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250,478 Views • Jun 10, 2022 • Click to toggle off description
00:00 General intro
01:54 Required level of precision
07:12 Measuring surface shapes with interferometry
10:46 Fringe evaluation with DFTfringe
12:12 Optical Pitch polishing
17:19 Making molds using 3D printing
18:18 Results with variable surface tools
21:06 Primary mirror
22:20 Point Diffraction Interferometry (PDI)
26:48 Visual performance
29:58 NO MORE NAPS (featuring Dr. Fullersheit)
Links mentioned in the video:
Website with the best and most detailed information on telescope optics:
www.telescope-optics.net/. This is the direct link to the page about the different criteria and how they relate to aberrations: www.telescope-optics.net/effects1.htm
The 3D-printer used was manufactured by 3Bfab. More information on their products can be found on their website: 3bfab.com/ (not sponsored content - they did neither ask nor pay me to show their product)
DFTfringe software is programmed by Dale Eason. This is the link to his YouTube channel: / @daleeason9687
The software can be downloaded from:
github.com/githubdoe/DFTFringe/releases
This is the link to the interferometry group on DFTfringe that Dale runs:
groups.io/g/Interferometry
The Point Diffraction Interferometer can be purchased for about 50 Euros from Michael Koch at www.astro-electronic.de/
(not sponsored content)
Other videos in this series:
Part 0: Tiny telescope concept video (featuring Rik): • Why is this Space Telescope so Tiny?
Part 1: Optical Design and Aspherics; • Making a Monolithic Telescope Part 1:...
Part 2: Machining Glass; • Making a Monolithic Telescope Part 2:...
Special thanks to Dr. Liam Fullersheit for his guest appearance. (;-).
Views : 250,478
Genre: Science & Technology
Date of upload: Jun 10, 2022 ^^
Rating : 4.969 (84/10,888 LTDR)
RYD date created : 2024-05-02T15:21:18.53868Z
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YouTube Comments - 689 Comments
Top Comments of this video!! :3
Honestly, this video series is perhaps one of the most interesting I've seen the entire time I've been on YouTube. It makes something quite obscure much more accessible.
130 |
It's really great to see everything coming together in the final product. Very cool project! Did you ever find out about the difference in apparent focal length vs designed focal length? Is it possible that the microns of surface adjustment can affect the focal length that much?
503 |
Aww hell yeah! Looking forward to watching this, and thanks for continuing the series!!
85 |
Setting aside your disappointment with wavefront accuracy, I have to say that your presentation and explanation are of the highest quality..! Many folk can grind glass, and perhaps expensive machines can do it more accurately, but very few here on the 'tube surpass your quality of content..!
93 |
Incredibly niche topics explored deeply, with the perfect amount of detailed conceptual explanation. Engineering poetry. Solid state engineer with only a passing interest in optics, yet these are captivating. Thank you for these incredible videos!
46 |
I have an idea how to make the contrast better. I believe a problem with black paint is that it’s not intended to be black to what it’s painted on but rather towards outside observation. This means that some paints rely on their drying process to create a surface structure that helps with absorbing light. It obviously doesn’t do that on the side that’s sticking to the material though. I believe a method that could work well is to use an epoxy resin in which you use something like activated coal as a pigment as this should absorb light very nicely.
I admit I don’t have any experience in this field but I believe this might be worth testing.
137 |
Cheers to you.
I believe the quality may improve when a long black cover cylinder is placed on the lens.
31 |
Love it. My take away seems to be "use a cnc aspheric grinder to reduce masochistic rage"
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I would watch SEVERAL hours of you explaining all of the details. It's fascinating and your explanations are incredible.
10 |
Amazing stuff Zen Master HO!! Some years back, it would take me about 12 hours work to prepare a 1 hour Mechanics Lecture at University. I could not even begin to estimate how much time and effort went to producing this 30 minute masterpiece. I would hazard a guess at weeks....if not months?
Thank you!! Oh - and as fascinating as the field of Optical Physics evidently is - I for one would fear the real possibility of insanity were I to attempt a project requiring this level of precision, patience and mathematical/scientific know-how. IMPRESSIVE STUFF INDEED.
Now get Cracking on that order for 'Sales' 😂😂
12 |
I would consider this to be an excellent result even if it was a 2nd or 3rd attempt, let alone the 1st one. Great job!
28:53 The black spray paint makes the frosted inner surface behave like a reflective diffuser.
I think a less viscous paint would more thoroughly seep into the tiny pits before drying. Spray paint particles might even be too big to properly fill them in (possibly creating a refractive/reflective nightmare of tiny air gaps). A more matte/flat black wouldn't hurt, either.
42 |
wow, wat een geweldig project. Petje af! Dat Pitch Polishing leer ik graag nog eens wat meer over. Lijkt me leuk om eens van dichtbij te zien
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I'm really enjoying this series. It has some close parallels to mmwave dielectric lensing. It's really useful to see how the issues are handled at 600 THz rather than 122 GHz.
5 |
Did i just watch three videos with extremly technical concepts, extremely accurate techniques of all kinds, years worth of experience in order to even begin with, about 200k worth on ultra specialized machinnery, months of planning, hard work, tweeking everything to finally compare the product to a cheap 200usd 300mm lens and find out our thingy sucks? lol
Now for real, i enjoyed every second and loved the whole project.
Congrats!
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Superb! Superb! Thank you! As always, a wonderful journey into the art and science of really interesting optics. The skill and ingenuity on display is an absolute inspiration, and congratulations on even realizing Rick’s challenging but inspired design. As always too I cannot thank you enough for the clear and concise education in your videos, it is second to none. So congratulations and thank you!
25 |
Love the videos Mr huygens,i would have learnt so much from you, had you been my university lecturer,there is so much detail here,you include problems,and are open about mistakes made,This is what education should be like IMO,step by step explanations,with details of problems,as well as progress made,theoretical and practical,beautiful stuff.
Your sense of humour is terrific. i thought you northern europeans were born without the humour gene!!
Anyway,im a firm subscriber. BTW i originally trained as a radio and tv technician when i left school,yonks ago.Your explanation of the analog TV transmission system is spot on..
11 |
This video can be used as lessons in university. Incredible details. Actually never thought how many details and craftmanship are there for making something that looks simple. Bow to you champion :)
2 |
Wow, so fascinating! It was so interesting to me to learn of all the second-order effects that came into play, and the idea of using 3D molds to form the pitch laps was brilliant!
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Incredible work, great video, and the performance from such a small monolithic lens has really impressed me!
4 |
@salmiakki5638
1 year ago
though these videos i'm just drawn to think how much better/faster i would have learned at university if taught through projects like this one. Having to tackle both theoretical and practical/technological problems and solutions in order to achieve a practical goal.
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