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Old 28-06-2020, 10:41 AM
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Camelopardalis (Dunk)
Drifting from the pole

Camelopardalis is offline
 
Join Date: Feb 2013
Location: Brisbane
Posts: 5,467
Quote:
Originally Posted by FrancoRodriguez View Post
I'd like to quickly say a couple of things. I've got an esprit 100. It's great in the centre, with excellent colour correction but I found it lacking in the corners for astrophotography on an APS-C sensor. The stars are very slightly elongated. This bugs me no end and I'm getting an FSQ106 for this reason. The esprits aren't as flat as they say. Pretty flat, but it was a slight disappointment for me.
Secondly... ED glass is relatively soft (not as much as true fluorite I'm told) and not corrosion resistant, or at least the multicoating isn't. Even a bit of inevitable bug juice marked up me front end glass slightly. I'm sure salt mist will also. It's not a biggie and doesn't affect the image at all. Just a cosmetic issue. But yes...if I lived 250m from an ocean I wouldn't get an open reflector either.
I suspect you have something wrong with your flattener or sensor spacing then, because I use a Canon 6D (full frame) with my Esprit 100 and the stretchy stars are only barely visible in the last 100 or so pixels in the corner.

It's not for me to critique your purchasing power and choices, but I would say that an FSQ106 is a lot of coin and you might have been better served by asking why your Esprit was not working "as advertised"
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