiful. to teach with patience and understanding is the key to a better learned society. give me a fish...I eat for a day. teach me how to fish...I eat for a lifetime. teach me how to farm....I can feed a whole community. So....Teach with patience and understanding.
My Dobsonian - I was riding my bike for fun one fine evening. It was 'trash day,' and at the curb for trash pick-up the next morning was a factory-built Odessey brand 10" Dobsonian telescope. I asked the homeowner if I could have it, and he said yes, and brought out the five eyepieces that went with it. I called home and got my wife to bring the car around, and to home it went! This great find was built with the best available drive of its era, the Dob Driver II. What a fabulous find - not only a great beginner scope, but also a nice set of accessories, and the Dob Driver II already installed! The DD II had stepper motors and a small electronics handheld. It ran on 12 volts, gel batteries. You could release the drive belt tension and move the tube by hand, then secure the drive belt and move the tube in small, slow increments using the DD II handheld. After nudging the tube a few times with the DD II hand control, to keep the moon or whatever centered, the Dob Driver II would take over and pretty much keep the object centered all by itself, making tiny movements in two axes, to account for celestial movements. What a great feature. Of course, that was from the early 2000s, and the current full-featured GoTo drives had not been invented yet. Dob Driver still exists as of late 2019 for purchases or service, even of my now very old unit. After seeing all the work of John Dobson and friends to build a Dobsonian scope, I now know I would never have spent so much time and energy to build a scope myself. Truly, the world owes him a huge debt for creating this simple and powerful design, and the name Dobsonian for this type of telescope will be around for a long time. Today one can buy pre-fab Dobsonians. There are also kits, and all the parts like the diagonal and such, so you can build from scratch or assemble from parts.
I still have my 2003 10" Newtonian that I ground and polished under the iron hand of John Dobson. He cut me no slack as many of you probably had the same experience with him.
You are a lucky person to have known him and learned from his mastery. I just started in astronomy and got my first 76mm reflector with 700mm focal length a week ago. Being able to create your own telescope must be one of the most satisfying things an astronomer could do. I'm still in awe looking at just the moon with a 10mm eyepiece through a 2x barlow and seeing real craters and mountains on something so small to the naked eye. I hope you are still viewing the skies and enjoying astronomy. A 10" Newtonian is probably something I will never own. So congratulations that you own one and you make it yourself! Impressive.
Angelaina Marie this video provides quite a nice walkthrough of building one, but it also leaves a fair bit of detail out. For instance, what is he looking for when he holds the mirror up dad using fine grinding? Why 8’ exactly? I suspect this video is leaving bits out, and I’m wondering how to find out more. Where did you learn to make one? Thanks!
I love you John. and thank you for sharing this with us. I took a telescope making class from John at the natural history museum in Golden Gate park, in 1973. I still have my 16.5" telescope. I learned a lot about astronomy from him.
John stayed with my family for nearly a week 30 years ago. He left a profound impression on us! He is by far the most profoundly intellectual person I have ever met.
"This is the 60 grit part of the lawn. We'll move to another part, for 80 grit." You know you're serious, when areas of your lawn are classified by different grits.
"Diseases of the tool are not contagious to the mirror," it's awesome to hear such homespun kind of mnemonics applied to something as exacting as high-fidelity telescopic mirrors.
ikr? the beautiful clash of scientific instruments and man-of-the-earth ... spirituality might be the best word for it, is what makes this video so valuable.
It’s amazing that he needs nothing but a reflection of the sun on a convex surface, a tape measure and a sharp eye (and mind) to correct a mirror. No Foucault test or any other precision measurement to tell him what to do. This video is gold.
Aaron- True but my five inch Maksutov is f12 so it too could be judged quite casually. A real Schmidt camera can be f 1.0 and the focal "plane" is not a plane so I guess I’d have a lot of reading to do to figure out how to test one. Hmm... I wonder where you get a sensor array that’s spherical? Or... can a sensor take that much bend? In my case it really doesn’t matter. I’ll never get around to making one. I can afford to buy one and I don’t have the ROOM to make a mirror. My apartment is a workshop but it’s RC planes, fiddles and celli. One lifetime is not enough to do everything but trying is fun.
Aaron- I started a 4.5 inch scope of unusual design many years ago. I sent the mirror out to be aluminized and it came back with 3/8ths or a half inch of frosting because what looked good to my eye was incompletely polished. I stuck the scope together anyway. I had made the tube and a holder for reflector which was a nice aiming device. The holder was centered on some motorcycle spokes and the nipples were used to center the holder. The hole in the mirror center held a blackened brass tube an inch or more in diameter. I probably had to take an inch or more off the telescope tube because my 24 mm eyepiece had to be stuck directly into the tube. I got (as expected) a very low contrast image about 40X estimated. In a week or a month I took it all apart, wrapped copper magnet wire around the central piece of the mirror and used plaster of Paris to "glue" it in place, using the tool to line stuff up. I stared polishing but lost interest. I still have all the glass except for the tool the unfinished mirror is still only six feet away from where I do most of my work, The central piece is still plastered in and the copper wire I planned to use for disassembly is still ready to do its job.
Such wisdom! I'm stealing this for my own classes; though I'll give him credit, of course. So many students believe exactly the opposite (I guess that's why he says it).
Somewhere in the 80'ies I saw John in an astronomy series on TV. There he walked around and let people on the street see the sky through his homebuild telescopes. It is so nice to see that he still have such a passion for the homebuild telescopes and for teaching.
This was probably the best hour and a half I've spent in quite some time. With the Bose QCII's on cancelling out the noise of the world focused, no pun intended, on someone who has definitely left his mark. I too wish I had seen this years ago as I've only recently gotten back into astronomy, and go figure, as my eyes are starting to go. If more of today's youth were to put down the tablets and game controllers and actually get interested in something more than their Fortnite Ranking and how many social media followers they have, the future of our spinning little rock might be headed into a better direction. God Bless All of You Making A Difference and Changing Your Stars. My Three Cents.
This put the warmest smile on my face, especially when he pulled a pocket knife out from his pocket. Thank you! "The dream is in the Dreamer, and the dream is alive"
What an amazing man, a great and knowledgeable teacher, it's sad to think there aren't enough John Dobson's in the world, a man driven by passion and not money, I can only hope he is in a greater place and that their is more people in the world like this.
I hope there are individuals "out there" that contains at least Some of the knowledge he possesses. I would LOVE to take a class like this! I appreciate his patience with his students lack of skill in certain parts of the video. He has the heart of a teacher and appears to be almost bursting at the seams with his enthusiasm at sharing his knowledge and skill with this subject
When I was in High School I tried to make a 6” telescope. I ground it for hours and hours but I never got it to really go concave. Finally I sent to to a commercial shop to finish it. This is a lot harder to do than it looks. (Having John Dobson there to show you how it’s done is about as good as it gets to learn. :) )
True brilliance is when something complex can be explained and /or demonstrated simply. Thank You John Dobson for your legacy , a rare inspiration to the astronomical world.
Yes, he was a master at putting complex ideas into laymen's terms. He also taught an astronomy class. A typical example was how he described the density of the planet Mercury . . . "three battleships in a one pint jar." The man was a beloved treasure! Since buying the Discovery Channel's DVD called How the Universe Works, I've missed him more than ever. Oh, what I wouldn't give for one more opportunity to sit and listen to him talk.
This was one of the best video's I've seen on CZcams. Sat down and watched through every minute of it. It also inspires me (as a person in their mid 20s) to be more patient with my own craft, because the payoff makes it all worth while.
If they haven't yet, they need to name a celestial body after John Dobson. Great video. A friend of mine gave me this on VHS years ago and I lost it moving between states. This was such a wonderful recommendation by the youtube gods.
Absolutely splendid ! I couldn't turn it off ! I have watched thousands of videos on hundreds of subjects. This man beats most DIY people hands down.!!
I built a six inch reflector on a Dobsonian mount back in the 1990's, but never knew the history of WHY it was called that. I just watched this video, totally blown away by the dedication of this man and his knowledge.
This was an amazing hour and a half. I never appreciated how *easy* it is to build such a fine instrument. To all the commentators complaining that the process took to long and just buy the mirror., please consider that a machine finished mirror will still cost several thousand, and there is no guarantee that it will be as good as this one.
For those more interested in the astronomy than in the how you got there, I'd love to see an updated version of this size telescope constructed from scratch, but in the age of Amazon and eBay (and their generics.) Much of it would be similar, but no doubt you can order an unsilvered mirror, needing perhaps a final polishing, obtain appropriate bearings and hardware for the fine adjustments, etc., in a way that would have been untenable even ten years ago. If it's the time and labor and astounding results from the simplest of materials you crave, this is of course the gold standard. As someone mentioned earlier, though, it would be fun to see the "This Old Tony" or "Wintergaten" version.
Very thankful that you uploaded this video for us. I hope that the legacy of John Dobson, coupled with this video, inspires many more people to make their own telescopes. Thank-you.
I'm 17 and love astronomy. recently I made a 50mm refractor. its my first telescope. and now I was searching some information to make a dobsonian telescope. and now I saw this video of mr. dobson. And litraly I got every thing that what I was searching for.
I attended Johns Telescope building and cosmology classes at Berkley's Lawrence Hall of Science back in 1972 when I was a 12 year old kid and man was John a very animated teacher. I built an 8" out of Port Hole glass which is still in use to this day. RIP John
I ground a 6" mirror in my teens out of a cast Pyrex blank. The classic book, "How to make a telescope" by Jean Texereau was my guide. Wanted an f8, turned into less than an f5... 😋. Very exciting during the polishing stage as the mirror got more and more reflective and rough testing its image making capabilities. Got it reasonably well figured but never quite good enough to merit aluminising or silvering it. Still, it worked well enough on the moon, better than my cheap store bought 40mm refractor... 👍. Thorough completion of stages as well as cleaning is paramount as I learned the hard way a few times, requiring me to go back and repeat previous stages. The name Dobson was well known back then, great to see the man in action... 😁.
This vid blew me away. I have many friends with Dobbies,, many great evenings seeing unimaginable deep space objects. Now to be personal with the person that invented those evenings! This is what the Internet was intended, as was mentioned previously.
I had the pleasure of seeing a lecture by John in Thousand Oaks, CA around 2002. He spoke about the Cosmos recycling itself at "frontier" as he called it, rather than the usual cosmological models. Somewhere deep in my stored boxes I have a DVD-R and John sings beautifully at the end while playing some exotic keyboard instrument, possibly a clavsichord. Can't wait to get that out of storage. His originality is almost non-existent these days.
This is a great video I watched it twice. The method John used to grind and polish the mirror is so simple it motivates me to try and make my own. I even used some aspects of the telescope John built in this video to improve my home made telescope.
Man, he eyeballs a lot at the start. I'm looking at measuring tape and ruler in first 45 minutes. You can tell he's done this many , many times and he is THE MASTER. I love this video. This is what I call video worthy of downloading and saving on secure media.
This morning! I actually have one on my study wall, (From the hard drive of my childhood banks NorthStar Horizon computer) don't plan on using it as a glideplate, though.. :p
Besides coating the mirror, this is a low-tech project almost anyone with the drive, determination and knowledge of Mr. Dobson, could do today. No computers no CNC needed! Though I admit it might be hard to find two pieces of porthole glass to make the tool and the mirror.
He stopped using porthole glass because it was so thin, it easily warped with changing temperatures. He switched over to using thick "plugs" of Pyrex glass. That's what I used when I made our telescope back in the 80's.
@@ericperkins3078 Perhaps but I'd think a lazy-susan should work just about as well, or for the more budget-conscious, the plastic thing in old microwaves that helps the glass plate turn smoothly. Might not be exactly to his spec, but if it works, it works.
Me too. First thought was “I’m old enough and experienced enough with computers from back in the day; from tape reels to the ol’ compaq pressario, line of site data transmission and fiber optic networking. What laser disc looking, magnetic disk is that from? I’ve ripped apart 5.25’s and 3.5’s, different tapes and Zip drives. Looks familiar but unrecognizable. Never heard of a 16 inch disk drive.”
@@jlondon1441 Did you hear the sound when he set it on that wood? I think that is polycarbonate. Probably from a 14 inch disk pack. Did he say it was 16 inches and I missed it? 49:44 Yeah he says it's a 14 inch disk. Could very well be from an IBM CE Pack, a few companies made them, not sure who made this one. The 1311 was the first computer to use 14 inchers back in the 60s and the CE pack would have held 6 of them. You got me wanting to rewatch this now, just to find more clues as to where this brown beauty came from. Google "1316 Disk Pack" for some good images.
I was going to suggest they are older mainframe discs. Some of the larger drives that were used in mainframes up until the late 90s early 2000s. I replaced a few in my day and the things are mighty. I used more modern drives, and others tore them out on account of the weight. Dave at EEVblog actually tore one down on video once. You could likely search it up. But I think your right there likely even older than the ones I am vaguely familiar with.
I've been looking for a good video like this with John Dobson in it. A great amount of info and Mr. Dobson takes no prisoners. He was a very serious man. He comes across as very arrogant but when your a world class expert with his well of knowledge it's not arrogance its experience. Just awesome.
"There's nothing you can do that will be followed by a life of sorrow", wise words. Reminds me of, "there is far greater risk of giving up killing your project than any type of failure."
I've seen the moon at 75x magnification with my 6" newtonion and it looked amazing. I can only imagine what it must look like through a 16" beast like this. I guess I'll have to make one to find out :D What a magnificent video and what a gentleman and expert craftsman. I feel inspired after watching this video.
I used 168x magnification on the moon with a 150mm reflector (about same size as yours), with no problem. You don't need a huge reflector to get detail from the moon and most planets, since they're so bright and aperture only gets you more light. Just attach something like a 2x barlow to a low focal lenght ocular (10 mm or so).
Only if they're talking about trying to use more than a reasonable maximum mag per inch of aperture. Nothing wrong with going past 200-250x if you can for planets, double stars, and small planetary nebulae.
***** Wow, my 30 years of observing experience has all been a lie then...who knew. Let me fix your earlier statement for you, "people who try to sell you telescopes based on inflated claims of magnification are stupid." On the other hand, no one ever looked at Saturn at 75x and said, "No thank you, this is enough magnification."
***** I'm content with my C-14 Edge and TEC-140 for lighter travel, personally, because to do anything serious I need to take a 30 minute drive out into the dark. But more power to you and dark skies...I'm sorry you feel the need to cop such an arrogant, douchebag attitude about it all, though. Thankfully I rarely run across your sort in our local club.
Completely agree with you, John Michaelson, I'm not going to use 500x magnification on my 150mm reflector, that would be unrational, but it is perfectly capable of going up to 200x and get nice detail from moon and planets.
This guy is a legend... a practice like this is something that will be lost in a few generations.... this guy could have made a telescope better than the average mass produced ones with a few broken bottles and a good hot forge and some sanding grit...
Took me awhile to realize this was filmed in the 90s. Good quality. Everyone around him is acting like they're in the presence of a magician. They don't exactly know what's going on, or what may happen next, but they fully believe in magic.
I read an article about him years ago. Never thought I would have the opportunity to see him teach telescope making. As humans, we are transcending time and space through the internet.
Holy ...! I know that Newton ground lenses, but I had always assumed (that useful modern) concave mirrors required unobtanium kit. Watching this blows my mind, although by no means do I mean "Oh, it's that easy" This is incredible! It's art. And what the heck do the 257 people who disliked this video actually do with their days? I'm just curious.
This was an amazing video, by an amazing person, the inventor of the Dobsonian telescope. John developed this design to bring larger reflector telescopes within reach of more people. I have several books on telescope making and will add this knowledge and these well thought out tricks of the trade to that data.
My word! I learned so much, so easily, by listening to this easy-going fellow, Mr.Dobson. If only every teacher was able to explain the whys and wherefores of all subjects!! The ironic fact is I have no interest in actually making a telescope, just wanted to know how it is done. Thank you, John Dobson....
5:07 I was expecting for him to say “look on the Internet”. But, this video was recorded in 1992. There was no Internet. Sometimes I really miss those days.
He could probably figure out how to use a router on a pivot along with a lazy susan to make the concave. Or maybe he'd use his table saw with a cove sort-of thing. Either way, yeah, he would probably find a way to make it work!
@@steventhehistorian Beware as John says at the beginning of the video of machine grinding a lens. NASA spent millions on a machine ground lens for Hubble and it was in storge for two years when the launch was delayed. So confident were that that machine got it right it was never really tested! What happened at first light? Spherical aberration the mirror was out of focus because it was spherical, not parabolic... John',s test well some water, steel tape measure and a piece of card to test focus you can not get much simpler than that and NASA did not do it. Readers Digest published an essay by the guy who was in charge of the NASA grind. It's worth a read if you can find it because in hindsight it shows how mighty are the fallen when overconfidence is at work.
@@@neilshuker-harris5101 Words of wisdom, Neil. You're right. Now you have me worried about where else I may exercise hubris and not realize it. I wasn't able to find the essay you mentioned but I did find NASA's system failure report (ntrs.nasa.gov/search.jsp?R=19910003124) which states, in so many words, that the Hubble failure was due to a negligent and short-sighted (no pun intended) managerial decision. This was definitely not a great look for NASA who was, at the time, still dealing with the fallout from the Challenger disaster... Another example of horrendous managerial decision-making. So your point is well taken, lol. I retract my prior statement that this work could be done more efficiently with machinery. You sound like a man with knowledge, experience, and wisdom. Thank you for sharing!
WOW! I'm so glad CZcams suggested this video to me this evening and to the person who uploaded it. This is just fantastic stuff. People like John Dobson just seem to be a rare breed these days...I really do hope he passed his skills on to a few people who keep this trade/skill alive. :-)
A large pottery wheel can take a lot of the physical labor out of this process if you have the luxury of having one in your optics shop. If you have done many of these you know the amount of time it takes grinding glass. Use pitch to hold the glass centered. Repeatable consistent movement will help you with concentriscity and can be very helpful for beginners getting into this hobby. A pottery wheel is grit and water resistant too. Shoot for the stars my friends. :D
I'm not likely to grind my own mirror, but I'm thankful for John's contribution to astronomy. Once upon a not too distant past, a 6" f/8 was "big." John smashed that notion. I rather enjoy my 12" f/5 and 8" f/6.
Few and far between I get excited about roughing and finishing. This gives a whole new dynamic. Is it me? Or does the scenario with the pitch lap come to mind with others... "Stick" like ... scalpel! Like a surgeon. I am humbled because this is by hand. Truly artisan beyond. Thanks Dr. Dobson. Myself 35 yrs. primarily metal and polymers. But, thank you for testimony and proof anything can be done by hand with time, experience and proper process.
This is a historical document. Nice to see it preserved on CZcams. The Internet wins when humans can share content like this.
I took the telescope making class from John at the natural history museum in San Francisco. I built a 16 inch telescope in 1972. I still have it
Bet learned lot more from hm he was a Monk after all.
That's awesome, thank you for sharing! :)
@@FOOKCZcamsNUMBERS that story about the little sparkly boy @9:10 I found rather disturbing.
Awesome
@@Vintage_USA_Tech y
In April 1974 my wife and I decided to tour the deserts of the southwest. We saw the Mojave, the Sonora, Joshua Tree and finished with Death Valley. It was one of the best wild flower displays in a century. In Death Valley, we drove up to Dante's View, an elevation on the east side of the valley with a view of the entire valley and across to the Sierras to the west. The parking lot was full of vans, home-made telescopes and people just lazing around. A polite, very tanned man in shorts invited us to return that evening to see the stars. We spent the remainder of the day touring the valley, but did return at dusk to meet John Dobson and the Sidewalk Astronomers of San Francisco. We spent the entire night viewing the heavens as I had never seen them, and I got my first look at the Magellanic Clouds. John said, "Why spend tens of thousands of dollars on a telescope you cannot move? Build your own and buy a van to transport it wherever you want." My interest in astronomy has never waned since that night and I now have two grandchildren to pass this wonder on to. Thank you John.
The moon is only as far as you can see. I'm thinking about 300 yards up in the sky. My gun scope tells me how far things are from it.
The Magellanic Clouds? From Dante's view?
That is way too far north to see them.
Unless you meant you saw them in a photo of course.
@@BeardyBaldyBobthe clouds are to far north unless the earth is actually is flat.__
@@BeardyBaldyBob perhaps he was being a little sloppy with his language and he just meant the milky way. LMC/SMC cant be seen north of about the 20th parallel. I like his story, but I had the same reaction :)
Touching account..envy u guys who made their own telescopes...
Yes, J. D. was a driven man. I forgot to ask him if, since he was born of missionary parents in China, his parents used to talk to him about finding his " mission ". That's what John had -- a mission. Don't forget he spent 21 years as a monk in theVedanta Society monastery ( the" Monstery" , he called it ). Only when he got ejected did the Sidewalk Astronomers begin. I met him in 1976 at age 22 at Bush St. John knew the trails on Mt. Tamalpais upside and backward. He knew the names ofall the flowers and plants. We used to hike along the old railroad grade and hunt for half - buried spikes. And what an aggressive driver ! He'd sit behind the wheel in consternation at some other driver's indecision and say, in his sing - songway ..." May I inquire, what are your Plans ?" I went on three summer tours in the 80s, then moved into Baker St. Him in thebasement ( loved to watch Quincy M.D. ) and me up near the attic. J.D. taught me how to cook, and boil a chicken. He usedliquid lecithin to make us fried eggs. " Look at 'em slide !, Mr. Doug " Then we'd have a home- made "Green Drink" withRomaine and peanut butter. And man, did he love to give a talk ! Or sing some song he'd dug up from Orpheus, of all people,on his weirdly tuned guitar....Loved to teach us to chant the hymns of Shankara.....But the funniest thing about J.D. was theway he'd just " melt " in the presence of some Big - time Swami from India. When he went there the customs officials wouldn't let the telescopes out of quarantine !! So he had to give slide shows. Just about the best compliment I ever gotwas when John called me a " Hard - core " Sidewalk Astronomer. One more little antic - dote : When we were at Rocky Mtn.State Park , he got madder than usual at the smokers , and suggested to me they should be made to EAT their cigarette butts.I knew my man, so the next morning I was up at sunrise and picked up all the butts ! A little later J.D. came bursting out ofthe motor home with a small paper bag in his hand. " Wha -- wha happened to all the ..... ? " then he caught my eye and we hada chuckle. Well, that was FUN. John Dobson was like a Father to me.
yin taichi Mr. Doug Snider,.... Long time no see :)
thanks a lot for sharing, he really looks amazing.
yin taichi: "what an aggressive driver!"
video: 44:16
me: his story checks out so far.
Thank you for sharing this long post! May i quote you? Im writing a little page about telescopes including the huge ex-soviet optical/radio scope in Argatz which hopefully will get repaired.
Wow thank you for sharing this
What an amazing video. Rarely does a video catch my attention for an hour and a half without me noticing time go by. Thanks Mr. Dob for the gift you gave to humanity.
right? i was pulled right in from the start.
I was fortunate enough back in the 80s to take John's telescope making class. Built one with a hand-ground 12 inch mirror. You could see the rings around Saturn through it!! OK, so it was NOT like a fancy photo from Astonomy magazine, it looked more like a large white dot with a string circling around it, but dang it, it WAS Saturn! How I miss John. My heart still aches over his passing. I ADORED that wacky, old lovable guy! But the telescope was lost during a move from California to Oregon. DANG!!! Will try to replace it with something commercial soon.
@@sayrock6343
..Why replace with a commercial one?...Why not make another one again by yourself sir. . .& give tribute to that wacky, old lovable guy?...I mean, you're having the proper skills & you know the art...Then why not a 2nd one?...Though I know that a commercial one would be more advanced, accurate & powerful & able to push you far into the galaxy. . .nevertheless. . . 🙂🌌
As a Mechanical Engineer, I wish I knew this method before when I was in college. But I was glued to this video for the entire 1:29. Love the Sky !
Ditto
Sameee ❤
Will I ever build a telescope? Nope! did I watch this whole video? Yup! this guy is a master at his craft and it is a joy to watch.
I was thinking exactly the same thing. It's satisfying just watching an enthusiastic master at his work :)
@@brendangilmore4297 I heard all the oohs and aaaaahs from the viewers and I expected to see an image of the moon, but it never came. I was just a little disappointed. Never-the-less it was a great project.
WAI YU NO BUILD????!11???!??
@@RogerBarraud i would really like to and maybe someday I will. I just don't have time or money right now.
I built a telescope like this after watching this video, it was a big chew!...I wouldn't do it again because telescope are cheap enough to not put yourself through all this.
From 5:43 when he just picks up the glass blank and uses it as a hammer to drive in a bare nail into the table, I laughed so hard. This would be inconceivable in any ATM grinding video today. A tribute to the DIY spirit of the man and the times.
He really understood his materials.
His methods weren't half as crude as back in the ancients' days of yore. He was an optical engineer that grew relaxed in his work, knew what he could get away with and what he couldn't.
@JackSpeed 439 yup! I'd go with that thought.
@JackSpeed 439 Sounds reasonable. Early camera's contained a huge glass negative with a layer of emulsion. And the lense was huge, too. The picture quality was great. Size matters, in optics. Image size on film or ccd is important.
Same. I loved so hard considering I've cracked a mirror with a small drop while cleaning it.
I think he said he used a porthole from a ship?
Sir, you were a truly great, generous man.
RIP John Dobson.
We need more John Dobson's in the world. God bless you John Dobson.
Again I have returned to John Dobson. What a man, I wish I had got into astronomy much earlier. Imagine attending a class he conducted!
+david duffy I respect him very much for his works.
+Joe N. He died a few years ago, you know that, right?
Augustus Yes. But I still respect him. If I said "respected" it would seem like I no longer respect him. :)
+Augustus noo!!! 😢😢 a few min in, i checked the date of the video and wondered if he was still alive. as a writer, i saw the tragedy of the possibility that i am hearing all this wisdom and detail in his craft, and that it would be such a gift made sober if he had died. and i was right. 😢😢 i hope his kids (and their kids) appreciate this video as i do, and i never knew the man.
What you might never guess is his enthusiasm at star parties. The original "sidewalk astronomer" would explain patiently to kids of all ages what they were looking at, why it was interesting and what else they could see tonight. He could be impatient at times but his passion for astronomy was a force that was undeniable. I'm glad to have met him several times over the years. I think he inspired the DIY in all of us, and certainly contributed to the Maker movement. RIP Dobby
John Dobson you are not a teacher or builder; you are an institute. I loved watching every seconds of this video. Every words that came out of John's mouth; carry a lot of weight; wisdom, passion, and dedication. Long live John. Thank you.
This is an amazing video from a truly amazing man.
John Dobson selflessly contributed more than anyone in history to the hobby of amature astomomy.
He will be missed.
I can only hope that some of the extremely fortunate people that he personally trained will continue to pass down the skills he demonstrated so well in this video.
If there is an 'Academy Award' for CZcams videos, this one wins for "Sharing the Knowledge of a Master in the Arts"
Glad somebody finally put this on CZcams. This was produced about 25 years ago and I still have a VHS of it. Looking to get a DVD. Great video of his methods.
Wow thank you for posting this. I've heard so much about this man and his contribution to amateur astronomy and I never expected to be able to see a video of him teaching how he made his telescope. Mr. Dobson was a legend back in 1980 when my physics teacher raved about him. His revolutionary design put 10+ inch "light buckets" within monetary reach of amateurs. 8" was about the top of the heap at that time, and even then considered a luxury. Back then a factory -made 12", 16", or 24" telescope would cost more than a new car, and that kind of aperture was pretty much just the domain of universities. What an awesome video !!!!
May he rest in peace. Today, 24 March 2020 is the first time I came to know about this inspiring man through CZcams, yet I watched this entire video and it was, for all there is, a joy for me to watch.
I hope his legacy and contributions will always be remembered.
This dude is the Bob Ross of telescope building. Beautiful person.
He invented the type of telescope. Sadly he passed in 2014. Of course Bob Ross passed as well.
You know what Bob Ross did before he was a painter? You ever see the movie Full Metal Jacket? He was the R. Lee Ermy guy.
czcams.com/video/hsPBcCIvDSg/video.html
@@erictaylor5462 To be fair (to Newton), John invented a type of telescope mount. Still a legend, though. I have my 10" Dobsonian and it's wonderful!
@@itaialter indeed
@Bob Ross lol. I love you man. I know its all beautiful trees and happy squirrels in the afterlife. Tell me it's so.
@Bob Ross No one. Go back to sleep. You've done your part and can rest now.
Mr Dobson Lived a nice long life 98 years Young passed away in 2014 He was a Monk and had a Masters Degree in Chemistry and Co founded Side Walk Astronomers getting people interested in Astronomy, from the Side Walk. This video will carry his lessons on for years and years
If we as a whole... had more people like Mr. John Dobson....this world be more beautiful.
to teach with patience and understanding is the key to a better learned society.
give me a fish...I eat for a day.
teach me how to fish...I eat for a lifetime.
teach me how to farm....I can feed a whole community.
So....Teach with patience and understanding.
Give me 100 fishrods, I'll make 100 people fish for me and give them 50 fish and sell the rest. Oh thats capitalism.
I cannot imagine how satisfying it would be to peer into the universe with a tool you built yourself.
I sat next to him at a star party and attended a couple of his lectures in Oregon. Super great man !
+Andy Rusten you are lucky!
My Dobsonian
- I was riding my bike for fun one fine evening. It was 'trash day,' and at the curb for trash pick-up the next morning was a factory-built Odessey brand 10" Dobsonian telescope. I asked the homeowner if I could have it, and he said yes, and brought out the five eyepieces that went with it. I called home and got my wife to bring the car around, and to home it went!
This great find was built with the best available drive of its era, the Dob Driver II. What a fabulous find - not only a great beginner scope, but also a nice set of accessories, and the Dob Driver II already installed! The DD II had stepper motors and a small electronics handheld. It ran on 12 volts, gel batteries. You could release the drive belt tension and move the tube by hand, then secure the drive belt and move the tube in small, slow increments using the DD II handheld. After nudging the tube a few times with the DD II hand control, to keep the moon or whatever centered, the Dob Driver II would take over and pretty much keep the object centered all by itself, making tiny movements in two axes, to account for celestial movements. What a great feature. Of course, that was from the early 2000s, and the current full-featured GoTo drives had not been invented yet. Dob Driver still exists as of late 2019 for purchases or service, even of my now very old unit.
After seeing all the work of John Dobson and friends to build a Dobsonian scope, I now know I would never have spent so much time and energy to build a scope myself. Truly, the world owes him a huge debt for creating this simple and powerful design, and the name Dobsonian for this type of telescope will be around for a long time.
Today one can buy pre-fab Dobsonians. There are also kits, and all the parts like the diagonal and such, so you can build from scratch or assemble from parts.
What a gift, a privilege, to watch this great man build a telescope from scratch! Thank you.
I still have my 2003 10" Newtonian that I ground and polished under the iron hand of John Dobson. He cut me no slack as many of you probably had the same experience with him.
You are a lucky person to have known him and learned from his mastery. I just started in astronomy and got my first 76mm reflector with 700mm focal length a week ago. Being able to create your own telescope must be one of the most satisfying things an astronomer could do. I'm still in awe looking at just the moon with a 10mm eyepiece through a 2x barlow and seeing real craters and mountains on something so small to the naked eye.
I hope you are still viewing the skies and enjoying astronomy. A 10" Newtonian is probably something I will never own. So congratulations that you own one and you make it yourself! Impressive.
I'm on my second Dobsonian scope, of my life. They are truly a gift, I simply adore watching the inventor make one.
Angelaina Marie this video provides quite a nice walkthrough of building one, but it also leaves a fair bit of detail out. For instance, what is he looking for when he holds the mirror up dad using fine grinding? Why 8’ exactly? I suspect this video is leaving bits out, and I’m wondering how to find out more. Where did you learn to make one? Thanks!
I love you John. and thank you for sharing this with us.
I took a telescope making class from John at the natural history museum in Golden Gate park, in 1973. I still have my 16.5" telescope.
I learned a lot about astronomy from him.
John stayed with my family for nearly a week 30 years ago. He left a profound impression on us! He is by far the most profoundly intellectual person I have ever met.
That hour and a half video felt subjectively like a half hour. I wish I had known this amazing man. A natural teacher.
"This is the 60 grit part of the lawn. We'll move to another part, for 80 grit."
You know you're serious, when areas of your lawn are classified by different grits.
It's amazing how a precision instrument can come of such crude steps. Mr. Dobson carried on the spirit of Russell Porter.
"Diseases of the tool are not contagious to the mirror," it's awesome to hear such homespun kind of mnemonics applied to something as exacting as high-fidelity telescopic mirrors.
ikr? the beautiful clash of scientific instruments and man-of-the-earth ... spirituality might be the best word for it, is what makes this video so valuable.
It’s amazing that he needs nothing but a reflection of the sun on a convex surface, a tape measure and a sharp eye (and mind) to correct a mirror. No Foucault test or any other precision measurement to tell him what to do. This video is gold.
Aaron- True but my five inch Maksutov is f12 so it too could be judged quite casually. A real Schmidt camera can be f 1.0 and the focal "plane" is not a plane so I guess I’d have a lot of reading to do to figure out how to test one. Hmm... I wonder where you get a sensor array that’s spherical? Or... can a sensor take that much bend? In my case it really doesn’t matter. I’ll never get around to making one. I can afford to buy one and I don’t have the ROOM to make a mirror. My apartment is a workshop but it’s RC planes, fiddles and celli. One lifetime is not enough to do everything but trying is fun.
Aaron- I started a 4.5 inch scope of unusual design many years ago. I sent the mirror out to be aluminized and it came back with 3/8ths or a half inch of frosting because what looked good to my eye was incompletely polished. I stuck the scope together anyway. I had made the tube and a holder for reflector which was a nice aiming device. The holder was centered on some motorcycle spokes and the nipples were used to center the holder. The hole in the mirror center held a blackened brass tube an inch or more in diameter. I probably had to take an inch or more off the telescope tube because my 24 mm eyepiece had to be stuck directly into the tube. I got (as expected) a very low contrast image about 40X estimated. In a week or a month I took it all apart, wrapped copper magnet wire around the central piece of the mirror and used plaster of Paris to "glue" it in place, using the tool to line stuff up. I stared polishing but lost interest. I still have all the glass except for the tool the unfinished mirror is still only six feet away from where I do most of my work, The central piece is still plastered in and the copper wire I planned to use for disassembly is still ready to do its job.
"There's nothing that you can do going the wrong way in this class that will be followed by a life of sorrow." - John Dobson.
Such wisdom! I'm stealing this for my own classes; though I'll give him credit, of course. So many students believe exactly the opposite (I guess that's why he says it).
Somewhere in the 80'ies I saw John in an astronomy series on TV. There he walked around and let people on the street see the sky through his homebuild telescopes. It is so nice to see that he still have such a passion for the homebuild telescopes and for teaching.
This video isn’t that much newer than the 80s. Around the 90s somewhere. He died in 2014.
John Dobson's voice is like a Lullaby to my ear and my soul!
Man... your passion is contagious.
RIP you, the brightest star of Milky Way.
This was probably the best hour and a half I've spent in quite some time. With the Bose QCII's on cancelling out the noise of the world focused, no pun intended, on someone who has definitely left his mark. I too wish I had seen this years ago as I've only recently gotten back into astronomy, and go figure, as my eyes are starting to go. If more of today's youth were to put down the tablets and game controllers and actually get interested in something more than their Fortnite Ranking and how many social media followers they have, the future of our spinning little rock might be headed into a better direction. God Bless All of You Making A Difference and Changing Your Stars. My Three Cents.
One of the most interesting and informative "how to" I have ever watched.
It is a pleasure to see this great man. People like this make our world a better place.
This put the warmest smile on my face, especially when he pulled a pocket knife out from his pocket. Thank you!
"The dream is in the Dreamer, and the dream is alive"
What an amazing man, a great and knowledgeable teacher, it's sad to think there aren't enough John Dobson's in the world, a man driven by passion and not money, I can only hope he is in a greater place and that their is more people in the world like this.
I hope there are individuals "out there" that contains at least Some of the knowledge he possesses. I would LOVE to take a class like this! I appreciate his patience with his students lack of skill in certain parts of the video. He has the heart of a teacher and appears to be almost bursting at the seams with his enthusiasm at sharing his knowledge and skill with this subject
A great man, he gave all of humanity a gift.
Aye, he will be missed.
What a revolution John Dobson started. Inspired many home made telescopes. Made large apertures much more accessible for visual viewing.
When I was in High School I tried to make a 6” telescope. I ground it for hours and hours but I never got it to really go concave. Finally I sent to to a commercial shop to finish it.
This is a lot harder to do than it looks. (Having John Dobson there to show you how it’s done is about as good as it gets to learn. :) )
My 8” blank is rough ground, but I ended up giving up nevertheless.
When this old bird started carrying on about in focus, and out of focus I just marveled at how much this guy knows.
+Paul Frederick Like he invented the Dobsonian telescope, of course he knew so much.
True brilliance is when something complex can be explained and /or demonstrated simply.
Thank You John Dobson for your legacy , a rare inspiration to the astronomical world.
Yes, he was a master at putting complex ideas into laymen's terms. He also taught an astronomy class. A typical example was how he described the density of the planet Mercury . . . "three battleships in a one pint jar." The man was a beloved treasure! Since buying the Discovery Channel's DVD called How the Universe Works, I've missed him more than ever. Oh, what I wouldn't give for one more opportunity to sit and listen to him talk.
Mr. Dobson, you were a Master Mirror Maker and a Telescope Titan! Incredible craftsmanship.
This was one of the best video's I've seen on CZcams. Sat down and watched through every minute of it. It also inspires me (as a person in their mid 20s) to be more patient with my own craft, because the payoff makes it all worth while.
Really enjoyed this film from start to end. So informative. RIP JD
If they haven't yet, they need to name a celestial body after John Dobson. Great video. A friend of mine gave me this on VHS years ago and I lost it moving between states. This was such a wonderful recommendation by the youtube gods.
Absolutely splendid ! I couldn't turn it off ! I have watched thousands of videos on hundreds of subjects. This man beats most DIY people hands down.!!
I built a six inch reflector on a Dobsonian mount back in the 1990's, but never knew the history of WHY it was called that. I just watched this video, totally blown away by the dedication of this man and his knowledge.
This was an amazing hour and a half. I never appreciated how *easy* it is to build such a fine instrument. To all the commentators complaining that the process took to long and just buy the mirror., please consider that a machine finished mirror will still cost several thousand, and there is no guarantee that it will be as good as this one.
Easy, no. Low-tech, yes. They did it in the 16th century with not much more tech than this.
@@JasperJanssen Reflecting telescopes were a 17th century idea. And they used metal mirrors.
Fat Roberto lens grinding uses basically the same techniques, and that’s Galileo. More similar to that than the early mirrors, actually.
For those more interested in the astronomy than in the how you got there, I'd love to see an updated version of this size telescope constructed from scratch, but in the age of Amazon and eBay (and their generics.) Much of it would be similar, but no doubt you can order an unsilvered mirror, needing perhaps a final polishing, obtain appropriate bearings and hardware for the fine adjustments, etc., in a way that would have been untenable even ten years ago. If it's the time and labor and astounding results from the simplest of materials you crave, this is of course the gold standard. As someone mentioned earlier, though, it would be fun to see the "This Old Tony" or "Wintergaten" version.
Very thankful that you uploaded this video for us. I hope that the legacy of John Dobson, coupled with this video, inspires many more people to make their own telescopes. Thank-you.
I'm 17 and love astronomy. recently I made a 50mm refractor. its my first telescope. and now I was searching some information to make a dobsonian telescope. and now I saw this video of mr. dobson. And litraly I got every thing that what I was searching for.
I attended Johns Telescope building and cosmology classes at Berkley's Lawrence Hall of Science back in 1972 when I was a 12 year old kid and man was John a very animated teacher. I built an 8" out of Port Hole glass which is still in use to this day. RIP John
"If you've waited this long to drop and break your mirror, you're a fool. You should have done that on the first day."
You're only a fool if you grind out a convex mirror.
Was pretty funny
Was pretty funny
Wow! What a great hands-on demonstration! I always wondered how they ground those mirrors!
It's awesome to see young kids so captivated with this process... which makes me believe this was recorded before the advent of smart phones.
I ground a 6" mirror in my teens out of a cast Pyrex blank. The classic book, "How to make a telescope" by Jean Texereau was my guide. Wanted an f8, turned into less than an f5... 😋. Very exciting during the polishing stage as the mirror got more and more reflective and rough testing its image making capabilities. Got it reasonably well figured but never quite good enough to merit aluminising or silvering it. Still, it worked well enough on the moon, better than my cheap store bought 40mm refractor... 👍. Thorough completion of stages as well as cleaning is paramount as I learned the hard way a few times, requiring me to go back and repeat previous stages. The name Dobson was well known back then, great to see the man in action... 😁.
Crazy that this old man was doing that kind of labor at his age. My hats off to you Mr. Dobson.
HAHAHA :) He was hiking and jogging up hills for about 20 years after this video was made :)
This vid blew me away. I have many friends with Dobbies,, many great evenings seeing unimaginable deep space objects. Now to be personal with the person that invented those evenings! This is what the Internet was intended, as was mentioned previously.
Wow thank you for posting this. RIP John Dobson. You are remembered !
I had the pleasure of seeing a lecture by John in Thousand Oaks, CA around 2002. He spoke about the Cosmos recycling itself at "frontier" as he called it, rather than the usual cosmological models.
Somewhere deep in my stored boxes I have a DVD-R and John sings beautifully at the end while playing some exotic keyboard instrument, possibly a clavsichord. Can't wait to get that out of storage. His originality is almost non-existent these days.
This is a great video I watched it twice. The method John used to grind and polish the mirror is so simple it motivates me to try and make my own. I even used some aspects of the telescope John built in this video to improve my home made telescope.
How did he get the curve in the "tool"? Is the same curve used in every lense?
I love how he's just making this contraption that can see light years into the universe with household items. Absolutely genius.
Man, he eyeballs a lot at the start. I'm looking at measuring tape and ruler in first 45 minutes. You can tell he's done this many , many times and he is THE MASTER. I love this video. This is what I call video worthy of downloading and saving on secure media.
Wow. When was the last time you seen a 14” computer disk! This man is a pure genius
This morning! I actually have one on my study wall, (From the hard drive of my childhood banks NorthStar Horizon computer) don't plan on using it as a glideplate, though.. :p
Thank you for making the video for us all Mr Dobson, wherever you are now , .
;'(
He's smiling down at us through the millions of Dobsonians around the globe!
The care, love and dedication he puts in making the mirrors is just beautiful. I learnt a lot from the process
What an amazing man - using natural principles and adhering to design simplicity to produce extraordinary results -
Besides coating the mirror, this is a low-tech project almost anyone with the drive, determination and knowledge of Mr. Dobson, could do today. No computers no CNC needed! Though I admit it might be hard to find two pieces of porthole glass to make the tool and the mirror.
Not to mention the "computer disk" he uses to fabricate the swivel.
He stopped using porthole glass because it was so thin, it easily warped with changing temperatures. He switched over to using thick "plugs" of Pyrex glass. That's what I used when I made our telescope back in the 80's.
@@ericperkins3078 Perhaps but I'd think a lazy-susan should work just about as well, or for the more budget-conscious, the plastic thing in old microwaves that helps the glass plate turn smoothly. Might not be exactly to his spec, but if it works, it works.
48:28
"...this computer disk."
Damn it, I was following along this whole time!
Me too. First thought was “I’m old enough and experienced enough with computers from back in the day; from tape reels to the ol’ compaq pressario, line of site data transmission and fiber optic networking. What laser disc looking, magnetic disk is that from? I’ve ripped apart 5.25’s and 3.5’s, different tapes and Zip drives. Looks familiar but unrecognizable. Never heard of a 16 inch disk drive.”
@@jlondon1441 Did you hear the sound when he set it on that wood? I think that is polycarbonate. Probably from a 14 inch disk pack. Did he say it was 16 inches and I missed it? 49:44 Yeah he says it's a 14 inch disk. Could very well be from an IBM CE Pack, a few companies made them, not sure who made this one. The 1311 was the first computer to use 14 inchers back in the 60s and the CE pack would have held 6 of them.
You got me wanting to rewatch this now, just to find more clues as to where this brown beauty came from.
Google "1316 Disk Pack" for some good images.
I was going to suggest they are older mainframe discs. Some of the larger drives that were used in mainframes up until the late 90s early 2000s. I replaced a few in my day and the things are mighty. I used more modern drives, and others tore them out on account of the weight. Dave at EEVblog actually tore one down on video once. You could likely search it up. But I think your right there likely even older than the ones I am vaguely familiar with.
All I can say is “thank you”. I was only going to just say thank you. And I did in the middle of the show. But you actually made me cry.
I've been looking for a good video like this with John Dobson in it. A great amount of info and Mr. Dobson takes no prisoners. He was a very serious man. He comes across as very arrogant but when your a world class expert with his well of knowledge it's not arrogance its experience.
Just awesome.
His sense of humour comes out in this video too. He just seemed to not suffer fools lightly.
"There's nothing you can do that will be followed by a life of sorrow", wise words. Reminds me of, "there is far greater risk of giving up killing your project than any type of failure."
I've seen the moon at 75x magnification with my 6" newtonion and it looked amazing. I can only imagine what it must look like through a 16" beast like this.
I guess I'll have to make one to find out :D
What a magnificent video and what a gentleman and expert craftsman. I feel inspired after watching this video.
I used 168x magnification on the moon with a 150mm reflector (about same size as yours), with no problem. You don't need a huge reflector to get detail from the moon and most planets, since they're so bright and aperture only gets you more light. Just attach something like a 2x barlow to a low focal lenght ocular (10 mm or so).
Only if they're talking about trying to use more than a reasonable maximum mag per inch of aperture. Nothing wrong with going past 200-250x if you can for planets, double stars, and small planetary nebulae.
***** Wow, my 30 years of observing experience has all been a lie then...who knew. Let me fix your earlier statement for you, "people who try to sell you telescopes based on inflated claims of magnification are stupid."
On the other hand, no one ever looked at Saturn at 75x and said, "No thank you, this is enough magnification."
*****
I'm content with my C-14 Edge and TEC-140 for lighter travel, personally, because to do anything serious I need to take a 30 minute drive out into the dark. But more power to you and dark skies...I'm sorry you feel the need to cop such an arrogant, douchebag attitude about it all, though. Thankfully I rarely run across your sort in our local club.
Completely agree with you, John Michaelson, I'm not going to use 500x magnification on my 150mm reflector, that would be unrational, but it is perfectly capable of going up to 200x and get nice detail from moon and planets.
This Man is a hero he has given a simple way to observe the Universe!
Making telescope is my passion since
Childhood. I would have been lucky
if, I met teacher like you at that time.
God bless you 🙏
This guy is a legend... a practice like this is something that will be lost in a few generations.... this guy could have made a telescope better than the average mass produced ones with a few broken bottles and a good hot forge and some sanding grit...
Took me awhile to realize this was filmed in the 90s. Good quality.
Everyone around him is acting like they're in the presence of a magician. They don't exactly know what's going on, or what may happen next, but they fully believe in magic.
I read an article about him years ago. Never thought I would have the opportunity to see him teach telescope making. As humans, we are transcending time and space through the internet.
Holy ...! I know that Newton ground lenses, but I had always assumed (that useful modern) concave mirrors required unobtanium kit. Watching this blows my mind, although by no means do I mean "Oh, it's that easy" This is incredible! It's art.
And what the heck do the 257 people who disliked this video actually do with their days? I'm just curious.
This was an amazing video, by an amazing person, the inventor of the Dobsonian telescope. John developed this design to bring larger reflector telescopes within reach of more people. I have several books on telescope making and will add this knowledge and these well thought out tricks of the trade to that data.
Thank you for the upload...rest in peace among the stars Mr. Dobson.
I am in awe watching the Master at work -- so many small but critical lessons, learned over the decades, sharing and teaching so freely.
My word! I learned so much, so easily, by listening to this easy-going fellow, Mr.Dobson. If only every teacher was able to explain the whys and wherefores of all subjects!! The ironic fact is I have no interest in actually making a telescope, just wanted to know how it is done. Thank you, John Dobson....
Wow, what a wonderful resource. Thank you to everyone involved.
5:07 I was expecting for him to say “look on the Internet”. But, this video was recorded in 1992. There was no Internet. Sometimes I really miss those days.
Touching video of a sage man who tried and succeeded in his mission of helping all of us to wonder at the mysteries of the universe, as he did.
This video is a classic for me. Watched John's video back in the early 90's and built my own 10'' F-7 telescope. Still works great today!
This video is just amazing! All parts are DIY...incredible! R.I.P. Mr. Dobson! I am dreaming about a class like that!
Yeah, who needs a proper swivel bearing when u can just rip apart a 70s-ish harddisk. Those are found everywhere :D hehe. Amazing guy. Amazing video.
This Old Tony needs to get into lens grinding.
chris kaprys That would be awesome. However I'm quite sure he'll try to machine it with his time machine-lathe :)
He could probably figure out how to use a router on a pivot along with a lazy susan to make the concave. Or maybe he'd use his table saw with a cove sort-of thing. Either way, yeah, he would probably find a way to make it work!
Matthias Wandell would do the same thing...
@@steventhehistorian Beware as John says at the beginning of the video of machine grinding a lens. NASA spent millions on a machine ground lens for Hubble and it was in storge for two years when the launch was delayed. So confident were that that machine got it right it was never really tested! What happened at first light? Spherical aberration the mirror was out of focus because it was spherical, not parabolic... John',s test well some water, steel tape measure and a piece of card to test focus you can not get much simpler than that and NASA did not do it. Readers Digest published an essay by the guy who was in charge of the NASA grind. It's worth a read if you can find it because in hindsight it shows how mighty are the fallen when overconfidence is at work.
@@@neilshuker-harris5101 Words of wisdom, Neil. You're right. Now you have me worried about where else I may exercise hubris and not realize it.
I wasn't able to find the essay you mentioned but I did find NASA's system failure report (ntrs.nasa.gov/search.jsp?R=19910003124) which states, in so many words, that the Hubble failure was due to a negligent and short-sighted (no pun intended) managerial decision. This was definitely not a great look for NASA who was, at the time, still dealing with the fallout from the Challenger disaster... Another example of horrendous managerial decision-making.
So your point is well taken, lol. I retract my prior statement that this work could be done more efficiently with machinery. You sound like a man with knowledge, experience, and wisdom. Thank you for sharing!
WOW! I'm so glad CZcams suggested this video to me this evening and to the person who uploaded it. This is just fantastic stuff. People like John Dobson just seem to be a rare breed these days...I really do hope he passed his skills on to a few people who keep this trade/skill alive. :-)
That was absolutely amazing from start to end. The poetry and the singing moved me to tears. Great stuff, thank you
This video is a treasure to preserve for the next generations
A large pottery wheel can take a lot of the physical labor out of this process if you have the luxury of having one in your optics shop. If you have done many of these you know the amount of time it takes grinding glass. Use pitch to hold the glass centered. Repeatable consistent movement will help you with concentriscity and can be very helpful for beginners getting into this hobby. A pottery wheel is grit and water resistant too. Shoot for the stars my friends. :D
I'm not likely to grind my own mirror, but I'm thankful for John's contribution to astronomy. Once upon a not too distant past, a 6" f/8 was "big." John smashed that notion. I rather enjoy my 12" f/5 and 8" f/6.
Few and far between I get excited about roughing and finishing. This gives a whole new dynamic. Is it me? Or does the scenario with the pitch lap come to mind with others... "Stick" like ... scalpel! Like a surgeon. I am humbled because this is by hand. Truly artisan beyond. Thanks Dr. Dobson. Myself 35 yrs. primarily metal and polymers. But, thank you for testimony and proof anything can be done by hand with time, experience and proper process.