Red Dot Apo Artar, 24 inch

Does anyone know the filter size for the Red Dot Artar 600mm lens ( 24 inch )? If so, I would appreciate having the information.

There are different sizes involved. I've seen aluminium barrels & brass barrels each with different threads. I don't have a 24 incher anymore but on my 19 incher I used Lee 4x4s in Calumet cardboard frames and a Lee gel-snap filter holder,

I just remembered my old 24 incher had a slot in the barrel for filters or whatever, so theoretically you don't need threaded filters.

The Lee gel-snap is great solution. If you want to use threaded filters you need to have an adapter made. I don't know when yours was made but the later ones from the fifties to seventies, say, used series filters (series six, series seven, series eight). Those aren't compatible with modern filter sizes. If you find an old series filter holder and filters to fit you've got it made but that seems quite difficult. SK Grimes makes adapters for series to modern threaded filters. They can do it without the lens but they prefer that you ship the lens to them so the adapter can be confirmed as correct. I think the adapter for my 19" Red Dot Artar cost $80.00 and took six to eight weeks (I might have taken an extra long time because I had other work done also. Here is the link to SK Grimes, you can e-mail them for information.

http://www.skgrimes.com/

They use push-on series filters, not screw-in filters which were popularized by Japanese 35mm cameras about half a century after the Artar was designed.

Cheers, Steve