Field Flattener for ed100 refractor

[OuterObsession]

I'm wondering how important a field flattener is if I take flat frames? Is the sky-watcher/orion /synta field flattener any decent? Anything else I need to know about field flatteners?

Cheers,
Jameson

[that_guy]

flat frames are there to remove any dust specks or abnormalities in the imaging train and has no affect on the curvature of the image which the flattener does. The ED100 prob could use the flattener as almost all refractors of that focal ratio does.

[OuterObsession]

I thought Flat frames remove vignetting and if you combine that with a lens correction profile in photoshop wouldn't that do something similar to a field flattener or am I missing something?

Also I noticed that a lot of field flatteners reduce the focal length. What if I don't want to reduce the focal length?

[cometcatcher]

I use the Orion field flattener (available from Bintel) on my ED100 and it doesn't reduce focal length.

[Chapstick]

I am using https://explorescientificusa.com/collections/flatteners/products/2-field-flattener-lens-for-ed-apo-s on my ES102

[OuterObsession]

Yeah I saw that one but this line made me worry I wouldn't get good results as the ed100 is f9 "Designed for use with refractors with focal lengths of 400mm to 660mm and focal ratios of f/5 to f/7.5"

But I've heard from some that it still provides some correction a little bit outside of the range.

[cometcatcher]

It sure does. Takes away the central hot spot too.

[OuterObsession]

Hmm know I'm just wondering which one would be better overall.

The one designed for the ed100 but reduces the focal length or the one that isn't designed for the ed100 but doesn't reduce the focal length.

I'm curious if anyone has tried both?

[cometcatcher]

I also have an Orion 0.8x reducer that I used to use on the ED100. Works well. I think you will find the ED100 is a very forgiving scope with just about anything you put on it.