14" f/5,1 Phoenix and  his 4" Reiterlein

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Primary Mirror (self made): 
Material: PYREX 7740
Diameter: 14" (350mm)
Thickness at the edge: 1,36" (35mm)
Focal length: 70,5" (1790mm= f/5,11

Secondary mirror:

2,6" minor axis, 94% reflection

Total weight:
Telescope: 52,6 lb without eyepiece, without finder scope

4,2" (106mm) Newtonian, 17,2” focal length = f/4,1; Rigel Quickfinder at the secondary cage


Secondary holder:  Excentric vane made of  1mm (0,04”) steel sheet, in the middle a 1,2” piece of a square-pipe tube with threated hole , 3mm(0,12”) offset included. The 66mm (2,6”)  diagonal is silicone glued with 3 blobs of 2 mm (1/10") thickness directly onto to the diagonal al-sheet.  The sheet  is 3mm (0,12”) thick and was bended by hand in a bench vice. The holder can be collimated with 3 pcs. M4 (0.16")  butterfly nuts. It works wonderful.

Secondary cage:  Two rings of 0,7“ thick and 1” wide rings made of Baltic Birch plywood, connected by 10 mm (0,4“) aluminium square-pipe tube. The cage is covered with 1mm (0,04”) airplane plywood, this increases the stiffness dramatically. Focuser: KineOptics Helical HC2. The upper pole seats was drilled and sawn out of multi-layer wood plane, clamping with quick release skewers.

Trusses: 20mm (0,8“) aluminium pipes, tickness 1mm (0,04“) Wandstδrke 1mm, covererd with shrunk-on hose.

Azimuth bearing: 3 small side pivot the rocker onto the ground, Bearing on Baltic birch multiplex triangle wit Teflon. Ebony star formica on the bottom side of the rocker, to rub with car-polishing liquid makes moving much smoother.

Primary Mirror Cell: A 18- point flotation cell with a sling like described in David Kriege's book, but mounted on wooden board. Threated inlays made of cutted brass dowels. The geometry of the cell was optimized with the program PLOPP from David Lewis.

Cooling: 8cm (3,2“) PC-fan from down central, 4cm (1,6“) CPU-fan from the front, both switchable, the  CPU-fan is adjustable.

Altitude Bearings: lightweight and stable, looking really pretty. 500mm (20“) diameter. Made of 21mm (0,8“) thick baltic birch plywood as to be seen at Stathis Kyklopas , planked with 1mm (0,04”) aluminium. The bearings can be removed, but with a 14” truss Dobson this is normally not necessary.

The rocker:: more massive as really necessary. The ground board is made of 21mm (0,8“), left and right side  of 24mm (1“), front and rear of 18mm (0,7“) baltic birch plywood. All made by a cheap (60 Euro) mechanical fret saw. This needs a lot of endurance.

The finder:  the “look” is adjusted to the main telescope. Trusses made of 8mm (0,3“) aluminium pipes. 106mm (4,2”) free diameter, 17,2” focal length. With a 25mm (1”) eyepiece a 3 degree effective field of view can be overseen. The Mirror is self made, the mirror blank was a gift of Raphael Bugiel at the ITV (look ITV Spiegleschleifworkshop).

Lower Split Block Sockets: 35mm (1,2“) baltic birch plywood, Clamping with quick release skewers

Finder Mounting: Collimation is done within seconds via a center pull bolt and 3 push bolts. Many thanks to Stathis Kafalis for this great idea!

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