Baader Planetarium Research Grade TZ-3 Telecentric System (3x Focal Length)

How does the Research Grade TZ-3 Telecentric System revolutionize your optical experience This system, designed to work in harmony with any SolarSpectrum H-alpha filter, delivers a parallel optical beam and provides ample backfocus. Unlike a barlow lens, which is often confused with telecentric optics sets, the TZ-3 Telecentric System is engineered to position the exit pupil at infinity. This unique design ensures that the center ray from any point in the field appears to originate from infinity, making it perpendicular to the image plane and parallel to the optic axis.

The result An off-axis beam that arrives at the image plane with the same angular geometry as the axial rays. This means that all field elements appear as if they were on axis, across the image plane. Unlike a barlow lens, the edge field rays are not tipped bundles. This is because all the principal rays across the image plane are perpendicular to the image plane, allowing the rays at the edge of the field to pass through an etalon just in front of the focal plane with the exact same geometry as the rays on axis.

In an f/30 telecentric optical arrangement, the etalon sees the same geometry clear across the field, ensuring the spectral bandpass does not shift in wavelength across the entire field of view. Starting from an aperture ratio of approximately f/15 (+2x Telecentric), f/10 (+3x Telecentric) or f/7.5 (+4x Telecentric), the Baader TZ-systems, including the TZ-3, create a parallel beam with an approximate f/30 aperture ratio.

For telescopes with significantly deviating focal lengths, the clear objective aperture can be reduced in diameter to achieve a final resulting f/ratio close to f/30. The TZ-3 Telecentric System offers working distances ranging from 200mm for the TZ-2 to 230 mm for the TZ-4, and up to 250 mm for the TZ-3, when measured from their rear lens. This provides ample room for the H-alpha filter housing and most accessories, including a Baader 2" mirror diagonal or any conceivable camera device.

The TZ-3's generous room can also accommodate a binocular viewer when mounted onto the SolarSpectrum body using a Baader BBHS T-2 star diagonal. All TZ-coatings are matched to the different lens glass-substrates and optimized for maximum throughput at 656 nm. The TZ-3 is also compatible with CaK at 396 nm, with a Strehl-ratio well above 80% at this wavelength. Experience the difference with the Research Grade TZ-3 Telecentric System.