Hubble 10, 12.5, 17, 20-inch CDK (Corrected Dall-Kirkham), and
beyond:

The SCT has been the industry-standard visual, film and small CCD imaging
telescope for popular astronomy since the mid-70s.  However, the standard
SCT has a highly curved focal surface and suffers from considerable comatic
aberration, which limits its
useful photographic field to a relatively small image circle. For instance, a
10” all spherical SCT can provide 10-micron spot sizes over only a very small
field of about 9mm diameter, which is clearly not suitable for today’s high
resolution, large format CCDs.  The Hubble corrected Dall-Kirkham (CDK)
optical configuration, as developed over the last 13 years by Dave Rowe, is
a revolutionary optical design that overcomes these limitations.  It is an
affordable, high performance solution for astrophotography and visual use,
with a large, flat focal surface that is perfect for modern, high resolution,
CCD cameras.

Hubble CDK significantly outperforms many other popular designs, including
Ritchey Chretie.  In particular, the CDK design is much easier to align and
collimate than Ritchey Chretie.  Combined with our revolutionary sandwich
primary,  Our CDK 10" and 12.5" optics will bring you superior optical
performance in real world situations, even without an active cooling system
(Active cooling systems, such as fans, introduce their own serious problems,
such as micro vibration, which will degrade the image quality more or less).
Our mirrors reach equilibrium extremely fast, and without aid.
Hubble CDK10 f/8 Specification:

System Focal Ratio: 8
Field Of  View: 45mm
Obstruction Ratio:  38%
Back Focus (from the last surface of the corrector lens): 253mm
Suggested Focuser Diameter: 2"

Primary Mirror:
Optical Diameter: 254mm  (overall diameter 266mm)
Weight: ~4kg
Thickness: ~45mm
Focal Ratio: f/3
92% Semi-enhanced coated
Strehl Ratio 0.95 or better.

Secondary Diameter: 95mm
96% enhanced coated.

Corrector Optics:
99.5% broadband coated.

Delivery Time: ~90 days

CDK 10 f/8 Optics Only (Primary mirror, Secondary mirror and Corrector Lenses ):
$1200 + S&H  (Plate Glass Primary)
$1600 + S&H  (Pyrex Primary)



Hubble CDK12.5 f/8 Specification:

System Focal Ratio: 8
Field Of  View: 60mm
Obstruction Ratio:  42%
Back Focus (from the last surface of the corrector lens): 318mm
Suggested Focuser Diameter: 3"

Primary Mirror:
Optical Diameter: 317.5mm  (overall diameter 334mm)
Weight: ~6kg
Thickness: ~40mm
Focal Ratio: f/3
92% Semi-enhanced coated
Strehl Ratio 0.95 or better.

Secondary Diameter: 120mm
96% enhanced coated.

Corrector Optics:
99.5% broadband coated.

Delivery Time: ~90 days

CDK 12.5 F/8 Optics Only (Primary mirror, Secondary mirror and Corrector Lenses ):
$1950 + S&H  (Plate Glass Sandwich Mirror)
$2495 + S&H  (Pyrex Glass Sandwich Mirror)
*The ACF data is based on the public information released by the Star-RC
vs. Meade.
The CDK12.5 primary mirror is made with our revolutionary sandwich mirror.
The CDK10 is made with plate or Pyrex solid blank.

Our 2-section (completely CNC machined) closed tube OTA  prototype is not
only optimized to reach a zero thermal focal shift, but is also structurally
much stronger than a single section tube.
Hubble CDK17 f/6.8 Specification:
System Focal Ratio: 6.8
Field Of  View: 60mm
Obstruction Ratio:  39%
Back Focus (from the last surface of the corrector lens): 341mm
Suggested Focuser Diameter: 3"

Primary Mirror:
Optical Diameter: 432mm
Weight: ~13kg  (Plate Glass),  ~12kg (Pyrex)
Thickness: ~55mm
Focal Ratio: f/3
92% Semi-enhanced coated
Strehl Ratio 0.95 or better.

Secondary Diameter: 160mm
96% enhanced coated.

Corrector Optics:
99.5% broadband coated.

CDK 17 Optics Only (Primary mirror, Secondary mirror and Corrector Lenses ):
$5500 + S&H  (Plate Glass Sandwich Mirror)
$6700 + S&H  (Pyrex Glass Sandwich Mirror)
Delivery Time: ~90 days



























Hubble CDK20 f/6.8 Specification:
System Focal Ratio: 6.8
Field Of  View: 70mm
Obstruction Ratio:  39%
Back Focus (from the last surface of the corrector lens): 341mm
Suggested Focuser Diameter: 3"

Primary Mirror:
Optical Diameter: 500mm
Weight: ~20kg  (Plate Glass),  ~18kg (Pyrex)
Thickness: ~55mm
Focal Ratio: f/3
92% Semi enhanced coated
Strehl Ratio 0.95 or better.

Secondary Diameter: 188mm
96% enhanced coated.

Corrector Optics:
99.5% broadband coated.

CDK 20 Optics Only (Primary mirror, Secondary mirror and Corrector Lenses ):
$8000 + S&H  (Plate Glass Sandwich Mirror)
$9500 + S&H  (Pyrex Glass Sandwich Mirror)
Delivery Time: ~90 days
























Hubble CDK24 f/6.8
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Hubble CDK28 f/6.6
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Hubble CDK36 f/6.5
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Hubble CDK40 f/6.5
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CDK17 OTA with EQ Mount designed by Stephen Mounioloux
Hubble CDK17 OTA