Where do i get lens's????

[Insane Climber (Jason)]

Can anyone in aus please point me in the right direction to buy an objective lens for refractor. I need something of low quality around 80mm f4.

Thanks in advance

Jas

[Wavytone]

I'll suggest try ringing Bintel, they should know.

Also try the catalog at A.E. Jaegers http://www.ajaegers.com/ however the postage will probably be 3X what the lens is worth.

[jjjnettie (Jeanette)]

Try here
www.surplushed.com

[MrB (Simon)]

edit: Ignore me, jjj beat me to it.

[jjjnettie (Jeanette)]

beat ya

[Insane Climber (Jason)]

Thank you, I didn't really want to buy from overseas. But Surplus shed has paypal which is easy. I just purchased a 60mm F2.5 for $5us plus postage. Wow thats cheap.

Thanks again jjj
Jas

[jjjnettie (Jeanette)]

Glad to be of service Jas

[MrB (Simon)]

Hehe, good stuff eh?
They sure have become pretty common knowledge these days, but their prices stay very low. Good on em!

Will be buying a few Acro-objectives myself soon for a finder, a guide scope etc.

[Insane Climber (Jason)]

That sounds like a good idea MrB, im gettin this one for a finder, but after looking through the list it looks like a long focal length guide scope can be done very cheap.

[Wavytone]

I suspect you're going to be disappointed by the lenses from SurplusShed, f/2.8 is way too fast for a doublet to be any good visually. OK as a condenser - which is what such lenses were made for - but not as a small telescope (ie. a finder). What you should be looking for is a doublet around 60mm aperture at f/5 (300mm focal length).

I've looked at their site before and yes the stuff is cheap... but not much practical use, which is why I refrained from suggesting it.

There is another alternative - old camera lenses - I have two from my ancient SLR which i use as finders. Both are OK at low power with an old 20mm Erfle eyepiece, but they aren't diffraction limited (not even close off-axis) so useless for higher power:

- a 135mm focal length f/2.8 telephoto, it gives about 7X and a very bright field of view, excellent as a finder.

- a 500mm f/8 mirror lens, which gives 25X with the same eyepiece. It's useful for projecting the sun, the resolution is good enough for that. Aperture about 60mm and overall length about 100mm, so it's very compact.

You can find similar lenses for next to nothing in auctions.

Sigma made a 600mm f/8 mirror lens which as I recall gave fairly good image quality as a telescope; if you find one it would probably serve well as a guidescope.

[Glenhuon (Bill)]

I've made a couple of SS scopes. The 80mm F5 is used as a guide scope, performs very well and was reasonably cheap to build.
I've a 70mm f6 thats not completed, still looking for a decent focuser, the plastic SS ones are pretty rough but enough to try it out.
I doubt that I'll use the 70mm, drop me a PM and we can come to some arrangement if your interested.

Bill

[bojan]

Old russian lenses (for Zenit cameras, ebay) are pretty good and cheap.. even new ones, have a look at rugift.com.

[anj026]

I know you mentioned not wanting to buy from overseas however I can recomend Hands on Optics in the US. They sell Antares lenses. They have cemented binocular lenses 80mm focal length 340mm for $35 US and longer focal length ones (480, 560 and 700mm) for $61 US. I purchased a 90mm lens from them online and had good service.

[Insane Climber (Jason)]

Hello

Thanks for all the advice there. For the moment i have never made a scope befor, and just wanna try mounting a focal reducer and web cam ccd to the back of something cheap. Once i have that done i will get a better len's and try something better. Thanks for the offer Bill, will get back to you once i have done a bit of experimenting.

Jas