Regular achromat scopes are actually expensive!

[Ags]

21 hours ago, Ags said:

Forget upgrading cheap achros with better focusers etc... i would be happy with ED glass in a cheap ST80 OTA!

Actually, if i could find a cheap 400-420 mm focal length ED lens group I could convert my ST80 to an STED80! I quite like the ST80 focuser. An interior decorator would call it "honest".

[vlaiv]

22 minutes ago, Ags said:

Actually, if i could find a cheap 400-420 mm focal length ED lens group I could convert my ST80 to an STED80! I quite like the ST80 focuser. An interior decorator would call it "honest".

Maybe this would fit the bill?

https://www.teleskop-express.de/shop/product_info.php/info/p4711_TS-Optics-ED-refractor-lens-70-420-mm--w--adjustable-mount.html

It is a smaller aperture but focal length is almost exact - not fiddling with tube length change will be required. I think that it is easier to fit smaller lens cell in bigger tube then other way around.

[F15Rules]

15 hours ago, John said:

I don't think I've ever bought a new achromat other than the TAL100R back in 1999 which at £250 with a mount and good eyepieces, delivered from Siberia was quite a bargain I think.

 

That's interesting John, I too bought my first, also a 100R, in 2000. I remember I bought it from Warehouse Express and paid £249.95 for it including shipping..

It was delivered to my works office, and arrived in a huge Siberian Birch and Ply "coffin" wooden crate and my colleague who took delivery didn't know what to make of it! 

It (the coffin) was covered in scratches and several deep gouges, not pretty, but then it had travelled overland from Siberia by truck apparently, and it certainly did its' job: the scope, mount and tripod were immaculate. The 100R had the most beautiful purple coatings, very reminiscent of Lomo and Lzos objectives.

I owned several of the later 100RS versions, but I always felt the original purple lens versions were the best..so sharp and with great contrast and slightly less CA, I felt.

However, the RS had a much better focuser, initially a 2" Rack and Pinion and later a very smooth, rotating 2" Crayford focuser - I bought one of the first versions with the Crayford, I think around 2010 or 2011.

Both great achromats, sharp, lightweight and easy to use.

I've actually got a mint 100RS OTA at the moment, dating from 2011.. I thought my son in law would want it it, to replace his rather bulkier Evostar 120mm F8, but although he has a PHD in Astrophysics he seems disinclined to actually get out under the stars for real! 🤔🙄..

So, I'll probably let it go in the new year as I'm trying to stick to just two scopes and with one of them being the FS128, I can't really justify keeping the Tal long term.

Dave

Edited December 12, 2020 by F15Rules