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Thalestris24

Small lens suppliers?

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I'm searching around for a supplier for some small achromatic doublets for the spectrometer I'm building. I have Thorlabs part numbers but they seem rather expensive for just some small lenses - 

a 0.5" (12.7mm) dia, fl = 30mm, and a 30mm dia, fl = 100mm both AR coated. I can't find anything on Ebay or even Google though I'm sure there must be someone, somewhere in the world?

Thanks for any help/suggestions :)

Louise

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8 minutes ago, johninderby said:

Take a look at this place. They carry a lot of different types so you might be able to make up something suitable.

https://www.brecklandscientific.co.uk/Biconvex-Small-Lenses-s/9276.htm

Thanks for the suggestion but they are only cheap biconvex lenses. Ideally I need coated achromatic doublets and I expect to pay double figures for them - but Thorlabs are pricey:

Autoguider Lens
Collimator Lens

Cheers

Louise

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5 minutes ago, johninderby said:

How about objectives from small binoculars?

https://www.astroboot.co.uk/search.php?needle=Binocular

They probably would be ok but need to be specific diameters and focal lengths - as per the Thorlabs link. I suppose I'll have to pay their prices if I can't find an alternative source :( AliExpress might be a possible.

Cheers

Louise

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49 minutes ago, Kev M said:

Would an  eyepiece not do for the 30mm ?

 

Failing that.... https://www.surplusshed.com/

 

 

 

 

x2 for surplus shed. I use them fairly regularly, very reliable, they may have what you want and if not ask and they may be able to find it. Standard USA postal service but not too long a wait.   They had some cracking 5 inch objective lenses a wee while back , would make a nice project. :) 

Jim 

Edited by saac

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46 minutes ago, Kev M said:

Would an  eyepiece not do for the 30mm ?

Failing that.... https://www.surplusshed.com/

No eyepiece wouldn't do, I don't think. The design essentially calls for single, unmounted doublets that can be fixed to lens holders:

OpticalComponents.PNG.fce24fb2bd8612c384d6781e1263ba8b.PNG

Surplushed a possible - similar to AliExpress

Thanks

Louise

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1 minute ago, saac said:

x2 for surplus shed. I use them fairly regularly, very reliable, they may have what you want and if not ask and they may be able to find it. Standard USA postal service but not too long a wait. 

Jim 

How much do they charge for postage? Did you have to pay import duty/vat? I think the cost of a few lenses should be below import duty charges - hopefully!

Louise

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I can't remember exactly Lousie just that it was all very reasonable. I've bought lenses and a beam splitter for an interferometer project and also a set of lenses to build a Rochester cloaking optical train.  From what I recall there was no import duty as such or if there was it was pretty insignificant.  The benefit of course is compared to the likes of Edmund Optics and similar Surplus Shed prices are way cheaper. It's just a matter of them having what you need.  I'd highly recommend them though.

 

Jim 

Edited by saac

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9 minutes ago, saac said:

I can't remember exactly Lousie just that it was all very reasonable. I've bought lenses and a beam splitter for an interferometer project and also a set of lenses to build a Rochester cloaking optical train.  From what I recall there was no import duty as such or if there was it was pretty insignificant.  The benefit of course is compared to the likes of Edmund Optics and similar Surplus Shed prices are way cheaper. It's just a matter of them having what you need.  I'd highly recommend them though.

 

Jim 

Ok, cheers. They sound similar to AliExpress.

Louise

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Gosh, that looks complicated!

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4 minutes ago, Gina said:

Gosh, that looks complicated!

Nah, just a couple of mirrors, a couple of lenses - and a slit :) One lens is for the autoguider, one to collimate, and another for the camera. Simples.

Louise

Plus a diffraction grating, of course :) 

Edited by Thalestris24
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SurplusShed is my first try when I need lenses etc. but when I needed the lenses as specified for Lowspec they didn't have any.

Eric.

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Just now, ejp1684 said:

SurplusShed is my first try when I need lenses etc. but when I needed the lenses as specified for Lowspec they didn't have any.

Eric.

I think optically there is some leaway for the lens' focal length and diameters. Might have to print some different sized holders. If I can get them cheap, I'll try some that are close to the design values. If the worst comes to the worst, can get the expensive ones from Thorlabs. The total cost will still be a lot cheaper than a purchased spectroscope.

Louise 

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Whilst I have never bought anything from them, I too would give surplusshed a go.  They have been around for a long time, so must be doing something right.  They will tell what the postage is, but import duty and other charges seem to be a bit random. 

It's worth getting on their mailing list just to see some bargains.

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13 minutes ago, Oldfort said:

Whilst I have never bought anything from them, I too would give surplusshed a go.  They have been around for a long time, so must be doing something right.  They will tell what the postage is, but import duty and other charges seem to be a bit random. 

It's worth getting on their mailing list just to see some bargains.

Yeah, I'll drop them a line tomorrow and see if they can supply any of the lenses (or ones that are close to the spec) on my parts list. If the postage is reasonable that would be good :) I'll ask about diffraction gratings as well.

Louise

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59 minutes ago, Thalestris24 said:

Yeah, I'll drop them a line tomorrow and see if they can supply any of the lenses (or ones that are close to the spec) on my parts list. If the postage is reasonable that would be good :) I'll ask about diffraction gratings as well.

 

Good gratings are quite pricey, so buying within the EU (for the time being) could save some aggravation.  Depends on what you are looking for.

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6 minutes ago, Oldfort said:

Good gratings are quite pricey, so buying within the EU (for the time being) could save some aggravation.  Depends on what you are looking for.

Yeah, the 1800 line reflection grating is ~£120 with vat, from Thorlabs. I'm not likely to find one at SurplusShed but there's no harm in asking!

Louise

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Louise,

Surplus Shed don't supply gratings...

I thought Paul's LowSpec required a 600 l/mm grating?

I buy all my gratings from Optometrics (now Dynasil) - highly recommended.

Ken

 

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5 minutes ago, Merlin66 said:

Louise,

Surplus Shed don't supply gratings...

I thought Paul's LowSpec required a 600 l/mm grating?

I buy all my gratings from Optometrics (now Dynasil) - highly recommended.

Ken

 

I believe Paul upgraded it to 1800 line/mm - this one . I probably won't get it cheaper than that Thorlabs one. I couldn't see an equivalent on Optometrics/Dynasil? I'm not sure that I'll achieve the high resolution but I'm aiming high! :) The Lowspec can alternatively use a lower resolution grating and I think you can just lift one out and put another (600line/mm) one in.

Louise

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Louise,

Ah, I see you're calling up a 6mm thick grating....I always used the 9.5mm....

Ken

 

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