Astro-Physics 305mm F3.8 Riccardi-Honders Astrograph

ASTRO-PHYSICS
305mm F/3.8 Riccardi-Honders Astrograph

History of the Riccardi-Honders Design

This telescope is the first of its kind. 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 our 30+ years of telescope design experience to create a truly unique and fast astrograph to take full advantage of today's CCD imaging cameras. Imagine how quickly you will collect photons for the wide-field images that you plan to shoot.

Astro-Physics Version

The Astro-Physics design is a modification of the Riccardi-Honders. It 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), is fully corrected for all 5 Seidel aberrations (spherical, coma, astigmatism, field curvature and distortion), as well as longitudinal and lateral chromatic aberration. Multi-coatings on all optical elements ensure very high-contrast images.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. Consider these advantages:

Optics and tube designed for stable focus. 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.
All elements are held rigidly in place and cannot move.
Fast optical design optimizes your imaging sessions by gathering photons quickly.
Substitute electronic focuser, if you wish.
Vented rear cell for rapid temperature stabilzation.

The 305mm f/3.8 Riccardi-Honders Astrograph prototype was introduced at the Northeast Astronomy Forum (NEAF) on April 18, 2009. It was shown with the 305mm f/12.5 Maksutov-Cassegrain prototype on our 3600GTO German Equatorial Mount. Roland Christen had discussed the advantages of the Riccardi-Honders optical design in his presentation entitled "Optical Design for High Resolution Imaging" at NEAF the prior year, so it was fitting that we chose this venue to introduce our newest telescope.

The Results Speak for Themselves!

Click the links below to view Roland's images taken with the 305mm f/3.8 Riccardi-Honders Astrograph from our light-pollluted suburban location..

NGC7000 - North American Nebula (Hubble Palette)		Lower Right Crop from NGC 7000

Crescent Nebula in Milky Way - Two-Frame Mosaic


Spiral Galaxy M106		Center Crop of M106

M81 and M82


NGC 7822 at Half Resolution (to fit your monitor)	Crop #1 from NGC 7822 - "guppies"	Crop #2 from NGC 7822 - "fingers"
Click here for the full resolution, 3326 x 2504 pixel image! (File is over 1 MB.)

Specifications

Clear aperture	12" (305mm)
Secondary mirror size	5.9" (150mm)
Focal length	45.6" (1159mm)
Focal ratio	f/3.8, Airy disc size 5 microns
Field size	Diffraction-limited over 3.0 degree field - 60mm circle
Tube assembly	14" (36cm) diameter x 21" (53cm) long, focuser adds 4" (10cm). 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.
Dewcap	Machined aluminum dewcap, internal baffles as well as curved front edge baffle, black interior
Mounting rings	Machined aluminum rings, ribbed to reduce weight, felt-lined Bottom of rings: 1/4-20 tapped holes, spacing: 2.362", 3.20", 4.5" and center hole Top of rings: 10-32 tapped holes spaced 3.00" and 1/4-20 center hole
Weight	Tube with focuser, without dewcap: 58 lbs (26.2 kgs) Dewcap: 7 lbs (3.2 kgs) Dustcover: 3.0 lbs (1.6 kgs) Rings: 2.5 lbs (1.1 kgs) each
Diameter of corrector cell	14.50" (368.3mm)
Focuser (removable)	3.5" ID Focuser, rack and pinion with FeatherTouch Micro 9:1 dual-speed reduction, 1.25" (31.8mm) travel, 2.7" and 2" adapters
Back focus	With 3.5" Focuser: 3.95" (100mm) from focuser housing (no adapters) Without Focuser: 6.38" (162mm) from backplate (when focuser removed)
Mirror coating	96% enhanced and protected aluminum
Corrector coating	Broadband multi-coatings both sides
Carrying case for main tube of telescope	Dewcap does not fit in case.

What's Included?

305mm f/3.8 Tube Assembly with 3.5" Focuser, Dewcap and Dustcover
14" Mounting Rings, pair
Carrying Case

Price and Delivery Information
We typically maintain notification lists so that we can notify prospective customers when the scope is available to order. Please refer to our availability page for more information on our notification lists. If you are interested in the 305mm Riccardi-Honders Astrograph and are not already on the notification list for this instrument, you can sign up on our online notification form. An automatic confirmation e-mail will be sent to you for your records. Refer to Notification Update periodically to find out the status of our mount and telescope production runs - what we are making throughout the year.

Price: $22,420
Please note that the Riccardi Honders is shipped on a pallet in order to assure its safe arrival. There will be additional charges for the pallet and shipping.

Recommended Accessories and Options

There are many other accessories to consider. Please refer to these sections for additional recommendations:
1600GTO German Equatorial Mount
1100GTO German Equatorial Mount
Visual Accessories
Photographic and CCD Imaging Accessories
Baader Planetarium Filters
Mounting Plates - your choices will be determined by the mount you own.

Specifications subject to change without notice.

Astro-Physics, Inc.
11250 Forest Hills Road, Machesney Park, IL 61115, U.S.A.
Phone: 815-282-1513 Fax: 815-282-9847