Swapping out the focuser if you already have one and getting rid of the CAA would be a definite first step. Then the optics can be analysed more
accurately.
There is another thread on CN where a guy had an FSQ with some chromatic aberrations in the corners and sent it back only to be told the scope was per spec by Tak.
If you look at the spot sizes graph for the FSQ stars do get a fair bit larger further out.
But as images from Mike Sidonio have shown the FSQ can do great all the way out to the corners.
The FSQ106EDX111 I had gave round stars to the corners of a 9 micron 16803 sensor which is several times the size of your 683 and 50% larger than the ASI6200 but with larger pixels.
Greg.
Quote:
Originally Posted by Ryderscope
Thanks Greg, yep - I'm fine with the fact that the OTA should have a flat field at 178mm backfocus which is consistent with my observations thus far. This is why I was a surprised to see such an obvious radial pattern in the field.
From my review of the images, the radial pattern to me looks to be too consistent in the corners to blame tilt at this point. I am happy to be proved wrong of course. I even used the Dynamic PSF tool in Pixinsight to measure the ratio of x/y coordinates of the stars in the corners and they all looked to be the same to me.
Having said that, when I bought this scope I had in the back of my mind that I wouldn't be surprised if I finished up changing the stock focuser as I have been down this path with my TSA120. I fought with that scope for 18 months before finally buying a Feather Touch focuser for it and I have never looked back. I would really want to be sure that the optics are up to scratch first though before spending that sort of money on this one.
I do have a spare Moonlight focuser sitting around that I might try. I would just have to buy the adapter from them to match the FSQ. Would be a cheaper option to check it before taking the plunge.
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