I have, actually. There are a couple of designs I've considered. One that doesn't need a flat bigger than the mirror would be good :) But I've been really interested in the Bath Inferometer too. I will likely make one of those, because it seems very cool.
It's a 12.5" x 68.5. just shy of f/5.5. Still working on it, plan to resume in the fall when it gets a little cooler.
Nice image and stable tester that allows you to move the knife position w/out further adjustments.
Bowl or hill? Its cool to play with perception, but if we know which side the knife edge is on, we don't have to guess what we're seeing. Knife on the left = light on the right; knife on the right = light on the left -- IF you're at the center of curvature. If shadows move with the knife, you're inside the radius; if opposite, you're outside the radius. At radius, you need to know the tester.
I don't know if you're using the foucault to make telescope mirrors but I tried doing that and when you start measuring the distances between the different focal lengths through out the radius of the mirror it got so complex that I just gave up! I couldn't get my measurments accurate enough to get a parabolic mirror. I got the mirror down to where I could do 10 minutes of work to get a parabola! I would like to know if you've done this yet! If you have I would like for you to help me out! Thanks
I make a few mirrors myself and I get that flipping between the two images like you said about the craters on the moon looking like little domes. Its nice to see this on a comp screen.
Can you tell how you set the camera up to make this movie ?
JustWonderingHowToDo 2 months ago
@JustWonderingHowToDo I made a little platform big enough to hold my sony camera, where my eye usually is focussing was pretty easy. Zoom helped.
I should do another one of these now that I have resumed my figuring...
tabhorian 2 months ago
@JustWonderingHowToDo Also, you can find out more about Foucault testers here in youtube. Mine is based on the design at the Stellafane website.
tabhorian 2 months ago
I have, actually. There are a couple of designs I've considered. One that doesn't need a flat bigger than the mirror would be good :) But I've been really interested in the Bath Inferometer too. I will likely make one of those, because it seems very cool.
It's a 12.5" x 68.5. just shy of f/5.5. Still working on it, plan to resume in the fall when it gets a little cooler.
tabhorian 2 years ago
Interesting, Have you considered using an autocollimator?
What diameter is your mirror? What is the focal length? How did it turn out eventually?
Best regards,
Francis J. O'Reilly
foreilly1958
foreilly1958 2 years ago
Nice image and stable tester that allows you to move the knife position w/out further adjustments.
Bowl or hill? Its cool to play with perception, but if we know which side the knife edge is on, we don't have to guess what we're seeing. Knife on the left = light on the right; knife on the right = light on the left -- IF you're at the center of curvature. If shadows move with the knife, you're inside the radius; if opposite, you're outside the radius. At radius, you need to know the tester.
vtsolarguy 2 years ago
I don't know if you're using the foucault to make telescope mirrors but I tried doing that and when you start measuring the distances between the different focal lengths through out the radius of the mirror it got so complex that I just gave up! I couldn't get my measurments accurate enough to get a parabolic mirror. I got the mirror down to where I could do 10 minutes of work to get a parabola! I would like to know if you've done this yet! If you have I would like for you to help me out! Thanks
planetman07 3 years ago
I make a few mirrors myself and I get that flipping between the two images like you said about the craters on the moon looking like little domes. Its nice to see this on a comp screen.
malaclyppse 3 years ago