Group - I have completed a series of Roddier tests on my C6R and have posted some data files, results, and discussion to the Files section in the folder...
Mick, Thanks for posting your results. So far I just had a very quick look at them. Here's a first pass at your questions. Perhaps others will add from...
... Mr. Biretta - thanks much for the "quick" response and answers to my questions; seems pretty well thought out to me. If you get a chance to look a little...
Hi guys, I just uploaded tifs for extra/intra focus for my C9.25 in the files dir. They are tifs stacked with registax using a toucam. The seeing wasn't that...
All right then! Good news, your scope is diffraction limited. The numbers I git out of the run are: RMS: 1/13.9 PTV: 1/2.1 (Ignore this one, PTV is almost...
The Roddier test is sensitive to focal length, and if the camera position of the Toucam had the C925 operating at, say, f/12 (2820mm), the RMS becomes 1/16.6...
Thanks for the results, looks like I barely squeak by diffraction limited. The color of the star was blueish..but I think there might be a white balance issue...
I did a query out to see what focal length a SCT operates for prime focus, such as when a Toucam with no diagonal is attached, and it seems it's pretty much...
Just learned of this tool on another forum and don't know much about it. I am intrigued by the prospects, but after looking through some of the archived...
Hi Kevin, The Strehl ratio is the ratio between the amount of light in the Airy disk for the scope and "some other number." Usually the other number is the...
Thanks John, you've been most helpful. I see in looking at the examples and tests that the software is in French. Is there a page with some translations or...
Hi Kevin, Some answers below.... ... No, we do not have an english version of the software. The Cookbook in the Files section is in english, however, and...
This is fantastic news! New version 2.0 is much more user-friendly with regard to setting thresholds and aligning the images. This is an area where people...
Good news. I did hear back from the programmer Lequevre who will try to join us here. And he mentions he is interested to make an english version also. I...
I'm interested in seeing some good data on SCT quality particularly the Celestrons. Also John B. I saw one of your old posts about testing a c14. I'm ...
Hi Greg, ... There are a few tests on Celestrons in the files area. My impression so far is that most have good glass. Though typically we see several...
Well let me know when you want to have a group chat. I would announce you. You probably don't need it. But we have enough people with web cams that we...
I'm familiar with that article. I really do wonder if all the 9.25s are that poor! After rotating the correctors they got Strehls of .83 and .88, but they...
I suspect this (i.e. 0.92 strehl isn't 1/4 wave) is more along the lines of not understanding how an optic is measured and what it means! With the rise of...
Numbers for the SCT tested here so far (converted to Strehl using ((RMS * 2 * pi) 2 -/+ ) Inv Nat Log): C11 - either 0.71 or 0.85 C8 - 0.88 C11 - 0.87 C14 -...
How could the c14 be "above" the theoretical Strehl limit? I'm still not understanding whether we are comparing "the sct to a perfectly executed theoretical...
We are using the Strehl ratio not compared to a perfect unobstructed telescope, but to a perfect telescope that has the same obstruction size as the one under...
We do need more scopes that have been interferometrically tested in order to gain more confidence with the limitations and applicability of the Roddier test....
Personal opinion here but I think that's a confusing way to do it that people are likely to take out of context. Obstruction percentages vary. To compare...
Or at least to have some term that will disambiguate. For example, "strehl-to-design" vs "strehl to unobstructed" but I guess that's not good because...
Having problems with message search?
Fill out this form to ensure your group is one of the first to be migrated to the new message search system.
