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:

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..
NGC 7000- North American Nebula Crop from NGC7000  
NGC7000 - North American Nebula (Hubble Palette) Lower Right Crop from NGC 7000  
Crescent Nebula in Milky Way - two part mosaic
Crescent Nebula in Milky Way - Two-Frame Mosaic
Spiral Galaxy M106 Spiral Galaxy M106  
Spiral Galaxy M106 Center Crop of M106  
M1 and M82
M81 and M82
NGC 7822 Crop from NGC7822 Crop #2 from NGC7822  
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.)  


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.


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


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? 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.

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Copyright 2010-2106 Astro-Physics Inc. All rights reserved.
Last modified: May 10, 2018

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