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Dall-Kirkham 8", 10" , 12.5", 14.5" and 16"
Optical Tube Assemblies
I am now offering three standard optical tube assemblies featuring Dall-Kirkham optical systems. These are serious telescopes of excellent mechanical and optical quality hand-made by me and designed exclusively for the finest high-resolution lunar, planetary and double star astronomy. The functional, no-nonsense designs are the result of years of work developing an uncomplicated and attractive tube assembly, the optics are the result of many years of study in design and proprietary fabrication techniques, and the overall result is an aesthetic and functional balance that gives you the most in great observing for your money. Significant design features include my unique curved vane spiders that completely eliminate any visible diffraction spiking. Analysis has shown that a properly designed curve vane spider contributes less diffraction than a Maksutov corrector when typical design and fabrication errors are considered; so, you get the same performance without the added weight and cost. There is no expense and weight-adding motorized secondary focuser. Convenient accommodation is made at the focuser for varying in-focus requirements, and keeping the secondary mirror uncomplicated and light in weight means I can create a delicate curved vane spider - not so mechanically robust but far less diffraction producing than some of the thick, heavy-weight, spike-makers out there. If you want refractor-like performance you can't go cluttering up the light path with huge obstructions, projections and thick vanes. Obstructions need to be small and clean. (By the way, everything we look at in space is at infinity - once adjusted, you're adjusted for all objects, so motorized secondaries are not really necessary.)
These telescopes are not compromise instruments designed for general observing and focal ratios of 20 are not for deep-sky astronomy (though M13 will look wonderful) but, with their small obstructions and large image scale, they are wonderfully suited to lunar, planetary or double star work and have the advantage of a short tube and convenient sit-down observing.
The essence of these telescopes is simplicity and functionality. They are for advanced observers and imagers and have been designed work efficiently and without inconvenience to the user. The inherent simplicity of the overall design means that there is little to become deranged or fail at that critical moment. The fundamental rigidity of the Surrier truss and the method of mounting and holding the conical mirror insure that there is no mirror shift and consequent image shift. While these telescopes may not have a romantic or awe-inspiring name, they do have a name-plate at the back with a number and a makers mark personally engraved by me.
Concerning the 14.5" and 16" sizes, the 16" has been prototyped and the first telescope delivered. These telescopes are constructed out of aluminum similar to the 12.5" models but with a different and lighter backplate and overall lighter construction. Total weight is 95 lbs for the 16" and about 75 lbs for the 14.5". These OTAs are to be portable in the sense that the tube will separate easily into two approximately half-tube length sections for easier transport and set-up.
Things that make these telescopes different
Operational Features
Small secondary obstruction and a curved vane spider
Smooth and stable collimation
General
construction - new design aluminum U-channel struts
Mounting plate
and mount attachment
Accessories
The Telescope Bag - a complete and heavy duty, quick on and off, zippered cover
Air turbulence lower cover - keeps warm body air away from light path
8"
Dall-Kirkham
Telescope comes with either carbon fiber or aluminum tube. For
all observing except long-period imaging an aluminum tube is sufficient and
weighs very little more than a carbon fiber tube.
10"
Dall-Kirkham Telescope comes
with either carbon fiber or aluminum tube. For all observing except long-period
imaging an aluminum tube is sufficient and weighs very little more than a carbon
fiber tube.
12.5"
Dall-Kirkham
16"
Dall-Kirkham
1. Upgradable to
autofocuser configurations
Telescope:
RFR-DK08420
Optical Tube Assembly
Aperture
- Obstruction:
8"
- 2" (25%)
Focal
Ratio of Primary:
4
Effective
Focal Ratio:
22.5
- 180"
Length
of Tube - Weight:
32"
- 25 lbs
Optical
Design:
Dall-Kirkham
reflector
Tube
- Mounting Method:
Solid
wall carbon fiber
or aluminum
- Parallax Rings3
Back
Plate and End Rings:
Machined
aluminum
Tube
Current Control:
2"
exhaust fan and filter inlet port
Spider:
Curved
vane
Exterior
Finish:
Metal
parts powder coated semi-gloss black.
Focuser
- Travel:
Moonlight
CR Newtonian Focuser1 - 2"
Available
Backfocus:
4"
additional infocus available using adjustable extension tube
Finder:
60
mm Stellarvue2
PRICE:
With
carbon fiber tube $3,800
With aluminum tube $3,400
Shipping:
At
cost FedEx ground (approx. $80)
Availability
6
to
8 months.
Additional
Pictures
Telescope:
RFR-DK10420
Optical Tube Assembly
Aperture
- Obstruction:
10"
- 2.5" (25%)
Focal
Ratio of Primary:
4
Effective
Focal Ratio:
20
- 200"
Length
of Tube - Weight:
40"
- 30 lbs
Optical
Design:
Dall-Kirkham
reflector
Tube
- Mounting Method:
Solid
wall carbon fiber or aluminum - Parallax Rings3
Back
Plate and End Rings:
Machined
aluminum
Tube
Current Control:
2"
exhaust fan and filter inlet port
Spider:
Curved
vane
Exterior
Finish:
Metal
parts powder coated semi-gloss black.
Focuser
- Travel:
Moonlight
CR Newtonian Focuser1 - 2"
Available
Backfocus:
4"
additional infocus available using adjustable extension tube
Finder:
60
mm Stellarvue2
PRICE:
With
carbon fiber tube $5,400
With aluminum tube $4,800
Shipping:
At
cost FedEx ground (approx. $100)
Availability
Usually
in about 3 to 6 months.
Telescope:
RFR-DK125420
Optical Tube Assembly
Aperture
- Obstruction:
12.5"
- 3" (24%)
Focal
Ratio of Primary:
4
Effective
Focal Ratio:
20
- 250"
Length
of Tube - Weight:
48"
- 51 lbs
Optical
Design:
Dall-Kirkham
reflector
Tube
- Mounting Method:
Surrier
truss, aluminum - Dovetail attached to mounting plate
Back
Plate and End Rings:
Machined
aluminum
Tube
Current Control:
Open
truss, natural ventilation
Spider:
Curved
vane
Exterior
Finish:
Metal
parts powder coated silver vein and semi-gloss black.
Focuser
- Travel:
Moonlight
CR Newtonian Focuser1 - 2"
Available
Backfocus:
4"
additional infocus available using adjustable extension tube
Finder:
60
mm Stellarvue2
PRICE:
$9,600
Shipping:
At
cost FedEx ground (undetermined)
Availability
Usually
in about 6 to 8 months.
Telescope:
RFR-DK16418
Optical Tube Assembly
Aperture
- Obstruction:
16"
- 4" (25%)
Focal
Ratio of Primary:
4
Effective
Focal Ratio:
18
- 288"
Length
of Tube - Weight:
70"
- 95 lbs
Optical
Design:
Dall-Kirkham
reflector
Tube
- Mounting Method:
Surrier
truss, aluminum - Dovetail attached to mounting plate
Back
Plate and End Rings:
Machined
aluminum
Tube
Current Control:
Open
truss, natural ventilation
Spider:
Curved
vane
Exterior
Finish:
Metal
parts powder coated gold or silver vein and semi-gloss black.
Focuser
- Travel:
Moonlight
1 - 2.5" refractor focuser
Available
Backfocus:
4"
additional infocus available using adjustable extension tube
Finder:
60
mm Stellarvue2
PRICE:
$16,000
Shipping:
At
cost FedEx ground (approx. $200)
Availability
Usually
in about 3 to 8 months.
2. Upgradable to 80
mm Stellarvue for $100
3. Must be ordered separately. Not included with telescope or as part of price.