Looking for a lens maker

Ok, before you start telling me I'm in the wrong forum, let me explain There are some glass pushers out there that have made a lot of mirrors but have made lenses also. I'm in need of a custom made barlow for a planetary Newtonian project. The final instrument will be 10" F/15. This is a purely visual lunar/planetary instrument. The primary will be F/6. The barlow will be ahead of the diagonal and the secondary obstruction will be only 18% including the housing for the lens/diagonal combination.

The barlow is a flint forward design. At final focus the 100% illuminated field will be 1/2 degree and the star images will be diffraction limited to a 1/4 degree field of view. The glass components for the barlow are BK7/N-SF5.

Any mirror makers out there that are small lens makers too?

Keith

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What about Mr. Keller ?
http://www.astrooptik.com/sonstiges/Newton3Inch/NewtWynne.htm

Royce advertises "Single and multiple element
refractive systems."
http://www.rfroyce.com/products_com.htm

Woden advertises a refractive corrector lens
of their own design. Maybe they could be talked
into a one-off lens?
http://www.wodenoptics.com/optics.html#

Antares probably has the capability....
http://www.antaresoptics.com/

Edmund certainly does, but I'm sure they will
charge a small fortune....
http://www.edmundindustrialoptics.com/us/Capabilities/

Hi Keith:

I am curious about the diffraction limited region. My math says a 10 inch F/6 mirror is diffraction limited to about 0.14 degrees. (I got this number from Nils Olof Carlin's site...3.7mm)

Jon

Keith,
Will you be willing to share the specs on the lens you design? Thanks Bill

Hi Keith,

You might try Surplus Shed (dot com)

Send an email, and they say they can get a lense made. They quoted me one once, although I eventually got it cheaper through other channels.

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Keith Lawson said:

Ok, before you start telling me I'm in the wrong forum, let me explain There are some glass pushers out there that have made a lot of mirrors but have made lenses also. I'm in need of a custom made barlow for a planetary Newtonian project. The final instrument will be 10" F/15. This is a purely visual lunar/planetary instrument. The primary will be F/6. The barlow will be ahead of the diagonal and the secondary obstruction will be only 18% including the housing for the lens/diagonal combination.

The barlow is a flint forward design. At final focus the 100% illuminated field will be 1/2 degree and the star images will be diffraction limited to a 1/4 degree field of view. The glass components for the barlow are BK7/N-SF5.

Any mirror makers out there that are small lens makers too?

Keith

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Lots of custom shops out there that will do prototype designs like this. Choose one that has the ability to coat optics as well, to help keep costs down. Expect to spend, for something like this, anywhere in the $100 to $1K range, and likely towards the middle-to-higher end and a lead-time from a week to a month. You'll want to look for small to middle-sized shops. Like you said, Edmunds is too big to concern itself with small fish (they've no-bid requests for 2-dozen custom parts before..don't know how they make money that's for sure). Just be sure that you've fully specified your design. That is, fully dimensioned including tolerances, surface finishes, clear apertures, etc. You'll want to see how tolerances affect the design. That is, tweak the radius of curvatures, thickness, etc., to see how it affects performance. If the design is too sensitive or if the tolerances need to be too tight, any shop you choose will either (a) charge you an arm and a leg, or (b) say they can't or won't make the parts. And, if you don't fully spec out the design (a mechanical drawing is preferable), they may not touch it either and/or you may not get what you wanted.

Something to keep in mind. Hope it helps,
Jason