{"id":107317,"date":"2026-04-21T12:01:12","date_gmt":"2026-04-21T10:01:12","guid":{"rendered":"https:\/\/www.telescoop.nl\/?post_type=product&p=107317"},"modified":"2026-08-23T15:07:38","modified_gmt":"2026-08-23T13:07:38","slug":"televue-delos-17-3mm-72-degree-wide-angle-eyepiece","status":"publish","type":"product","link":"https:\/\/www.telescoop.nl\/en\/televue-delos-173mm-72-groothoek-oculair\/","title":{"rendered":"TeleVue Delos 17.3mm - 72\u00b0 Wide-Angle Eyepiece"},"content":{"rendered":"

TeleVue Delos 17.3mm: 72\u00b0 Wide-Angle Eyepiece: Delos eyepiece with 72-degree field of view<\/strong><\/h2>\n\n\n\n

The Delos 17.3mm was the longest focal length in the series until the arrival of the 24mm. With a 21.7mm field stop, it is close to the mechanical limit of a 1.25 inch eyepiece.<\/p>\n\n\n\n

For a single all-around eyepiece in a 1.25-inch focuser, this is often the best choice from the series: the largest field of view that still fits within the baffle, with the full 20mm eye relief.<\/p>\n\n\n\n

\"TeleVue<\/figure><\/figure>\n\n\n\n

72 degrees with a long eye relief<\/h4>\n\n\n\n

The Delos series is designed as a narrower Ethos field of view with more space behind the eyepiece. By keeping the field of view at 72 degrees, TeleVue was able to bring the eye relief to 20mm without the eyepiece becoming unmanageably large.<\/p>\n\n\n\n

For eyeglass wearers, that's the difference between seeing the full field of vision and missing a part of it. Even without glasses, you're looking more relaxed because your eye doesn't have to push against the lens.<\/p>\n\n\n\n

The 1.25-inch limit<\/h4>\n\n\n\n

A 1.25 inch diaphragm allows for a field stop of approximately 27mm maximum. At 21.7mm, this eyepiece utilizes a good portion of that without the severe vignetting that occurs at the extreme.<\/p>\n\n\n\n

If you want to continue, a 2-inch eyepiece is needed. Within the series, that is the 24mm Delos.<\/p>\n\n\n\n

Interpupillary distance and adjustable eyecup<\/h4>\n\n\n\n

The eyecup is steplessly adjustable in height and lockable in any position, with index markings so you can find a previously found position. This ensures your eye's pupil is always in the same position relative to the telescope's exit pupil.<\/p>\n\n\n\n

That's more than comfort. A misplaced eye causes edge discoloration and shadows in the image. With a fixed, repeatable eye position, that problem is gone, even during long sessions.<\/p>\n\n\n\n

In your telescope<\/h4>\n\n\n\n

In a telescope with a 1200mm focal length, this eyepiece provides approximately 69x with a true field of view of about 1.04 degrees. For your own telescope, you calculate that using the field stop: true field of view = 57.3 x field stop divided by the focal length of the telescope.<\/p>\n\n\n\n

The effective field stop of this model is 21.7 mm. That number determines how much sky you actually see, not just the focal length.<\/p>\n\n\n\n

Included<\/h3>\n\n\n\n