4" Charles Frank Newton 1950s-60s

[ColinBallycastle]

I'm a newbie to the forum so, hello.

I've just come into possession of a 4" Charles Frank Newt with a stonker of the original cast iron stand, having only owned binoculars to date with an interest in their historical development. 

It belonged to my sister-in-law whose science lecturer parents bought it for her second-hand as a starter telescope in the late 60s.

Unfortunately, it's missing the eyepiece which seems to be 1 1/4" diametre, taken from the inside of the threaded focus barrel which is still in place.

Is it possible to find a replacement, or do modern push-to-fit alternatives work satisfactorily? 

Just regarding an item which I found most interesting, is that the finderscope is a Lee Enfield sniper scope with broad arrow marks, probably from WW2 as it is a no. 42 Mk1 rather than a no.32.

I see from the history notes that the company bought and auctioned a lot of army surplus stock, having made items to order for the military. Perhaps the 4" reflector version was made using a combination of army surplus and company parts? 

I would love to hear any thoughts about how to move forward with the project.

[Peter Drew]

The eyepiece fitting is 1.25" RAS (Royal Astronomical Society) thread, 16 threads per inch.  The aperture will probably be just a bit too small to accept standard 1.25" fit eyepieces, a little filing might work.      🙂 

[Cosmic Geoff]

If you want to keep it authentic, brass RAS threaded eyepieces come up from time to time on ebay.   I bought (and re-sold) a couple, and found they would just fit into a modern 1.25" diagonal, which gives one an idea of the overall diameter.

[ColinBallycastle]

Thanks for your replies and I really appreciate the knowledgeable insights - I did wonder what the 'RAS' descriptor implied!  I have ordered a basic modern  1.25" from ebay as a starting point and will proceed from there.

For context,  I have a static van in a small, coastal site outside Ballycastle on the north Antrim coast beside Fairhead (prominent basalt cliffs) opposite Rathlin Island, and close to Carrick-a-Rede which is an official Dark Sky Discovery Site, known for views of the Milky Way and the Aurora Borealis.

I'm hoping that I can return the Frank to working order to enjoy those night skies!