What is Reddit's opinion of Orion 8893 Field Flattener for Short Refractors?

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Hi, thanks. I needed to remove the 1.25" eyepiece adapter to slide in the field flattener. That is now safely on the telescope. Still the T ring does not thread into the field flattener.

I have this T ring https://www.amazon.com/gp/aw/d/B0114CGRP4

And this field flattener

https://www.amazon.com/Orion-8893-Field-Flattener-Refractors/dp/B004SFLCLO?crid=370LKMPOM80Z5

This is in regards to my first attempt ever.

I am having trouble with focus. My current set-up goes: Prism Star Diagonal 1.25" -> T-Adapter -> 1.25" 25mm Plossl -> T-Ring -> Canon T3i.

I was wondering what I could do to actually achieve focus, if you look at my comment on my first post I linked to a picture of the moon I took that was way out of focus. I need to fix that. Would this item be of any help? and would I need to use a 2" eyepiece with it?

Also, what about this item and this item? Would those help with my focus and will they need a 2" eyepiece?

Thanks guys! baby steps!