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TeleVue 17.3mm Delos Eyepiece


The 17.3mm Delos was the newest eyepiece from TeleVue as of March 2012. This is a focal length applicable to a broad variety of telescopes, which explains why TeleVue now offers three choices in this approximate focal length. Owners of f/10 Schmidt-Cassegrains will enjoy the bright 1.7mm exit pupil while viewing deep space objects. Owners of the ubiquitous 1200mm class Dobsonians will enjoy a true field of just over one full degree.


Item #ProductStock StatusPriceShipping
EDL-17.3TeleVue 17.3mm Delos
In Stock - Ships Same Day (business days) This is "live" inventory data. If it says in stock, you can believe it.
$315.00
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TeleVue 17.3mm Delos Eyepiece

Introducing 17.3mm TeleVue Delos Eyepiece

The Delos was conceived as a narrower field Ethos. Reducing the field to 72 degrees allowed freedom to increase eye relief, while controlling pupil aberations, all without making the eyepiece too large. With Ethos performance standards as benchmarks, the Delos design achieves full field sharpness, virtually perfect theta distortion mapping, and color neutrality.Image fidelity is maximized utilizing glass matched multi-coatings and anti-reflection surfaces throughout the eyepiece.

Contrast is further enhanced with a new, continuously adjustable height eyeguard system that can be locked in any position. Since the Delos eye-lens measures a quite large 35mm in diameter, preventing stray light from reflecting off the first surface and extraneous light from entering your eye pays off in a nice increase in perceived contrast. The eyeguard's sliding action allows for positioning the soft rubber eyeguard at the ideal height to suit the observer's preference. Indicator marks on the eyepiece body are handy reference guides for setting your perfect position. The eye-guard can also rotate for Dioptrx users.

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Optical Specifications: TeleVue 17.3mm Delos
Focal Length 17.3 mm
Apparent Field-of-View 72°
Eye Relief 20 mm
Physical Parameters
Weight 14.4 Ounces
Barrel Diameter 1.25 Inches
Eyepiece Calculator
Enter at least two of your telescope's specifications:
*Focal Length (mm):
*Aperture (mm):
Focal Ratio (f/):
Magnification:
 
True Field:
 
Exit Pupil: <p>Exit pupil represents the diameter of the column of light exiting the eyepiece.  Magnification is simply the ratio of telescope aperture to exit pupil.  Fox example, using a telescope with 100mm aperture and an exit pupil of 2mm yields a magnification of 50X.</p>

<p>There are both upper and lower limits to the useful range of exit pupils.  The typical human eye pupil dilates to a maximum of 7mm when fully dark adapted.  This figure decreases with age.  Using an exit pupil that is larger than this upper limit simply spills the light onto an area of the eye not capable of receiving data.  At the opposite end of the range, a smaller exit pupil means less area on the eye is collecting data.  Images brightness decreases with decreasing exit pupil. Deep space objects grow dimmer rapidly as the exit pupil falls below 1 mm. The planets also start to become noticeably dimmer when the exit pupil falls much below 0.5 mm.</p>

<p>Our eyepiece calculator provides warnings and error messages based upon the value of the exit pupil.  These are intended to be guidelines as opposed to hard rules. There is no harm in violating these gidelines, but your enjoyment of the telescope may be diminished if you do. </p>