TELESCOPE MIRROR MAKING HOW TO: Fine Grinding
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- เผยแพร่เมื่อ 4 มิ.ย. 2024
- In this video I am showing you how to make a DIY telescope mirror! This is the second part in the series, showing fine grinding in a step by step tutorial.
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I will probably never in my life make a telescope but I now know how. Thanks Logan!
Something to note is that you donlt want the difference in diameter of tool and mirror to be too big, makes it easier to keep things uniform.
Weight distribution is what makes the curve. A centered tool that's bigger than the glass will just make a flat surface. If the tool is smaller than the glass and center of mass of the tool is over the glass, it will hollow it out, and if the center of mass is outside the glass, it will round it convex
Best tutorial Iv found yet ! Great job
these instructions are the best. Way to go
Another awesome upload!
This is an excellent tutorial. Thanks for taking the time to put it together!
Thank you! That means a lot to me!
Love the chalkboard!
Great to watch you grinding 👍 keep it up 👊
Truly great video
Wow superb video ❤️❤️❤️ thank you for sharing 🙏❤️...👍👍👍
Thank you very much, glad you liked it!
Good luck young man, I believe you'll achieve your goal.
Logan, I have a question ... I'm a bit confused ... How do you get the exact amount of concave (1/8" depression) to be perfectly equal all around the mirror? I don't see how this is achieved - Does the difference in size between the tool vs the mirror blank make this process automatic? Obviously I'm a beginner and sorry if my questions sound dumb ... Just seems to me that the process never checks to see if the depression (concave) in the glass is perfectly equal or at what depth. BTW, I think you are an excellent teacher way, WAY beyond your years - Someone will be very lucky when they hire you. Thanks-
with this method it is impossible to get a perfect concave surface, however you will get a plenty good enought surface for amateur astronomy. there are other videos of optical lens grinding outhere that use some fine equipment to check the work for defects. the grinding is mostly the same, just pitch and the grit, though they use a variety of tachinques to achive an optimal lambda result.
Is the grinding tool flat or does it have radius? And do you measure the radius of the mirror during grinding? I saw you taking measurement of the centre depth in pt1 (once), is that enough?
Awesome video dude!!!
Thanks!!
Thanks for the awesome videos. I only make small telescope models and need small (probably plastic or aluminium) mirrors
Thanks! Nice, hopefully that turns out well for you!
@@AustralianAstronomy thanks :)
@Allen Loser thanks Ill deffinitelly look into that
Logan, your presentation is fuckin awesome mate. Very well done
Cheers!
Wow! How do you get a consistent shape to the curve of the mirror when doing it by hand??
Yeah, I was about to ask the same question.
Just wondering how long it took you, in total, to grind and polish the mirror?
u learn and teach every thing in detail , these are the quality of an expert, but can i know that what is the cost of making this mirror in total
Thank you very much! The cost is very difficult to answer as it varies from place to place. I recommend asking local astronomy groups to try and find a better price. Thanks!
There's this guy in NZ asking 2400 for a 25 inch blank. Would you say that's a crazy price?
Great videos btw. I'm trying to watch them all.
Thank you for all your effort.
Hi, I think I might have talked to the same guy at some point. That seems pretty cheap for what it is IMO!
@Allen Loser how would that be done?
How do you know you’ve ground the surface into a parabolic shape? To what degree of precision does the mirror follow a parabola?
I came to find out what the tool used to work the glass was made from, sadly, not in this video. Looks like ceramic?
Hello aust.ast. greetings from India. You described very nicely, actually I wanna make an objective primary of 8inches. You helped me lot. Problem is what I can't find different grit powders to rough grinding. Any alternative solution?
I will be waiting for your kind reply.
Hi Bunty, sorry for the late reply. If you have a local astronomy club you may be able to ask someone there. For rough grinding you might be able to use diamond grind wheels by hand to create the curve. Cheers!
Industrial supplies. sand blasting companies will have the coarser grits to get you started.
There may be something in this one that helps as well.
th-cam.com/video/P_u9zjamBvs/w-d-xo.html
Does the tool grind itself down to a flat contour? The tiles seemed to be arranged quite bumpily at first.
Hi, thanks for the question! The tool forms a regular shape with respect to the mirror over time thanks to the constant rotation of both the tool and mirror
Its kinda spooky but true that whenever you rub two flat glass slabs against each other, one kept on the table, they tend to become completely parabolic in shape by grinding. Hail Physics !
Good video
Thanks!
You never stated. Is the grinding wheel with the ceramic glued to angled in any way or just flat?
You try to make it pretty flat. The curvature will be worn into it at the same time as you make your mirrors
spin-cast epoxy directly into parabolic mirror mold
did you make a spherical mirror or a parabolic ?
Spherical. Making a parabolic or hyperboloid mirror is much more involved, and a spherical mirror will do just fine for getting started.
1:10 by volume or weight?
Hi, the drawing is just a rough explanation. Cheers
How to aluminized
the question is, where to get the mirror?
Hi, you can order them online from various suppliers, or you could find a local astronomy club.