INSTRUCTION MANUAL DOBSONIANS 150mm/1200mm 200mm/1200mm 254mm/1200mm
TABLE OF CONTENTS Assembling Your Telescope 3 Parts List Base Assembly Optical Tube Assembly 3 4 5 Operating Your Telescope Aligning the Finderscope Focusing Using the optional Barlow Lens Using the Tension Control Handle Pointing the Dobsonian Calculating the Magnification (power) Calculating the Field of View Calculating the Exit Pupil Observing the Sky Sky Conditions Selecting an Observing Site Choosing the Best Time to Observe Cooling the Telescope Adopting Your Eyes Proper Care for Your Telescop
BASE ASSEMBLY 1. Connect the board B to the board A1 and A2. Make sure the logos on the board A1 and A2 are on the outside. The side of the board B with three small holes should be facing the front. 2. Connect the assembly to the round board C. 3. Attach the round plastic feet to board D. Place the teflon pad in between the assembly from step 2 and the board D. Insert the black tube from package 2 through the holes in the centre of all the above.
OPTICAL TUBE ASSEMBLY 9. Place the optical tube between the board A1 and A2. Make sure that the side bearings of the tube are rested on the 4 cylindrical saddle side bearings. 10. Install the handles from package 7 into the holes on the board A1 and A2. Do not over tighten the handles. Make sure that the tension control handle is installed on the same side as the focuser for your convenience. 12. Slide the finderscope bracket 11. Locate the finderscope bracket 13.
OPERATING YOUR TELESCOPE Aligning the Finderscope Fig.a Fig.b These fixed magnification scopes mounted on the optical tube are very useful accessories. When they are correctly aligned with the telescope, objects can be quickly located and brought to the centre of the field. Alignment is best done outdoors in day light when it's easier to locate objects. If it is necessary to refocus your finderscope, sight on an object that is at least 500 yards (metres) away.
Using the Tension Control Handle Fig.e tension control Loosen or tightend the tension control handle to add just enough friction to allow the tube to move easily when nudged but to stay in position when not. It may be necessary to re-adjust the tension control handle when accessories are added to, or removed from, the tube. The tension control handle should be installed on the same side as the eyepiece for your convenience.
Calculating the Magnification (Power) The magnification produced by a telescope is determined by the focal length of the eyepiece that is used with it. To determine a magnification for your telescope, divide its focal length by the focal length of the eyepieces you are going to use. For example, a 10mm focal length eyepiece will give 80X magnification with an 800mm focal length telescope.
Sky conditions OBSERVING THE SKY Sky conditions are usually defined by two atmospheric characteristics, seeing, or the steadiness of the air, and transparency, light scattering due to the amount of water vapour and particulate material in the air. When you observe the Moon and the planets, and they appear as though water is running over them, you probably have bad "seeing" because you are observing through turbulent air.
PROPER CARE FOR YOUR TELESCOPE Collimation Fig.g Collimation is the process of aligning the mirrors of your telescope so that they work in concert with each other to deliver properly focused light to your eyepiece. By observing out-of-focus star images, you can test whether your telescope's optics are aligned. Place a star in the centre of the field of view and move the focuser so that the image is slightly out of focus.
Aligning the Primary Mirror hex bolt inside There are 3 hex bolts and 3 Phillip's head screws at the back of your telescope, for 150mm/1200mm and 200mm/1200mm the hex bolts are the locking screws and the Phillip's-head screws are the adjusting screws. For 254mm/1200 the flat headed screws are the adjusting screws and the thumbscrews are the locking screws (Fig.l). Use an Allen wrench to loosen the hex bolts by a few turns.
Caution! NEVER USE YOUR TELESCOPE TO LOOK DIRECTLY AT THE SUN. PERMANENT EYE DAMAGE WILL RESULT. USE A PROPER SOLAR FILTER FOR VIEWING THE SUN. WHEN OBSERVING THE SUN, PLACE A DUST CAP OVER YOUR FINDERSCOPE TO PROTECT IT FROM EXPOSURE. NEVER USE AN EYEPIECE-TYPE SOLAR FILTER AND NEVER USE YOUR TELESCOPE TO PROJECT SUNLIGHT ONTO ANOTHER SURFACE, THE INTERNAL HEAT BUILD-UP WILL DAMAGE THE TELESCOPE OPTICAL ELEMENTS.
