Description

This is a merge of the two previous Stars Trackers I made. I wanted a model that could be both manual and motorized. This thing is "really" a work in progress since I have not taken any picture with it yet. In the next few days the moon will rise late so I'll give it a shot at the first clear sky.

This type of astrophotography mount is often called a barndoor mount, a scotch mount or a Haig mount. This mount allows you to take long exposure of the night sky by canceling out the apparent motion of the stars in the sky. 

You can get more information on this type of device on Wikipedia:
en.wikipedia.org/wiki/Barn_door_tracker.

The NEMA17 motor is driven by an Arduino arduino.cc and the Adafruit Motorshield adafruit.com. I am still working on the Arduino software. The objective is to compensate for the error induced by the linear motion trying to emulate a constant speed rotation.

I made a short video to demonstrate hot to change from the motorized version to the manual version of the Stars Tracker. 
youtube.com/watch?v=pLnhl2p-kOQ&feature=feedu

The drawings have been made using Sketchup. The original drawings can be found in the starstrackerv2.0.zip file.
Instructions

Print and assemble ... the important dimension is the distance between the center of the hinge and the pivots, which is 145mm.

The non-printed parts you will need:

Main assembly:
--------------
2x 3/8" threaded rod 6.25" long
8x 3/8" nuts
1x 3/8" bolt 3/4" long (camera head)
4x 608 bearings
1x M6x35 8mm shoulder bolt
3x M8 washers
1x M6 nut
1x 1/4" nut (tripod attachment)
1x 10mm diameter tube for polar alignment

Motor assembly:
---------------
4x M3x12 bolts
2x M3x8 bolts (coupling)
2x M3 nuts (coupling)
1x NEMA17 stepper motor
1x 1/4" 20TPI threaded rod 6" long
1x 10mm diameter and 20mm long cross-dowel with a threaded hole

Manual assembly:
----------------
5x 1/4" nuts
1x 1/4" butterfly nut
2x 3/16" #12 washers
1x 1/4" 20TPI threaded rod 6" long
1x 10mm diameter and 20mm long cross-dowel with a threaded hole

Electronic:
-----------
1x Arduino arduino.cc
1x Adafruit Motorshield adafruit.com/products/81