The I3 Piece Technical Questions and Answers


Q. What is the I 3 PIECE (also called I Cubed) ?

A. The I 3 PIECE(which stands for Intensified Generation 3 Eyepiece) combines the leading edge of Image Intensified Technology with state of the art optics and optical adapters in a compact package that operates with any telescope using 1.25 " or 2" removable eyepieces.

Q. How does it work?

A. At the heart of the system is an ITT NIGHT VISION Generation 3 Image Intensifier tube that amplifies the light focused on its input window from the telescope. The telescope image is amplified or intensified by approximately 50,000 times. (For detailed information on image intensifier technology ( . The amplified image is displayed on the rear or output end of the tube called the phosphor screen, which can be seen when the optical attachments are un-threaded from the rear of the tube housing. It is this greatly amplified image that is coupled to either your eye, a 35mm camera or a CCD camera or video.

Q. How does one use these various attachments on the I 3 PIECE ?

A. Let’s talk about the I 3 PIECE adapter which is the cornerstone of the system.

1) I3 Piece with 25mm eye lens and 2" telescope adapter.
2) With 25mm eye lens and 1.25" telescope adapter.
h_eyepiece.jpg (10429 bytes)


Using the I 3 PIECE adapter is very straightforward, all of the attachments are threaded to match the I 3 PIECE adapter thread on its output end. All attachments have a stop or locating ring to facilitate their focal point location when removed and reattached. (For details on each attachment click on their buttons at the top of the page.)

Q. How much detail is present in the amplified image displayed on the image intensifier phosphor screen ?

A. A tremendous amount,in fact the tube image is capable of displaying resolutions up to 64 line pairs per millimeter, that is .00062 inches or .016mm per line pair! (There are 1120 line pairs across the l8 mm phosphor screen.

Q. How does this compare with a CCD camera?

A. The technologies are substantially different, making a direct comparison difficult. Let’s consider resolution as our basis of comparison. Most commercially available CCD cameras have pixel sizes between 9 and l8 microns (.009mm to .018mm) . If we use critical sampling (also called the Nyquist limit) which is 2 pixels across the resolution element, then we have .018 to .036mm for our minimum sample. Remember that our image intensifier resolution is .016 per pair making individual element resolution of the image intensifier output phosphor screen as good as or even better than CCD camera performance. This is due in part to the recent amazing advances in ITT NIGHT VISION image intensifier performance. For example the micro channel plate pore size used in the I 3 PIECE system is 6 microns.

Q. How does the actual image capturing ability compare between the I 3 PIECE and CCD cameras?

A. The most important difference is that the I 3 PIECE is a real time device, the CCD camera is not. The image on the I 3 PIECE phosphor screen is useable optically without any interface , whereas the CCD must gather light over some period of time and requires a computer interface. The CCd camera actually has greater sensitivity to low light but over a much greater period of time.

Q. So What can I see when I use the eyepiece attachment?

A.To sum it up, you can see more with the I3 PIECE than your dark adapted eyes under any circumstances using the same telescope with any conventional eyepiece. Any nebula or galaxy that you would normally see as a dim smudge of light (often using averted vision) becomes an easily seen object with no eye strain. In fact many amateur astronomers who have reduced night vision acuity will find that the I 3 PIECE makes visual astronomy a great pleasure.

Q. How are the deep sky objects seen in the Sky and Telescope advertisement and the web site imaged?

A. Using the I Cubed with Nikon 990 Digital Camera Adapter and 7 inch F9 Astro Physics refractor in suburban backyard conditions.


Q. Does the I3 PIECE system respond to radiation outside the visible spectrum?

A. Most definitely! In fact the spectral response extends all the way to 900 nanometers, meaning that you can image deep sky objects with details in the infrared that are invisible to conventional optical instruments.

Q. What materials are the system components fabricated from and how are they made?

A. All cylindrical components that incorporate optics or electronics including adapters are 6061 T6 aluminum, hard black anodized. These components are fabricated on multi axis CNC machinery.

Q. Tele Vue optics are mentioned in the Sky and Telescope advertisement, where are they used in the I3 PIECE system?

A. When we decided to produce the I3 PIECE system, we concluded that compromise was unacceptable. This is true of the optics from Tele Vue. The eyepiece adapter and video/CCD relay adapters use Tele Vue optics because they provide the best performance. (