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Tele Vue DeLite 4mm 62° Eyepiece - 1.25"
The Tele Vue DeLite 4mm 62° Eyepiece is a high-magnification optic designed to deliver the high-contrast performance of the Delos series in a more compact, lightweight 1.25-inch format. It is engineered to provide a 20mm eye relief while maintaining an extremely high degree of correction for lateral color and scatter. This 4mm focal length is primarily intended for critical lunar, planetary, and double-star observation in systems where high power is required without sacrificing viewing comfort.
20mm Eye Relief and Mechanical Versatility
The consistent 20mm eye relief and sliding, locking eyeguard assembly allow observers to precisely match the exit pupil position to their eye, which is essential for avoiding blackouts at such short focal lengths. This mechanical design prevents the "finicky" eye placement often associated with ultra-short focal length wide-angle eyepieces.
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Dioptrx Compatibility: The 1.25-inch housing is fully compatible with the Tele Vue Dioptrx corrector, enabling users to correct for eyesight astigmatism without wearing spectacles.
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Locking Eyeguard: The adjustable housing can be set and locked at a specific height, ensuring repeatable eye placement for extended sessions on objects like Mars or Jupiter.
High-Magnification Utility in f/ratio Systems
In an f/7 refractor, the Tele Vue DeLite 4mm produces a 0.57mm exit pupil and high magnification, suitable for resolving the Rima Hadley on the Moon or the GRS on Jupiter. In an f/10 Schmidt-Cassegrain (SCT), it yields a 0.4mm exit pupil, reaching the upper limits of useful magnification for splitting tight double stars like Beta Cygni (Albireo) under excellent atmospheric conditions.
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Small Exit Pupil Geometry: The 4mm focal length maintains a 0.8mm exit pupil in f/5 Newtonians, providing sufficient image brightness for high-power views of the Hercules Cluster (M13).
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Group B Parfocality: This eyepiece is parfocal with Tele Vue's 1.25-inch Plössl, Panoptic, and Nagler designs, minimizing focus travel when changing magnifications.
Operational Comparison
The Tele Vue DeLite 4mm offers a specific balance of mass, eye relief, and field size compared to other short focal length Tele Vue designs.
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vs. Tele Vue 4.5mm Delos: The DeLite 4mm is roughly 30% lighter and smaller, making it easier to balance on lightweight mounts, though it provides 10° less apparent field.
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vs. Tele Vue 3-6mm Nagler Zoom: The DeLite 4mm provides a wider 62° field (vs 50°) and significantly longer eye relief (20mm vs 10mm), allowing for more comfortable long-duration viewing.
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Is the Tele Vue DeLite 4mm compatible with Dioptrx?
Yes, the Tele Vue DeLite 4mm features a removable eyeguard that permits the installation of a Dioptrx corrector, allowing observers with astigmatism to see sharp detail without wearing glasses.
How does the Tele Vue DeLite 4mm compare to the 4.5mm Delos?
The Tele Vue DeLite 4mm is more compact and weighs significantly less than the 4.5mm Delos, which is beneficial for binoviewer use. While the Delos has a 72° field, both share the same 20mm eye relief and high-contrast optical coatings.
Will the Tele Vue DeLite 4mm work in an f/10 SCT?
In an f/10 system, the Tele Vue DeLite 4mm produces very high magnification (500x in a 2000mm FL scope) and a 0.4mm exit pupil. This is typically only useful during nights of exceptional atmospheric stability for lunar and double star work.
What is the field stop diameter of the Tele Vue DeLite 4mm?
The Tele Vue DeLite 4mm has a 4.3mm field stop. This determines the true field of view, which can be calculated by dividing the field stop by the telescope's focal length and multiplying by 57.3.
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| Focal Length |
4 mm |
| Apparent Field of View |
62° |
| Eye Relief |
20 mm |
| Field Stop Diameter |
4.3 mm |
| Barrel Size |
1.25" |
| Weight |
7.6 oz (215 g) |
| Parfocal |
Group B |
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TeleVue 5-Year Limited Warranty for Telescopes and Accessories
