We have 160 nm to go so I think this is a safe move. ... Hello James, I called this morning but the machine answered again. I'm sure it must be like Santa's...
... Dale The density and contrast of shadows for a given amount of aberration is related directly to the F# and the slit or pinhole width. An F10 light cone ...
Mark, My simulations don't show this effect, so I'm wondering if it is really so for smallish aberrations done near paraxial focus in a null setup. I tried a...
Mark, I have not studied human eye physiology. But from my photography days I think I remember that the eye has a very wide range as well as auto adjusting to...
... the ... My dad told me that wouldn't be part of the part #, But if it is just say, and thanks in advance for copying that guide. I'd apreciate it any time...
... Steve As the eye has the ability to see a lot more contrast range, the visibility of faint zones is not that intrinsically too different between differing ...
Mitchell, doin't worry about the new pits that come about. They are just going to bd shallow pits that are going to be ground out by the next size of grit....
At 10:54 AM 12/2/2004, you wrote: Dave, ... I think 256 grey scale does do pretty good justice to the human eye. I've heard that even 64 grey scale leaves not...
... Hi Mitch and welcome. I have been watching your thread and don't see all of your questions answered so I will try. I built the same tester as you. I...
... Hi Mitch and welcome. I have been watching your thread and don't see all of your questions answered so I will try. I built the same tester as you. I...
... Sorry about that. We a lot of machines running so sometimes we don't hear the phone. ... I'll be sure to take some. ... We're a little better than 1/2 wave...
Dave: Sorry it took so long to get back to you. ... I think you may have trouble working in the garage. If you can move to the basement where the temp is more...
Mark, I think I understand you now. I will uploaded two simulated images. Each mirror has been given the same aberration. In this case I set the Zernike #8...
Dale I've had a look at your simulations. I don't understand the results though . The knife edge results should be `oblivious' of what your primary aperture...
Dale This foucaultgram simulation is definitely of a higher order SA not 3rd order ( which would look simply like a donut or mexican hat depending on whether...
Hi Mitch, You only need one battery holder, one that holds 2 batteries so you end up with 3 volts. I haven't been able to work on copying the Ronchi handout...
Hi, thank you very much. To answer your questions, I am using a 6 inch kit from New port glass with a plate glass tool with grooves, I am shooting for f/8....
... ? ... depth of ... computer ... what the ... I was wondering the same thing.The image of the 20 inch f/5 mirror is way too dark, deep for 1/20. Ric...
... One common mistake in visualization simulations is to ignore gamma. Monitors do not have a linear response. Instead it is better approximated by an...
Mark, ... I was totally wrong. It turns out I had a bug in my program that only showed up if I tried to use the same screen test (e.g., knife test) with a...
Jeff, As you say, this is a hard problem to solve in displaying image with a large range of intensity on a computer screen. I would like to look into this ...
... going to bd ... grit. The ... Another IMPORTANT thing to check is if you are SPHERICAL before you move on. If you are not SPHERICAL, it will take a much...
Hi All: On my second scope now. First was a 6 inch f/8 done from the old ATM books from Scientific American back in 1943. Now I have an 8 inch f/7 I did a...
I woke up too early on tuesday morning: about 3:15am i took a look outside and saw it was clear and there was good seeing so I decided to do a bit of early...
Already seen the sharpie test on gotgrit.com. I ususally mark the center with a pencil and see how fast that grinds of to test for contact. Now I'll just use a...
... As a starting point, Maksutov states that for the human eye to discern contrast differences (within the optimum surface brightness range for the eye)...you...
... Mitch, You are interested in how well the 2 disks match. Make a set of radial marks from the center to edge. With the disks dry and no water, make a couple...
