You think Apo Scopes are Expensive?

[Stub Mandrel]

I bought a coated 60mm achro doublet from Astromedia and made a fine guidescope with it, it cost under a tenner. Sadly they are sold out.

I've been looking for something similar and found this, which I'm not entirely convinced is much better and doesn't even appear to be coated:

https://www.laser2000.co.uk/product/dlb-60-250pm/achromatic-doublet-60mm-diameter-250mm-focal-length

And you think apo scopes are expensive?

[Craney]

Focal length quoted to a 1/10th of a mm .......... phoar!!  that must count for something....

[Alien 13]

Looks like a bargain to me, have bought lenses in the past and they are not cheap..

Alan

[Astrobits]

Individual lenses made by these top end companies always have a ridiculous price tag. If your requirements are very specific then there is nowhere else to go. At the cheaper end is Edmond Optics which will sell you a 50mm achromat for £120 +vat

However if your requirements can fit around particular specifications then you can get achromatic lenses 50mm or larger for much less. A pair of 50mm achromats with about 250mm focal length can be had for way less than £100. You will get two eyepieces thrown in for free. They are called binoculars.

Nigel

 

[Stub Mandrel]

If I settle for an alleged 1/4 way accuracy I could by 20 from China for a few tens of dollars, coating extra!

At that price I could buy a batch and chuck any rejects. For making guidescopes it's literally cheaper than buying 'toy' scopes and throwing away everything but the lens.

Grinding custom lenses isn't expensive these days with CNC machines.

I would believe a couple of hundred pounds for a UK ground custom lens, but over two grand for a standard item?