I have an FS-78 I use for visual and video astronomy. I have adapted it to use the Meade .63 SCT focal reducer/field flattener I already have. I notice the quality refractor manufactures each have a .8 focal reducer/corrector.
On video (with a 1/3" chip @ 640 x 480 resolution) I do not notice a problem. But I have not done a close enough comparison of the view to tell if distortion is being added.
My questions:
Is there a major difference in the design of these reducers. Will a .63 focal reducer/flattener designed for an SCT introduce a significant distortion of the field when used with a refractor (such as the FS-78)?
Also: is there a reason optically why a reduction of only .8 seems to be prevelent for refractors? Are these propriatory to each manufaturer's models?
This is a repeat of a post I put on the Takahashi site.
Any input is appreciated.
Thanks
Steven Jindra
On video (with a 1/3" chip @ 640 x 480 resolution) I do not notice a problem. But I have not done a close enough comparison of the view to tell if distortion is being added.
My questions:
Is there a major difference in the design of these reducers. Will a .63 focal reducer/flattener designed for an SCT introduce a significant distortion of the field when used with a refractor (such as the FS-78)?
Also: is there a reason optically why a reduction of only .8 seems to be prevelent for refractors? Are these propriatory to each manufaturer's models?
This is a repeat of a post I put on the Takahashi site.
Any input is appreciated.
Thanks
Steven Jindra
