Hi all,
atm I have a Canon Eos 500D with a EF300mm mounted on a Star Adventure Pro.
I'm going to upgrade my equipment and buy:
- William Optics Zenithstar 81 f/6.9 Doublet APO Refractor
- William Optics P-FLAT6AIII Adjustable Field Flattener ... (M48 outside for the T-ring)
- William Optics Copper M48 T Mount
No guiding scope for the moment.
I need a couple of narrow band filters, the flattener mentioned above accept 2" for filter inside. The cost of a narrow band 2" filter is £260 !! ...with this configuration, is it possible to use a 1.25" filter instead of a 2", without losing sharpness etc? How?
Thanks