DAVID LUKEHURST

ASTRONOMICAL TELESCOPE MAKER

Astronomical Telescopes for the Discerning Observer

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

It is currently my intention to make the Ultra-portable telescopes with the "Type II" lower end. The upper assembly can be either as in the "Type I" seen below, or as in the standard telescopes and as seen in the "Type II" design below

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

 Ultra-Portable Telescope Type I

I have recently constructed the first example of the Ultra-Portable versions of my telescopes.

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 II

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 I  and gives better shielding and protection for the mirrors. This design can easily be scaled to other sizes. In principle, the two designs (Types I & II) could be combined with the lower end of the type II fitted with the upper end of type I.

Type II 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

Ultra-Portable Telescope Type I/II

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

22nd June 2010