x0.8 減焦平場鏡 7A (P-Flat7A)

Finally got my flat frames looking perfectly even across the whole field with this reducer, and the back focus adjustment was surprisingly straightforward. The build quality feels solid, too.

My stars went from slightly elongated at the corners to round across the whole frame after adding this 0.8x reducer. Backfocus spacing was picky and took me an evening to dial in, but once I got it right the field flattened out nicely.

Threaded this onto my 61mm refractor and the corner stars finally look round instead of streaked. The x0.8 reduction is exactly what I needed to fit the whole nebula in frame. Backspacing was dead on at 55mm, no shims required.