Research Grade TZ-3 Telecentric System (3x focal length)

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Research Grade TZ-3 Telecentric System (3x focal length)

# 2459257

€ 395.00 Price excl. German VAT tax (19%): € 331.93
  • Research Grade Telecentric Unit, featuring an oversized pick up expanding lens set and 2" (50.8mm) threads on both sides – T-2 Adapter and 2" m/f inverter ring are both included as standard accessories
  • 46mm clear aperture at the H-alpha-filter entrance side - suitable for research grade SolarSpectrum H-alpha filters
  • Large working distance of 250mm for optimized focal length reduction with a telecompressor and suitable room for adapting a binocular viewer
  • Aplanatic, with 3x focal length extension to achieve a parallel f/30 beam in conjunction with ~f/10 optics systems – free of field curvtare
  • Primarily calculated and produced for H-alpha at 656,3 nm, delivering 99% Strehl (99% definition brightness )
  • Diffraction limited design also at 396 nm (CaK)

Product Questions

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If using the TZ-3 with a 32mm CA SolarSpectrum ASO model is some light lost since the TZ-3 is designed to produce a 46mm output beam? If 'yes', light is lost, when used with a 32mm etalon can the rear lens of TZ-3 be moved closer to the front / input lens to produce an exit beam more closely matched to the 32mm CA of the ASO model Ha filter and thus produce a brighter image in an eyepiece?
Question by: Anthony Sarra on Mar 12, 2017 7:25:00 AM | 1 Answer(s)
A couple of followup questions. 1) I noticed the TZ-3 tube has 3 'sections' longest being in front, shortest at rear holding 'collimation'/'pickup' lens and a middle section that appears to be just a spacer. Can the middle section be removed (omitted) such that rear lens becomes closer to front 'input' lens.
2) Is the middle section intend for removal to provide for an alternate closer location of pickup lens or is this just a manufacturing convenience to be a separate part (reuse of existing parts?)?
3) What would be the characteristics of the resulting output beam? Diameter, F#, impact on position of TZ relative to main objective (assume that would not change), impact on distance from TZ to final focal plane which was originally 250mm?
Question by: Anthony Sarra on Mar 12, 2017 8:05:00 PM | 1 Answer(s)
Can the Baader Telecentric lenses be used like ordinary Barlows, e.g. for visual observation or imaging (from UV to IR) of the planets?
Question by: Jack on Feb 10, 2017 7:21:00 AM | 1 Answer(s)


Baader Telecentric Systems for focal length extension

for supplying a parallel optical beam and for providing sufficient backfocus, in conjunction with any SolarSpectrum H-alpha filter

Telecentric optics sets are often confused with a barlow lens. Both can be used to increase the focal length. Telecentric assys are designed so that the exit pupil seemingly is positioned at infinity, which means that the center ray from any point in the field appears to come from infinity and is therefore perpendicular to the image plane and parallel to the optic axis. This means that the off axis beam does arrive at the image plane with the same angular geometry as the axial rays. All field elements look as if they where on axis, across the image plane and - unlike to a barlow lens - the edge field rays are not tipped bundles.

Because all the principal rays across the image plane are perpendicular to the image plane, the rays at the edge of the field will pass through an etalon just in front of the focal plane with exactly the same geometry as the rays on axis. So in an f/30 telecentric optical arrangement, the etalon sees the exact same geometry clear across the field, and the spectral bandpass does not shift in wavelength across the entire field of view.

Starting from an aperture ratio of ~f/15 (+2x Telecentric), ~f/10 (+3x Telecentric) or ~f/7.5 (+4x Telecentric), the Baader TZ-systems will create a parallel beam with ~f/30 aperture ratio. In the case of largely deviating telescope focal lengths, the clear objective aperture of the telescope should be reduced in diameter to the point that the final resulting f/ratio is close to f/30 again (we do offer a suitable iris-diaphragm for this purpose).

TZ-system working distances – when measured from their rear lens – range from 200mm for the TZ-2 to 230 mm for the TZ-4 - to 250 mm for the TZ-3. This provides enough room for the H-alpha filter housing and most any accessories, e.g. a Baader 2" mirror diagonal or any conceivable camera device. The generous room of the TZ-3 will also accommodate a binocular viewer when it is mounted onto the SolarSpectrum body by means of 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. Still the TZ-3 especially also works for CaK at 396 nm. The TZ-3 Strehl-ratio is well above 80% at 396 nm

Please also note the detailed PDFs under the Tab "Downloads" for further information


Additional Information

Manufacturer Baader Planetarium
SKU (#) 2459257
Weight (kg) 0.37
Focal length extension 3x
Usage for H-alpha observation with SolarSpectrum filters
Inner Connection (lens sided) Thread, T-2 (M42 x 0,75), 2"
Outer Connection (lens sided) Thread, 2"
Outer Connection (eyepiece/-camera-sided) Thread, T-2 (M42 x 0,75), 2"

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