OWL Astronomy

OWL Astronomy Products
Eyepieces, Telescopes, Binoculars, Microscopes
Knight OWL Diagonals

Knight OWL Diagonals

View objects at high elevations without breaking your back or your budget.

Knight OWL 2" Diagonals

Excellent Quality Dielectric Diagonal
Mirror Star Diagonal - 99+% Reflectivity!

If you paid for high performance coatings for your telescope,
why lose 8% of your light using a standard diagonal?

Knight OWL Eyepieces

Provides a Comfortable 90 Degree View from your Refractor

Fits Standard 2" (50.8 mm) Diameter Focus Tubes
Use Both 2" (50.8 mm) and 1.25" (31.75 mm) Eyepieces

High Quality 2 inch Dielectric Diagonal
High Quality Dielectric Diagonal with Attention to Detail
High Quality 2 inch Dielectric Diagonal
Detail of Eyepiece End (Shows Compression Ring in both 2 inch and 1.25 inch adapter)
These high quality 2 inch dielectric diagonals come to us from the same company that makes our great Knight OWL Ultra-wide angle eyepieces. The mirror has a 1/10th wave flat optical glass surface. The housing is machined from solid aluminum. The barrel is threaded to accept standard 2" filters. The 2" eyepiece holder uses a non-marring brass compression ring to secure your valuable eyepieces. The 1.25" adapter also has a non-marring brass compression ring. Both sizes of eyepieces may be used and are protected from dings and scratches that would result from a standard set-screw.

This 2" diagonal works with any Refractor that accepts a 2" star diagonals. It can also be used with Schmidt-Cassegrain or Maksutov-Cassegrain with an optional 2 inch visual back (See below). We have these available for SCTs. If you paid for expensive high performance coatings on your SCT or Refractor, a dielectric diagonal is especially important. A standard aluminized diagonal has about 92% reflectance. And this decreases with time as the aluminum mirror surface ages. We list our dielectric coated diagonals at 99+% reflectance, but this does not tell the complete story. While the reflectance is at a little more than 99% for the deep violet and reds, the reflectance for a the rest of the spectrum is essentially 100%. For the vast majority of the visible spectrum, the reflectance does not vary more than about 0.1% below 100%. And the dielectric surface does not age like aluminum. This combination leads to the equivalent of a little more light grasp compared to standard diagonals - even very expensive ones. That is like having a slightly larger telescope!

2" Dielectric Diagonal - 99+% Reflectivity (with high quality 1.25" adapter)
Threaded for 2" filters and for our Knight OWL 2" ED Barlow
Intro Price Only: $95.95.

High Quality 2" Visual Back - SCT Adapter

Now you can use 2" eyepieces, diagonals, and other
accessories an any Schmidt-Cassegrain Telescope!

One of our newest products

Knight OWL Eyepieces

This adapter is sturdy, all metal construction.

Detail of Visual Back - SCT Adapter
This SCT adapter has a brass retaining ring
to protect your eyepieces

Detail of Bottom of the Visual Back
Screws onto the back of your SCT to allow use of 2"
eyepieces and accessories.

This is a sturdy adapter to allow the use of your 2" eyepieces, diagonals, and other accessories on your SCT. The use of 2 inch eyepieces gives you a greater field of view on your telescope. This is very sturdy visual back and of all metal construction.

One fine point should be mentioned. When you tighten down the set screw on an eyepiece with most such adapters you have a chance of marring the finish of the eyepiece barrel. As shown in the photo, there is an brass retaining ring on our adapter that is tightened by the set screw. Instead of your eyepiece being held by one set screw causing nicks, it is held around a large portion of its diameter by the softer brass ring. Don't destroy the appearance of your high end Tele VueŽ and MeadeŽ eyepieces. There were no compromises and a lot of thought going into the design of this adapter.
2" Visual Back (separate purchase)
Price: $19.95.
2" Visual Back (with 2" diagonal or
2" eyepiece purchase only)
Sale Price: $9.95.

Last Updated November 23, 2010