Objective lenses for refractors

[bojan]

I am not sure how good those are... but it may be interesting for some of us :P

http://stores.ebay.com/Telescope-Diy__W0QQ_sidZ117144278QQ_trksidZp4 634Q2ec0Q2em14?_pgn=1

[DavidU]

They seem to test quite well. I had considered the 152 x 1200 FH.
http://translate.google.com/translate?js=y&prev=_t&hl=en&ie=UTF-8&u=http%3A%2F%2Fwww.astro-foren.de%2Fshowthread.php%3Fp%3D417 13%23post41713&sl=de&tl=en&history_state0=

[lacad01]

Interesting. I've been contemplating getting something similar from Surplus Shed and putting together a tube out of carbon fibre. Been reading a lot up from the Cloudy Nights ATM forums.
127mm 1200 (http://www.surplusshed.com/pages/item/l3967.html)

[pmrid]

Good grief! A 10 inch ir-spaced achro F6.25; or even a 12" F10; starts the old DIY heart beating a little faster doesn't it?
Peter

[bojan]

O yeah :D

[lacad01]

Stumbled upon this yahoo group which would be an interesting resource for refractor ATM...
http://tech.groups.yahoo.com/group/HomemadeRefractorTelescopes/

[el_draco]

Sweet Mary mother of Hughy.... Phew. Imagine trying to keep it steady in a breeze.... :eyepop:

[Saturnine]

Hi All

I came across this new Chinese supplier a few months ago on Ebay and the range and prices got my attention as I was in need of a new project , to go with the 4 or 5 that I've already half finished, so I bought the 131 X 1000 to try out. Got it to my door for a little over $150 AUD and when I do finish the scope I will pass on my thoughts as to the quality of the lens, I'm no expert optically but can compare it to my 4" f/9 Jaegers and 6" f/6.5 Antares as it will sit nicely between them at 5" f/8 .
The Surplus Shed 5" lens are too hard to get, they sell to the locals as fast as they arrive at S.S. we don't get much of a look in unless your very persistent or lucky.

Jeff

[kinetic]

Bill (Glenhuon ) would be the bloke with some tips on these.
I believe Bill has dabbled with some Surplus Shed type objectives
and polypipe etc and made a scope or two...

Steve

[bojan]

Someone send me this link:
http://www.astro-foren.de/showthread.php?p=43090#post43090
Not too good, it seems.. but reasonable price/performance ratio, especially for lower powers.

[Saturnine]

Hello Again
Hope it's not to late to resurrect this thread. been doing too much reading and not enough replying, thanks for the link to Rohrs' site Bojan, I'd not thought that he would have tested one of these Diy 131mm x 1000mm lens but it seems that he has and the results are not as good as I wanted them to be but acceptable for the money.
The Strehl figure is the weak link because of astigmatism which may be caused by some misalighnment of the crown & flint or the objective being pinched by an overtight retaining ring,so a bit of tinkering may alleviate some of the "problems". At any rate the lens should work at low to medium powers.
This will be my 6th or 7th home made refractor using new or second hand optics and mostly aluminium tube though 2 have used poly tube and they have worked fine, this one, the 5" f8 will be poly as well.
Also thanks Adam, for the link to the Yahoo Refractor Group, should be lots of info on there to digest.

Kind Regards
Jeff