I've had the Meade series 5000 ED80 APO triplet (f6) for a few years but have never really used it much for astrophotography. It has a reasonably flat field but there is a bit of coma at the edges. I'm wondering what flattener would be best for it?
I wonder if anyone has tried it on the 80mm? I found in the archives mentions from Zuts of this scope needing a flattener but it doesn't say what type he was using.
I ended up purchasing the Orion after trying Troy's one with the artificial star. I also made a custom adjustable spacer and have been playing with the spacing. Here's a test image from Thursday night showing the four corners at what I think is the optimum spacing. The whole flattener/spacer/camera assembly is almost as long as the OTA now and I'm wondering if the stock focuser is up to the task - thinking I might need to upgrade to a Moonlite.
That looks really excellent Peter, flat to the edges and you can't ask more than that. That ed80 certainly was a good buy and make sure you treat it to a RED moonlight!