Salva

Flattener cost £179 ... is it really necessary? Supposing I have only a 63mm on the lens and 48mm on the T-ring, how am I suppose to insert a 1.25" narrowband filter? Thanks in advance

Many thanks

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

https://www.nightblight.cpre.org.uk/maps/ Try this