Thanks Mike, if it's astigmatism (must confess I haven't star tested these optics yet) do you think it would have a differential impact depending on where you put the guide star?. I'm curious as to how this could impact guiding though. The star resolves to a point?
cheers,
Rob
Quote:
Originally Posted by ozstockman
Hi Rob,
I gave you a link in your previous post about WO flattener and vignetting which exactly describes your problem. Moreover it's about the same scope your are using. It does not happen because your guiding is bad it happens because this scope has astigmatism. I have the same with my ED80 which is a clone of WO ZS80.
If you add a barlow it wont fix problem but you'll make your guidescope much slower(f/11.5 if you add 2x barlow). It means that you'll have to increase exposure time to pick up the same star. It also means that PHD will send commands to correct your mount less frequently.
cheers,
Mike
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