I've been using a 50 micron pinhole from Edmund Optics. I can also add Narrow Band filters to the assembly if I want. I have sometimes used the solar glint off...
Using a 50um artificial star set approx 100feet away from my C11 on Jan 27, 2007 I collected some intra/extra Toucam web data. I opened my observatory up 2hrs...
Hi Steve, ... it ... align, ... my ... right ... I have sometimes also seen this problem where Roddier fails to align the images. It usually results from some...
Couple more thoughts. The 50 micron pinhole at 100 feet is about 0.34 arcseconds. The resolution of the C11 is about 0.36 arcseconds. So pinhole is just...
John, thanks for your feedback. I just posted a screen shot of the wavefront data, although I don't really understand what it means. I totally agree that...
Wavefront map mostly looks like coma (collimation a little off) and various types of spherical on top of that. I think that you are already getting 71% Strehl...
John, My last collimation was done for the first time using http://www.astrogeeks.com/Bliss/MetaGuide/ software which involves real time collimation feedback...
Thanks for posting! The test is sensitive to the actual focal length of the telescope. While a SCT is labeled f/10, IIRC they have longer focal lengths when...
Philip, I just inputted my 2.5x barlowed intra/extra data (7000mm focal length) into the Roddier program and the strehl number increased from 0.71 to 0.85. I...
Hi Group Tomorrow, I am going to take some inside & outside of star focus images using my 132mm WO FLT refractor and SXV-H9 ccd camera and was wondering how...
Hi Chris, I do not have your exact setup, so my advice is only of a general nature. You will want to expose long enough to average-out "seeing" effects --...
... Hi John Thank you very much for the kind words and helpful suggestions. Here is my setup Losmandy G11/Gemini Level 4 goto Starlightxpress SXV-H9 16 bit...
... Hi John I also forgot to mention that my WO FLT refractor has graduated markings on both the focuser drawtube and camera angle adjuster. I will take...
... is ... design. OK, this sounds like a good setup. So I would suggest to take several sub-images maybe 30 or 60 seconds at each focus position. You can...
... Yes, these markings on the drawtube will certainly make things easier. You should end-up with patterns having about the same diameter on the computer...
Hello everybody, I'm trying to get a handle on doing this testing correctly, and then repeatably. The scope I'm testing is a 10" f5.47 with a 1.83" diameter...
Hi Bob, After puzzling over your images for a while, some comments: I think your basic technique is sound. The images seem well exposed without obvious...
Hi John, Thanks for the informative reply. The camera is an Imaging source DBK21af04.as. The CCD is similar (maybe identical) to the ToUcam. This is a RAW...
Interesting report! The use you are putting the Roddier test to is one of the reasons I think it's so exciting. Try the test again on a single star as high...
Bob, Looks like you have the technique well in-hand, and just need some better seeing, and maybe a little collimation work. These seeing "slow waves but very...
Hi Group Last week I tried to take 1 sec, 10 sec, 30 sec and 60 sec images of the star Dubhe from 3mm to 9mm outside & inside of focus using the green filter....
Hi Chris, If I recall you are using a conventional CCD camera in a 132mm scope? Yes, it is likely far over-exposed. I use very bright stars, but I am also...
The Roddier test does not use the classic star testing diffraction ring pattern that we are familiar with from visual star testing. The images are taken much...
Yes, like Philip says, it would be good if you could take lots of short images (<1 second to few seconds) and then stack them up. This also avoids potential...
... Hi Philip and John Thank you very much for the suggestions. I will try a 4 to 5th mag star tonight and take < 1 sec exposures. Philip, I looked at your ...
Chris, Yes, the images are just far over-exposed. There is a fainter star below and right of the bright one, and that shows rings and nice details. That is...
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