ASTRO-PHYSICS 305mm F/3.8 Riccardi-Honders Astrograph
The 305mm f/3.8 Riccardi-Honders Astrograph prototype was introduced at the Northeast Astronomy Forum (NEAF) on April 18, 2009.
The design of the Astro-Physics 305mm f/3.8 Astrograph is based on Klaas Honder's original idea of a fast optical system using a crown glass objective and meniscus correcting mirror in a Newtonian configuration. By adding a secondary mirror and field lens, Italian designer Massimo Riccardi was able to design an ultra-fast astrograph using only crown glass elements. Astro-Physics has added 40 years of telescope design experience to create a truly unique and fast astrograph to take full advantage of today's CCD imaging cameras.
The Astro-Physics Ricardi-Honders Astrograph at a glance:
- features diffraction-limited performance over a huge 3-degree field, which is ideal for capturing large faint nebulae over a wide wavelength range
- the design has essentially perfect color correction from 400 to 1000 nanometers (UV to IR)
- the telescope is fully corrected for all 5 Seidel aberrations (spherical, coma, astigmatism, field curvature and distortion), as well as longitudinal and lateral chromatic aberration
- Tube material is a special alloy that maintains the focus almost exactly during wide temperature swings.
- extremely compact and light-weight, perfect for the Astro-Physics 1100GTO German Equatorial Mount
- closed tube and protected mirror coating keep the optical system free from dust, which can cause scatter, reducing contrast..
- Multi-coatings on all optical elements ensure very high-contrast images
- Vented rear cell for rapid temperature stabilzation
- the primary Mangin mirror has a rear reflection surface. This means that the reflective surface has almost no scatter and it will not degrade over the years due to exposure from the air like an ordinary front surface mirror
- 3.5" ID Focuser, rack and pinion with FeatherTouch Micro 9:1 dual-speed reduction, 1.25" (31.8 mm) travel
- Back Focus with 3.5" Focuser: 3.95" (100 mm) from focuser housing (no adapters), without Focuser: 6.38" (162 mm) from backplate (when focuser removed)
- 305 mm f/3.8 Tube Assembly with 3.5" Focuser, Dewcap and Dustcover
- 14" Mounting Rings, pair
- Carrying Case
For further information and useful accessories about the 305mm F/3.8 Riccardi-Honders Astrograph please visit the original Website von Astro Physics. If you are interested, please send us an email to kontakt (at) baader-planetarium.com or call us.
Astro images taken with the ASTRO-PHYSICS 305mm f/3.8 Riccardi-Honders Astrograph:
|Weight (kg)||Tube with focuser, without dewcap: 58 lbs (26.2 kgs), Dewcap: 7 lbs (3.2 kgs)|
|Optical Design||Riccardi Honders|
|Clear Aperture||12" (305 mm)|
|Focal Ratio||f/3.8, Airy disc size 5 microns|
|Back Focus Distance||With 3.5" focuser: 3.95" (100 mm) from focuser housing (no adapters), without focuser: 6.38" (162 mm) from backplate (when focuser removed)|
|Optical Coatings||Broadband multi-coatings both sides, 96% enhanced and protected aluminum|
|Tube (Material)||Focuser adds 4" (10 cm). Closed machined tube, fully baffled, engraved retaining ring, felt-lined dustcover, black-anodized aluminum cells and other components, cream-white pebble finish on the tube. Two handles on backplate.|
|Length of tube||14" (36 cm) diameter x 21" (53 cm) long|
|Optical length (mm)||14" (36 cm) diameter x 21" (53 cm) long|
|Focuser||3.5" ID Focuser, rack and pinion with FeatherTouch Micro 9:1 dual-speed reduction, 1.25" (31.8 mm) travel, 2.7" and 2" adapters|