Objective Lens 55-60.5 Diam, 700-750mm Focal Length

[robgjames]

I'm restoring a very old (circa 1800) Blunt library telescope of nominal 2" size and am having trouble finding a physically compatible objective lens (the original broken and long gone). It should ideally be an achromatic doublet with key parameters 55-60.5mm actual Diam so as to fit the mounting, and 700-750mm Focal Length to achieve focus.

Please let me know if you can supply anything suitable. The objective is the most important part, and I would love to find something of the era, but I'm resigned to most likely having to use a modern lens, quite possibly from a low cost telescope as there were a few around these specs - they just havent been turning up lately.

I'm also on the lookout for any old brass eyepieces - particularly pre 1900 if by chance you have any to sell.

Regards Rob

[N1]

Robert, have a look on here. (https://www.aliexpress.com/item/4000344345392.html?spm=a2g0o.produc tlist.0.0.7fb5424e3Uxblb&algo_pvid=87877aec-810f-4c9d-9786-dab3b8fe4ba2&algo_expid=87877aec-810f-4c9d-9786-dab3b8fe4ba2-16&btsid=7a98ece7-6dec-4340-898b-9f9167c6cbbe&ws_ab_test=searchweb0_0,searchweb20 1602_2,searchweb201603_52)
Might as well use new glass. There's a 60/700 in there, among others.
A search for "achromat objective" will give more results.
Shipping is reasonably prompt and has been hassle free for me so far. Just received some nice optical glass spheres from a seller there.

[fsphotography]

There is a 60x700mm lens on Cloudy nights for $13 us. Add no. 191085.
Good honest seller.

Frank.