Dave. I would suggest that you not pass up the thrill of looking at the sky with a mirror made by your own hand. Rather than asking someone else to parabolize...
Jerry, Thanks much for your input, I appreciate it. In theory, I feel as you do, and I would like nothing better than to go down to the workshop for however...
Dave. I'm not even saying to put a sphere on it. I'm saying use it as is what ever shape it is. Don't even test it to see what shape it is. See if you can tell...
I have uploaded into the Files section Dale Eason\Focault\Foucault_edge_sim_improvements.jpg I am now getting better foucault simulations from my Igram data. ...
The main reason I post photos to the files section is that on most Yahoo groups only the owner of the picture can see a photo in the photo section in full...
I would figure the mirror for Dave if he used it first. I don't want to cheat him out of viewing the sky with a mirror made by his hand. That would also cover...
... Actually, an 8" f/5 paraboloid has a radius of curvature at the edge of about 80.3"; one might think, then, that figuring would at least change it that...
hm^2/2R For an 8" hm^2 = 4^2 = 16 2R for the f:5 = 160 16/160 = .1 and fl change is half of that = .05" I think... I trust your math more than mine... Where...
... The curvature at the zone, y, for a conic is: c / sqrt^3( 1 + (1-q)*(c*y)^2 ) (My guess is that you are not using this monstrosity.) For a paraboloid, q=0:...
I'm not using that monstrosity. I was doing it in my head the easy way. What I was doing was getting the knife movement which is change in ROC of a zone (in...
Maybe not what I thought last night. In an attempt to confirm I had a correlation with actual Foucault images of the edge, I tried the data from an earlier...
Hi guys, Looks like I need to clarify a couple things or three . . . I'm sorry if I didn't state things more clearly in the beginning. 1.) I have done no work...
Well sorry about that Dave. I guess I was the one who turned having an 8" f:5 spherical mirrror into your having made it. Heee heee, it's my fault Jerry...
Hi Dave, You can download an Excel spreadsheet here that you can use to easily explore what size diagonal mirror and focuser you need to get a fully ...
Mark, I know it is tempting to try to analyze the fringes visually however it is risky to do that. Tilts and defocus effect the way fringes bend with Igrams...
Hi Tom! Thanks for the info. That's a pretty nice Excel app. I do wish it were in inches, and even moreso, it would be great if I could plug in "fixed" (i.e....
While we're on the subject, I have a web page on my web site (www.bill-lee.biz) that will calculate the magnitude dropoff from a sub-sized diagonal (i.e. the...
I needed a second quantitative measurement of the turned edge on my 16 inch mirror that I have measured with the interferometer. I also have what I call a high...
Hi Dale, Thanks for the heads-up. It's unlikely I'll be reading the interferometry group much until I actually get into doing that stuff. But I've had a look...
Thanks Mark, I'm more concerned about being able to quantify the error than the condition of the mirror. I also want to figure out if you can get accurate data...
Greetings, I have finally finished a grinding machine kinda a mirror-o-matic only I made a few size changes to suit my needs and some other modifications. I am...
... month ... Hi Mark, I assume since you are asking this question that you got to 95 micron by doing hand work. If not did this setup work OK up until now?...
Mark I did not read your earlyer writing, but I understand from your swapping TOT-MOT that you have arrived at your Sagitta goal and what you are doing now is...
Wed Sept 19, 8:00PM KPBS-15 San Diego: "Seeing in the Dark" - The growing field of amateur astronomy (60 mins). Repeats Fri, Sat, Sun, 9/21 9/22, 9/23 at...
Hi all, it seems russian AA, optician and telescope maker Valeriy Korneev developed a new (presumably) scheme of fast, flat field all-spherical astrograph. You...
