How to Make a Pitch lap and Polish a telescope mirror!
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- เผยแพร่เมื่อ 5 มิ.ย. 2024
- In this video I continue my DIY How to series on Making a telescope mirror! In this part i am Polishing the mirror and showing you how to make a Pitch lap!
- วิทยาศาสตร์และเทคโนโลยี
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I have found two videos that explain clearly and clean how to make a pitch lap. One is from a retired optician, the other is your video. Congratulations, great job. Still learning and teaching to all of us.
Thank you very much! I am glad to hear that!
That is a superb explanation of how to make a pitch lap. Probably the best kept secret in astronomy. Thankyou from the UK (where it's still raining).
bro, as no comment of appreciation can be worthy enough, there is nothing to say...
plz complete the series of finishing a diy telescope...
Riveting series of videos!
You are brilliant, well spoken and teach in a way that all can understand.
You will go far in life!
I've taken this project up for my Physics Honours. This video really helped me understand more about the process. Thanks a lot!!
This was absolutely fascinating. I'm dying to watch part 4.
Thank you so much!
thank you for these videos. The more I watch the more confidence I get and I know for sure I'm gonna make my own mirror one day.
Thanks, that means a lot!
I had a book about telescope mirror polishing as a kid! Never got around to making one (we didn't have either the space or the money). It's cool that people are still making these by hand, even though the availability of cheap commercial mirrors has kind of taken the "need" out of the equation.
Thank you for demonstrating the reflector telescope mirror making processing. looking forward to the part 4 -- "figuring" . Appreciate your explanation and the reasons behind each steps
Thanks Douglas. Have been waiting to receive a new mirror blank for part 4, as this mirror having such a long focal ratio didn't tell you much about how to figure the mirror!
Cheers
i loved this video! I am an optician and loved every second of it! Im about to steal some supplies and start making my own teehee
Thanks! That's awesome, good luck on that!
Wow, great video. I've always wondered how this was done and you did an fantastic job explaining it.
Very well spoken. I enjoyed your presentation. Please use your skills to teach everyone !
Thank you!
thanks, great work, greetings from Ecuador
I like your all video 🙏🏻❤️
Great video! Really nice.
Nicely explained details!
Great work Logan.
All the best for all your endeavors.
Thanks!
AWSOME! That was a cool video thankyou
Thanks so much!
Do you know what they used in the old days? They didn't have cerium oxide in the 1600s, and spectacle lenses go back even further.
Just finished watching all 3 of these videos in this series and they have been very informative. I have been considering making my first mirror so soaking in as much information about it as I can. I see you put these three videos out in April, wondering if you have the follow up video(s) to this series? Also, where do you usually send out the final mirror for the coating? Great videos, and look forward to seeing more!
Hi, Thanks! At the moment I don't have anything ready to put up on following up on this, as this mirror was finished way too quickly for anything useful to come out of it. Hopefully some time in the future i plan on finishing this up. I usually send my mirrors away to someone from my astronomy club who has facilities for coating. Cheers!
When is part 4? How do you ensure the aluminizing process will work? Great video BTW.
Great video! Liked and subscribed and looking forward to watching more.
Awesome, thank you!
Free noise reduction apps or software would have solved the wind problem fifteen minute in. Good demo still Thanks
Thanks for the suggestion! Will try and avoid problems like that in the future in the first place hopefully :)
Could silicon be used instead of pitch? Thanks for the posts, very informative.
Hey man this is amazing, I'm 16 and about to do my first mirror (8" f/6). Are you ever going to finish the series? It is really good
I will watch the video well.
Have a nice day .. ^^ ~
Is it ok doing optical polish in the open? It needs constant temperature and dust free environment or you did it just for filming the procedure?
Hey, I found these videos inspiring. Why didn't you create part 4? Is it cost, moved on, etc?
These are effective but the main issue is to get them layered after wich is quite much harder nowdays since people basically dont do crafts as much as they once did...so a premade dobson mirror or an optic tube even will be both cheaper and easier. Optic tubes nowdays are much cheaper than they were
Yes that is very true. Economically it doesn't make much sense because of the aluminizing process, but for bigger mirrors it can pay off. But it's also good fun!
Good bro
Great videos Logan! I'm hoping to start my first mirror in the coming months. Curious to know what size this mirror is you're working on? Also I feel like I've always heard that the tool should be the same size as the mirror, is this a different technique?
Hi, the mirror size is 8". The tool is smaller but i would probably reccommend using the same size tool for starting out. A smaller tool can give you more control over the mirror surface when figuring. Cheers!
I'm planning on tackling this process myself but can't find affordable glass anywhere.
Wow! Not sure if this channel is still active? Just a question, if we to use a blank mirror, how to determine the pitch curvature?
Should we give it a extra mirror coating on it? Or is it just like it is. What i mean is how will it act as a mirror while its a just a "shaped" glass, i can just use a concave lens i this case .
Pls reply fast, I'm confused 😥
Hi, this serie is really great. This one of the best source i found to create mirrors !! Just a quick question though, will the mirror be parabolical or spherical (or something else) ?? Thank you very much !
Thanks! At the end of polishing the mirror will be roughly spherical, and after figuring it will be a parabola. Cheers!
Me also bro. This series is really helpful
Hello, super super random question, but it seems like you really know what you’re talking about!
Question: im making a pitch drop experiment with gugolz #55. I’m using 55 because from what I understand it is the softest pitch they sell. But from a previous persons experience, the #55 was still too thick/hard. He suggested I thin the pitch but neither of us knew how. He suggested astronomy forums since you guys are familiar with pitch.
Would you have any advice on how to thin pitch? I would greatly appreciate it!
Hey there. You got yourself a sub. I hope to make one of these, as I believe some steps can be alleviated with recourse to some electrical tools. Also, any reason why the glass is so thick? From the grinding, and convex arc, wouldn't a thinner glass suffice? You know... Prices...
I fail to comprehend when are the glass becomes mirror. Will you happen to follow this up, or is it a dead preject?
Very well laid out, and a very welcoming change of pace from other content creators. Your videos are calm, no fanfare. Good job, and I hope to see a notification soon.
In case you are still wondering:
The glass has to be this thick in order to not deform under its own weight, i.e it needs to be rigid to stay very accurately curved. The easiest way to do this is by making it thick.
There are ultralight mirrors but those are usually contained in very special mirror cells, are more expensive due to a different kind of glass being used, are not flat-back and are thus much more susceptible to warping due to temperature changes. This will end your observing session immediately if you have no way to cool the mirror without inducing air turbulences.
heres the basic process of making the actual mirror surface.
There are 2 ways to achieve this. One is Silvering and the other one is Aluminizing. You can only do Silvering at home. Aluminizing is a whole different level and cant be done at home, at least not without extensive knowledge, precision and hundreds of thousands of dollars worth in machines.
What you want to do is Silvering. Basically you spray or pour 2 solutions on to the polished mirror blank in precise equal amounts and it becomes metallic silver depositing on the surface. These solutions consist of: Distilled water, Silver nitrate and Ammonia.
Once this is done, you rinse the mirror with distilled water and then put on a protective coating to let the silver "dry" without clouding or spotting up, in which case you have to strip the mirror using ferric chloride and start again. The protective layer is kind of a secret sauce as im not able to find anything on it.
This is an expensive and potentially dangerous process. The cheapest possible way to do this is by having background knowlege about chemicals and having a cheap high quality supplier (stay away from sigma-aldrich please...). The second cheapest would be the spray silvering kit from "angelgilding dot com" (not advertising, just the only thing i could find)
They also have a short series on how this process is done here on youtube.
@@Sharpless2 Thank you very much. Appreciate it.
What is the pitch made of?
I couldn't understand the word you used.
"Acular?"
Nice video!
How much CeO2 did it take to polish the mirror?
Hi Julius, it took me about a spoonful or less, using the squeeze bottle method it is pretty hard to run out of even one spoonful! Cheers.
Could you make a video on how to figure a mirror?
Great work. There is a lot of satisfaction to be gained from making your own equipment. Too much work for me though.
Thanks! Definitely something to try one day!
Did you succeed in figuring?
I'm still confused how you got the curvature that you desired. Is the tool angled or flat?
I’m pretty sure that the mirrors’ shape is determined during grinding, and the lap takes on that shape when it is pressed into the mirror.
Both start off flat. As you grind down through the grits, the top disc naturally takes on a concave shape and the bottom becomes convex. It does this because at the ends of the grinding strokes the disc on top overhangs the disc on the bottom resulting in more pressure and therefore more grinding action in the centre of the top disc and conversely more grinding on the edge of the bottom disc.
How much did it cost for you to get the mirror blank? This is a project that I've been looking into but I want to be budget-conscious too :)
www.telescopemirrorblanks.com/mirror_blanks.html :-) Prices are quite reasonable. Of course you can get a polished and metalized mirror from China for not much more than the cost of materials... so unless you think that you can make a better mirror (or a different one!) than the Chinese optical fabricators... but that's the tragedy of affluenza... everything is so easy, today. You just buy it from somebody for next to nothing.
How hard is Acculap?
When are yoy giving aways? 😅
Pl explain which resin is pitch?
Hi, the one I use is called Acculap, it's pretty much a synthetic sort of tar. Thanks
R pitch and resin same?
Very similar, In action yes
Dear brother I want to make a telescope. But, I have no idea about mirror cutting.
I would be very grateful if you could give me a list of mirror cutting materials in writing
Hi, thanks for the interest! I think if you read stellafane.org/tm/atm/mirror-general/materials.html this may give you a direction. Cheers!
What is pitch lap materil
Hi, It is Acculap. Google search should show suppliers. Good luck!
Love the video, get ride of the music
Thanks for the suggestion.
Why does the thumbnail look like a piece of steak hahah