DIY Ultra Wide Binoculars

Astronomy magazine recently had an ad for a pair of ultra wide field binoculars from Kasai Trading.  These quirky binoculars have a magnification of just 2.3X with 42mm objectives but give a whopping 28º field of view, about four times larger than that of standard binoculars. The Vixen 2.1×42 constellation binoculars are similar and a review and comparison of these models is available.

Image of home build Ultra-Weide Nikon 2x54 binoculars
Home-Built Ultra-Wide Nikon 2×54 binoculars

I found these appealing because the ultra-wide field provides views more like the naked eye while boosting the brightness to compensate for light pollution and aging eyes -only the cost was somewhat prohibitive.

Image Nikon TC-E2 teleconverter
Nikon TC-E2 Teleconverter lens now available as surplus.

Some research revealed a simple do-it-yourself alternative: Nikon 2×54 binos built as described in several posts on The key components are a pair of old Nikon TC-E2 teleconverters. These are high-quality lens, originally selling for over $150, now available as surplus on eBay for as low as $30. All that is really needed, in addition to the lens, is a holder to keep the lens together. Fortunately plans for such a holder suitable for 3D printing have graciously been made available online.

image of a Holder a Nikon Teleconverter suitable for 3D printing.
Holder for a Nikon Teleconverter suitable for 3D printing.

I had a set printed locally at Discount Printing in Burnaby through the 3D Hubs website – uploaded the plans, arranged payment, and the holders arrived via Canada Post a few days later. It was then a simple matter to connect the holders using a M5 bolt and nut from Rona, secure the lens into the holders with some double-sided tape, and attach an old name-tag lanyard as a strap.

I am quite pleased with the results and views provided by these binoculars – from my light polluted Coquitlam yard, I can

  • resolve individual stars in the Pleiades star cluster instead of of seeing just a faint hazy patch
  • see all the stars in the little dipper rather than just Polaris, and
  • find bright stars much earlier in the evening twilight.

Rather that replacing  standard binoculars or a telescope, I think of these binoculars as more like glasses that augment naked eye observing.