Tele Vue DeLite 7mm 62° Eyepiece - 1.25"

The DeLite Line

Each DeLite has 20mm of eye relief and a 62° apparent field. Based on Tele Vue's Delos design experience, it keeps the size and weight down while achieving the best sharpness, linearity (freedom from pincushion distortion) and ghost suppression over the entire field for any speed (f/#) telescope.

62° Apparent Field and 7.5mm Field Stop

The true field depends on the field stop diameter and the telescope's focal length. The DeLite manual lists 7.5mm for the 7mm.

You can calculate the true field of view (TFoV) in your specific telescope using Tele Vue's formula: TFoV = (Eyepiece Field Stop ÷ Telescope Focal Length) × 57.3. For example, in a telescope with a 1000mm focal length, the DeLite 7mm gives 143x and a 0.43° true field, room for the Trapezium in the core of the Orion Nebula (M42) or the Ring Nebula (M57).

Magnification and Exit Pupils from 0.5mm to 1.6mm

In an 8" f/10 Schmidt-Cassegrain (2032mm) it gives 290x. The atmosphere usually limits planetary observing to about 300x, whatever the aperture.

Tele Vue's chart gives:

• At f/4.5: 1.6mm exit pupil
• At f/5.2: 1.3mm exit pupil
• At f/7 (Apochromatic Refractor): 1.0mm exit pupil
• At f/10 (SCT/MCT): 0.7mm exit pupil
• At f/14 (Long Refractor/MCT): 0.5mm exit pupil

20mm Eye Relief for Eyeglass and Dioptrx Users

Every DeLite has 20mm of eye relief, at the top of the 15mm to 20mm recommended for observers who wear glasses to correct astigmatism. It also minimizes eye lens fogging in cold weather. At exit pupils of 1mm or less you probably will not need glasses, which covers this eyepiece in most telescopes.

The DeLite is ideal for DIOPTRX (Y in the chart), which attaches and locks onto the top and rotates to match your astigmatic axis.

The Adjustable, Locking Eyeguard Housing

The adjustable, locking eyeguard housing is in two pieces. In the down position it gives eyeglass wearers full eye relief; an eye too far in or out causes edge darkening and field loss.

Without glasses, grasp a grip ring in each hand and twist the lower one to the left to loosen it, pull the eyeguard fully out, then slide it down while looking through the eyepiece until you just see the full field with your peripheral vision. Note the height with the green indicator lines and lock it by twisting the lower ring to the right. Be careful not to unscrew the lower barrel section when rotating the housing.

Sharpness and Linearity Across the 62° Field

It delivers sharpness, linearity and ghost suppression over the entire field for any speed (f/#) telescope.

Linearity is freedom from pincushion distortion, which makes magnification grow toward the field edge so straight lines away from the center look curved.

Paracorr Type-2 for f/5 and Faster Newtonians

Newtonian and Dobsonian telescopes show coma, which makes off-center stars look like little comets; no eyepiece removes it. Tele Vue's Paracorr Type-2 eliminates it, and scopes faster than f/5.0 see the greatest results.

It goes in a 2" focuser like a 2" Barlow and has a 1.15x magnification factor, so the 7mm acts like a 6.1mm.

Achieving Higher Powers with 2x-5x Barlows and Powermates

Tele Vue makes Barlows and Powermates in 2x, 2.5x, 3x, 4x and 5x.

A 2x makes the 7mm act like a 3.5mm. In short focal length telescopes that helps: in a TV-76 (480mm) it takes 69x to 137x. In an 8" SCT the 7mm alone is already near 300x, the usual atmospheric limit.

DeLite 7mm vs. Nagler 7mm and Delos 8mm

Comparisons from Tele Vue's chart:

• vs. Nagler Type 6 7mm: 82° apparent field and a 9.7mm field stop, so more sky at the same power, with 12mm of eye relief and Dioptrx with an adapter (Y*).
• vs. Delos 8mm: The 8mm Delos provides a wider 72° field and the same comfortable 20mm of eye relief as the DeLite. It has a 9.9mm field stop and weighs 16 oz against the DeLite's 7.3 oz.

Dioptrx, FoneMate, and BandMate Filter Integration

Besides Dioptrx, Tele Vue's DeLite manual lists:

• FoneMate: The smartphone adapter (SFA-0001) clamps to the eyepiece for still, video or timelapse images.
• BandMate Filters: The barrel takes M28.5x0.6 filters. BandMate Nebustar, O-III and H-Beta pass select wavelengths and darken the sky so nebulae "pop out".

A 1.25" Build with a Lifetime Limited Warranty

The DeLite 7mm has a 1¼" barrel and weighs 7.3 oz (207 g). The manual warns: "To avoid getting dust and dirt into the eyepiece Do not unscrew the chrome barrel!"

Tele Vue eyepieces carry a Lifetime Limited warranty against defects in material or workmanship.