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Telescope Assembly Instructions

Instructions for Assembling Dobsonian Telescopes Kits

Kit Contents Tube Aluminum Secondary Spider 11/4" Focuser Swivel Box Mount Assembled Aluminum or Wood Primary Mirror Mount 12 6g x 25mm wood screws 5 8g x 20mm wood screws 4 8g x 20mm  bolts and nuts 3 8g x 10mm bolts and nuts 9 3/16" washers 8 spacers for mirrors 2 thrust washers Base Spigot 4 rubbing strips 2 Swivel Box Spigots Circular Base with Feet and Anti Friction Pads Base with Formica Bearing Surface 2 Sides left and Right Front Rear Primary Mirror Secondary Mirror 8x50 Finder 10 and 20mm Plossl Eyepieces 2x Shorty Barlow Lens 9" Sonotube Collimating Eyepiece 1 Medium Nylon Scope Cover 2 Velcro Straps 2 Cans Gloss Black Spray Paint Enamel 1 Can Flat Black Spray Paint 1 Bottle PVA Glue

Tools and Accessories Phillips head screw driver Flat head screwdriver Clear silicon sealant Black marker Picture - Ron Royle, "Build Your Own Telescope". Sydney

Assembly Instructions

1. Screw and glue together the sides of the Dobsonian mount
2. Screw and glue together the assembled sides in 1. and the circular base
3. Spray paint the assembled Dob mount, base and swivel box gloss black
4. Spray Paint the inside of the tube flat black
5. Spray paint the outside of the tube with enamel
6. Attach the swivel box mount and base spigots in the holes provided.  Place the thrust washes around the base spigot so the  telescope does not rest entirely on the Teflon pads.   Glue the Velcro rubbing strips on the sides of the swivel box.

7. Screw the Secondary Spider to the tube so it is centered under the focuser hole
8. Screw the focuser into the center of the focuser hole
9. Attach or glue the Secondary Mirror onto the secondary holder with clear silicon and spacers
10. Adjust the spider so the secondary mirror is centered under the focuser.  Use the collimating eyepiece to center it properly.
11.  Measure the height of your focuser in its midway position above the tube and add half the tube diameter to determine the distance above the secondary mirror.
12. Subtract this distance from your primary mirrors focal length to determine the distance from the primary mirror to the secondary.
13. Attach or glue the primary mirror to the primary cell using silicon and spacers.  Be sure the primary is centered in the cell.
14. Put a dot in the center of the primary with a black marker pen
15. Measure the distance from the face of the primary to the screw holes on the primary cell.  Add this distance to the distance calculated in 5.  This is the distance your primary mirror cell will be from the center of the focuser hole.
16.  Measure the distance to the primary cell from the focuser and mark the screw holes
17. Attach the primary cell and mirror to the tube
18.  Test the scope by pointing at the Moon and focusing to determine whether the primary is correctly positioned.  The image will not be centered as the scope is not yet collimated.  The image should come into focus when the focuser is at its midway position.  You will have to move the position of the primary closer or further to the focuser if you cannot focus the image correctly.
19. Adjust the primary mirror with the collimating screws on the primary cell until the reflection of the front tube hole in the focuser is centered.  Use the collimating eyepiece to fine collimate the scope by adjusting the secondary spider as described in the collimation instructions.
20. Attach the 8x50 finder scope

1. Distance between center of focuser and primary mirror face for 8" f/6 Newt with 9" OD Tube and 11/4" Rack and Pinion Focuser - 41"
2 Add the distance from the primary mirror face to the mirror holder mounts - 2"
3. Total distance from center of focuser to primary mirror cell for 8" Newt with 11/4" Rack and Pinion Focuser - 43"

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Text Copyright © 2004-2010 by Rob Kanen