DAVID LUKEHURST

ASTRONOMICAL TELESCOPE MAKER

Astronomical Telescopes for the Discerning Observer

"Ultra-Portable" Telescopes

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The "Type 2", pictured below is a refinement of the initial "Type 1" design and has some useful advantages. The "Type 2" telescope assembly can be completed before the altitude bearings are attached which makes balancing of the telescope during construction much simpler. Both mirrors are also better shielded and protected than in the "Type 1" design.

The altitude bearings are removable for transportation or storage and the overall height of the dismantled lower assembly can be less than in the "Type 1" design with the folding altitude bearings. Due to the welded steel construction of the main mirror cell of the Type 1 (the main mirror cell forms part of the mechanical structure of the telescope) the Type 2 is also a little lighter than the Type 1

Although I am still willing to make the Type 1 and Type 1/2 Ultra Portables (see below), it is currently my intention only to make the Type 2 Ultra-Portable Telescopes unless particularly requested. The prices in the price list are for the Type 2 Ultra Portable.

Having now made many more "Ultra-Portable" telescopes, I have also decided that in future I will normally build them with four truss-tube pairs rather than only three. This will improve the rigidity of the telescope and will also simplify construction.

 Ultra-Portable Telescope Type 2

22-inch f/3.6 "Type 2" Ultra-Portable (with Encoders for DSC's)

Altitude Bearings and Altitude Optical Encoder

22-inch dismantled

Dimensions of dismantled lower assembly (mirror box, rocker-box and ground-board: Approx 710mm (L) x 745mm (W) x 385mm (H)

Ultra-Portable Telescope Type 1

This is the first of the Ultra-Portable versions of my telescopes. This design has been replaced by the "Type 2"  although I will still make this design if specially requested. The mirrors are poorly shielded in this design and the main mirror cell and altitude bearings form part of the mechanical structure of the OTA which makes construction more difficult.

This design has the aim of making the telescope as light and easy to transport as reasonably possible and as small as possible when dismantled for transportation/storage. If this is a critical factor, this design is the one to go for.

This design is available in all of the standard sizes, although it makes most sense to consider this design for the larger sizes (18-inches or larger).

The completed 22-inch

The dismantled telescope with the altitude bearings folded

For a review of this telescope, please see: http://www.cloudynights.com/item.php?item_id=1865
 

Specification of 22-inch f/3.6:

Total weight of this complete 22-inch f3.6 telescope:                 Approximately 45Kg  (of which 21Kg is the main mirror).

The dismantled lower assembly measures:                                Approximately 18" (460mm)H x 30" (760mm)L x 27½" (700mm)W

When used with a coma-corrector, such as the readily available TeleVue ParaCorr® this telescope gives very sharp wide angle views and  combines great portability with enormous light-gathering power and resolution. The positive location of the truss-tube ends means that collimation is automatically retained when the telescope is dismantled and re-assembled and the whole process of dismantling or re-assembling the telescope takes approximately 5 minutes and requires no tools.

For more detailed information or  to discuss any aspects of this telescope design, please ring me on 00 44 (0)115 9602266 or e-mail me at david_lukehurst@o2.co.uk.

For details of prices for the Ultra Portable and Standard telescopes, please see: Prices Page

Ultra-Portable Telescope Type 1/2

This is a picture of a 20-inch f/4 telescope which is a hybrid of the "Type 1" and "Type 2", with a "Type 2" lower assembly and "Type 1" upper assembly:

A Small "Type 2" Ultra-Portable Telescope

This design gives a very compact lower end when dismantled. The altitude bearing are removed and the mirror box stands in the rocker box. This 14-inch is then only 300mm high! This design is easier to make than the Type 1  and gives better shielding and protection for the mirrors. This design can easily be scaled to other sizes. In principle, the two designs (Types 1 & 2) could be combined with the lower end of the Type 2 fitted with the upper end of Type 1. Currently, I have made this design in sizes between 12" and 20". It is a very good choice where the most compact design is necessary for transportation.

Type 2 Compact 14-inch f/5 version

Dismantled mirror box/rocker box       Altitude bearings and truss-tubes 

Specification of Compact 14-inch f/5:

Weight = 31Kg (Tube assembly 23Kg, Rocker Box 8Kg)

Length = 550mm, Width = 500mm, Height = 300mm (The extreme dimensions of the dismantled mirror/rocker box assembly)

Length of Truss-tubes = 1270mm. Length of Altitude Bearings = 765mm

Height of eyepiece when telescope pointed at zenith = 1700mm

21st December 2016