2024年9月17日 · Home built spherometer - posted in ATM, Optics and DIY Forum: I needed a very accurate spherometer for the secondary that Ive been struggling with. In any event, they are quite expensive. So, I purchased a .01mm resolution Mititoyo domed head micrometer, some aluminum, and fired up the trusty old Atlas 10 lathe. The micrometer head claims to have a +/- …

2024年1月5日 · As mentioned above, contact surfaces of the test optic and the spherometer must be properly cleaned prior to testing. Sapphire, ruby, ets. ball contacts are usually super polished and spherical. Industrially, they are used in machinist feelers. If you use metal ball contacts, they should be stainless steel, precision spheres.

2015年2月23日 · This will require a simple foucault tester, a much more important tool to a mirror maker than a spherometer. Making a spherometer that will provide accurate measurements requires carefull machining practices and access to a high accuracy surface flat or a sphere of known diameter, to determine the datum.

2008年1月9日 · The ideal Spherometer has a four inch hole circle. With the balls at that diameter, one need only take the inverse of the reading and there is the depth of the sagitta! Dave gave me that idea once when he was coaching me on the use of Spherometers.

2007年8月25日 · A spherometer with a 2.8284" circle has a radius of 1.4142, or SQR(2). For this spherometer, R = 2/2s = 1/s, so the radius is the reciprocal of the sag. But for deeper spheres, like Maksutov shells or lenses, you can't ignore the sag or ball feet and you have to …

2017年12月17日 · 4) Calibration of a finished spherometer is necessary before generating sag tables. I calibrate my spherometers using several existing CC or CX mirrors or test plates having radii optically measured to <0.1% accuracy, solve the spherometer equation for the spherometer radius for each, then average the calculated radii.

2011年7月7日 · Just curious, what reading do you get with your other spherometer (the one with ballpoint pen legs)? Perhaps you should borrow someone else's spherometer or make a two-leg bar spherometer and compare the results. Also, use steel wire to physically measure the ROC. If all these agree then the problem is in your spherometer.

2019年3月10日 · How to make a $2 spherometer: - posted in ATM, Optics and DIY Forum: Background: Measuring the central depth does not tell us if a curve is spherical or where it deviates high and low. Holding a gauge along side a ruler over the curve and sampling multiple places and doing the math at each radius seems a bit tedious if doable. There is an easy way I …

2019年2月12日 · Page 1 of 2 - Spherometer calc? - posted in ATM, Optics and DIY Forum: Hello I just received a spherometer from Surplusshed. Works fine - except for the calculation of the radius of the sphere. Accoridng to the manual and web search the formula is: L^2 H ---- + --- 6H 2 Where L is the average distance between the legs (in thi...

2023年12月14日 · DIY Digital Spherometer Suggestions - posted in ATM, Optics and DIY Forum: For all you mirror/lens makers: I am designing/making a digital spherometer, and before I wrap it up (enclose electronics in a 3D case), I thought I’d ask for some feature suggestions from the community. I am attaching some pics of work in progress below. The SAG measurement is …