Hi, Can I use the USB camera that came with a Meade AZ70-A to take pictures of a defocused star on a CPC1100 and to do startesting? Images inside and outside...
Hi Mike, Welcome aboard! It likely that your USB camarea can be used. The brightness scale needs to be linear to get accurate results, and not all cameras...
Group - back in Dec 07 I posted some results from Roddier tests on my Celestron (Synta) C6R using an artificial star as the source; see post #276 and the...
Mick, Thanks for posting the results. They seem very nicely done and well-documented! Testing a scope with this much chromatic aberration is certainly a...
... Mr. Biretta - thanks for the kind words about the C6R tests and even more thanks for taking the time to examine and critique them. My main "hidden"...
Hi Mick, Thanks for the picture of the focuser collimation blocks. Very clever! I sometimes have put small plastic or tape shims between the focuser mount and...
... Mr. Biretta - thanks profoundly for the very complete and detailed reply; almost makes me want to try to learn how to use Aberrator. The collimation...
Bits, A/D, D/A and Signal to noise ratio. This is something which I have studied, albeit long ago. The only, repeat, ONLY thing more bits in an A/D (Analog to...
Philip, Thanks for the interesting discussion on bit levels. I personally still wonder how the 1 bit sampling on audio CD players works.... Will have to look...
Hi I am new to the group. The attached file do not seem to load into the program. Could some one please tell me what is wrong with them. The files are for a...
Roddier program is very particular about which flavor of FITS you give it. I reformatted the images in K3CCD and FV, and put them in Files/Walker. Seems like...
Thanks for the help. The files load now but I am still having some problems. I will e-mail "zeissnut" directly. For general interest: I am working with a Canon...
Hello Scott, Great that you are trying using new types of equipment for getting the data for a Roddier test. One of the most important items for this test is...
... Dr. Biretta - I do plan to give the experiment a try. I will make a mask that fits snugly inside the outer part of the lens cell and will drop the clear...
Scott, I am using the "old" version Beta 0.4 of Roddier. It all runs fine for me. I put the results in that same folder. Are you using the newest version? I...
I tried the new version 2.0 on your images, and it also seems to work fine. Result is slightly different -- 0.982 Strehl instead of 0.99 Strehl in old version...
Thanks for the help. The scope is a Williams Optics ZS80FD. It is a well corrected doublet. The test source is a green led centered at about 525nm. I think the...
This is sequence of steps I am using with newer version 2.0 of the software: Ficher > Nouveau test Ficher > Ouvrir l'images intrafocale Ficher > Ouvrir...
Thank you very much for the help. I was missing step. It now works fine. ... From: "zeissnut" <grzincic@...> To: <roddier@yahoogroups.com> Sent: Monday,...
I can try to give a very brief explanation. The optical aberrations of a telescope make various changes in the brightness patterns seen in the out-of-focus...
Very clearly writen. Thanks John. Scott Walker ... From: "zeissnut" <grzincic@...> To: <roddier@yahoogroups.com> Sent: Tuesday, March 18, 2008 7:50 AM ...
I have been working with the Roddier program for the last week. I am testing with a Canon 350 Rebel camera and an artificial star at a distance of 14.3meters....
Scott, Very interesting work. We need more tests of this nature. ... am testing with a Canon 350 Rebel camera and an artificial star at a distance of...
Thanks for the comments John. As far as RMS and PV are concerned I was trying to do the following, but did not explain: For lens testing the RMS waveform error...
While I am very grateful to John for the Cookbook, has any better way to prepare FIT files for Roddier tests emerged? And what exactly does K3CCDTools do with...
Hi Dmitri, I have also had some success using the "Nebulosity" program from stark-labs.com. It costs $45. You just read in the Registax image, perhaps crop if...
John, Nebulosity works very well for Roddier. All I have to do is to open the raw file in PS, make a square crop and save as 16-bit TIFF with any compression...
Hi Dmitri, Thanks for info. Yes, I think in the end Nebulosity may be easier way to go. There are less steps than K3CCD and FV. Steps are something like...
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