Visual astronomy using the I 3 intensified eyepiece

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The visual I 3 PIECE is the only product available to the amateur astronomer that provides an intensified ‘real time’ image of deep sky objects. This is made possible by combining ITT NIGHT VISION generation 3 image intensifier technology with advanced patented optics from Tele Vue. The result is an easy to use product that fits into place on your telescope exactly as a standard eyepiece does. From a light gathering standpoint the I 3 PIECE makes any telescope perform as if it were both lower in f# and larger in aperture. For visual astronomers the increase in object intensity with a great reduction in eye fatigue makes the I 3 PIECE unique. The image quality is excellent with sharp star images across the full field of the eyepiece. The image bears no resemblance to the dark green, muddy low resolution image found on inexpensive imported night vision products that are flooding the American market. Customers feel confident knowing that American technology (so sophisticated that US law restricts it’s export) supplied by ITT NIGHT VISION to Collins Electro Optics is used because we will not compromise performance. We use only select specification generation 3 image intensifier tubes in all of our products.

Many amateur astronomers have reduced visual acuity when their eyes are dark adapted (scotopic vision). This is unfortunate since we desire our vision to be at its best during extended observing sessions and in reality our eyes may not perform well for a number of reasons. The I 3 PIECE makes extended duration viewing comfortable with an eye relief of 1.5" (using the 25 mm eyepiece) and immediate image acquisition without the need for holding a steady eye position. In fact even beginning astronomers have no difficulty maintaining a continuous view. There is far less dark adaptation time required when using the I 3 PIECE as comparted to conventional optics. Typical adaptation to the tube image under dark sky conditions is 30 seconds or less. With a signal to noise ratio of up to 21 db, background noise is reduced to a minimum. The image background displays minor scintillation (amplifier) noise when operated in telescopes at f15 and above.

Object brightness versus the background sky brightness (contrast) is fundamental to the success of using image intensification technology for astronomy. Historically this has been a shortcoming of attempting to use low signal to noise ratio, low resolution intensifiers for visual astronomy because they produce such a noise filled image that the contrast difference between the deep sky object and the sky is reduced to nearly zero. High signal to noise ratio and high photo response in the I 3 PIECE make it possible to see subtle details in many deep sky objects that would be invisible with conventional optics.

The phosphor image screen (which is what the observers eye is focused on during use) has an output wavelength of 530 nanometers and is monochromatic. The degree of green image produced by the I 3 PIECE is subtle under dark sky conditions and the brain adapts rapidly to low level monochromatic images giving the impression of a black and white image after several minutes of use. Higher levels of skyglow from light polluted skies produce more green response, which most observers find reasonable considering the conditions under which the product is being used.

Frequently, potential customers ask about an increase in performance when comparing the I 3 PIECE to conventional optics. The answer depends greatly on the conditions under which the product is used. High urban levels of skyglow combined with increased humidity will reduce the contrast difference between astronomical objects and the sky to zero for all but the brightest starts, some planets and the moon. Under these conditions, the I 3 PIECE (with it’s infrared extended sensitivity) will make many objects visible particularly star clusters, oblique galaxies (NGC 4565 for example) and many nebulae that are not visible or are marginally visible with conventional optics at very low contrast levels. Under dark sky conditions the I 3 PIECE performs superbly, please read the technical paper "Real time observation of stellar and galactic sources using a third generation image intensified optical system" for details on the product’s performance with deep sky objects. Please call us with any technical questions you may have, we would enjoy talking to you.

  

SPECIFICATIONS

For I3 Piece Technical Drawings Click Here

 

WEIGHT: 16.5 OZ./468 GM.(25MM EYEPIECE)

CONSTRUCTION: 6061T6 ALUMINUM, BLACK ANODIZED, INSTRUMENT GRADE FINISHING

OPTICS: TELEVUE PATENTED DESIGN MOUNTED IN COLLINS PROPRIETARY THREADED ADAPTERS

EFFECTIVE FOCAL LENGTH: 25MM

OUTPUT PHOSPHOR SCREEN F.O.V.: 35 DEGREES WITH 25MM EYEPIECE, EYE RELIEF: 1.5"(38 MM)

TELESCOPE ADAPTER: 1.25", WITH FILTER THREAD OR 2.00" (INTERCHANGEABLE)

IMAGE INTENSIFIER: ITT GENERATION 3 /18 MM, SELECT GRADE, ITT THIN FILM PHOTOCATHODE

GAIN: FACTORY ADJUSTABLE 30,000 TO 50,000

RESOLUTION: 64 LP/MM

S/N RATIO: 23 dB NOMINAL TO 30 dB

SPECTRAL RESPONSE: 450-900 NANOMETERS

FULL OUTPUT BRIGHTNESS LEVEL ON PHOSPHOR SCREEN: 2.1 FOOTLAMBERTS

PHOTOCATHODE: GALLIUM ARSENIDE

HALO DIAMETER (MAX): 1.47MM

PHOTO RESPONSE SENSITIVITY: 1500 NOMINAL

NOMINAL TUBE LIFE:10,000 HOURS

OUTPUT WINDOW: FIBER OPTIC

SCREEN SPOT SIZES (DARK ONLY): CALL

BATTERY TYPE: EL123AP (3V LITHIUM)

BATTERY LIFE: 30 TO 50 HOURS TYPICAL

 

CONFIGURATIONS

The I3 body is threaded at both ends to accept a variety of input and output optics.For the input (photo cathode side) one may select the 1.25" or 2" telescope adapter (interchangeable) as standard.An optional adapter for 35mm camera lenses is also available (ideal for meteors).The output (visual side) will accept either the 25mm or 15mm proprietary eyepieces (select either one as standard).Your existing eyepieces will not work with the I3 Piece.The 15 and 25mm eyepieces are interchangeable and may be purchased seperately.Select from one of the following 4 standard configurations .

1) 1.25" telescope adapter/15mm eyepiece.

2) 1.25" telescope adapter/25mm eyepiece.

3)2.00" telescope adapter/15mm eyepiece.

4)2.00" telescope adapter/25mm eyepiece

 

 Collins Electro Optics 9025 E.Kenyon Ave.Denver CO 80237 303-889-5910,FAX 303-779-8496 (9-5 M-F)