The purpose of this project is to adapt & mount a …



The purpose of this project is to adapt & mount a green laser pointer to a telescope as an aiming device. The project is divided into 2 parts…

Part 1: Replacing the laser battery and on/off switch with external components. This is to prevent disturbing the target alignment of the laser & telescope when powering / de-powering the laser.

Part 2: Mounting & providing alignment housing for the laser to the telescope viewing axis.

Replacing the laser battery and on/off switch to external components

Parts:

• 5mw or greater Green Laser pointer powered by two AAA alkaline power cells.

• Plastic toilet water supply tube (pipe)

• Door hinge rod

• Large screw/bolt able to fasten/hold to inside diameter of plastic toilet water supply pipe.

• Large diameter soda straw

• Small diameter straw or plastic “coffee stirrer”

• Plastic electrical tape

• Optional Silicone Sealant

• 36 inch length of 18 to 24 gg 2-conductor flexible electric wire.

• “C” or “D” size battery holder for two 1 ½ cells (3vdc).

• Two Size “C” or “D” alkaline cells

• Small / Mini electric switch

• Small electronic “in-line” power jack & plug

• LED & 600 ohm resistor optional indicator lamp.

• Hobby box to encase battery holder, switch & optional indicator lamp.

Tools:

• Drill & small bit (1/8” to 1/16”)

• Metal file

• Hack saw

• Hobby wood or Coping Saw

• Soldering iron & solder

• Needle-nose pliers, wire-cutter / side-cutter, wire stripper.

Step 1: Creating the external switch & battery replacement.

A) Line up 2 AAA batteries end to end & place them against the plastic toilet water supply tube for measurement.

B) Mark the tube to a length approx 1/4 inch shorter than the 2 cells end to end.

C) Cut the plastic tube to length.

D) Cut the metal door hinge rod to approximately 2” length from the head.

E) Remove all burrs. Slide the hinge rod into the plastic water supply tube.

F) File the head of the hinge rod so the head is close to the external diameter of the tube.

G) Remove the hinge rod from the tube.

H) File one side of the rod to a flat surface making space for the 18~24gg wire between the hinge rod shaft and inside wall of the plastic tube.

I) Carefully drill a 1/8” hole in the center of the hinge rod head through to a depth that enters the hinge rod shaft.

J) From the flat side of the hinge rod shaft (step 1H), drill a 1/8” hole that meets the previous hole drilled in step1I.

K) File / sand the metal edges smooth so they don’t cut or snag the wire insulation.

L) Draw the 2-conductor wire through the holes drilled in the hinge rod.

M) Cut one conductor of the wire about 2 inches shorter than the other. Strip the shorter conductor’s insulation bare to wrap around the hinge rod.

N) Insert both wires and rod back into the plastic tube. The longer conductor should be extending beyond the open end of the tube. Mark (identify) which conductor is wrapped around the rod & which extends out from the tube for electrical polarity later.

O) File the end of the screw/bolt so the head is about equal to the diameter of the plastic tube. If the screw has a very round head you may want to somewhat flatten the top of the head.

P) Strip the insulated end of the longer conductor. Place the bare wire at the end of the tube & screw in the large screw/bolt into the end of the plastic tube with the bare wire contacting the screw.

Q) Add a daub of silicone caulk to the head of the hinge rod. Cut a small piece from the coffee stirrer straw, thread the wire and slide to insert it in the hole of the hinge rod.

R) Remove the end cap & batteries from the laser.

S) Drill a hole in the end cap and thread the wires through the cap. Insert the “Dummy” batteries into the laser.

T) Solder the power PLUG to the wire. Insure the center post of the plug connecting to the hinge rod is “plus” positive polarity.

U) Lastly, cut the large soda straw length-wise and place & press over the on/off push-button so as to hold it in the “on” position. Use the plastic electrical tape to hold it in place keeping the laser “on”.

V) At the hobby box, solder the battery case to the remaining switch and in-line power socket. Arrange as desired. Insure the center post polarity is positive.

Mounting & providing alignment of the laser to the telescope axis.

Step 2: Creating the alignment housing.

Parts:

• Plastic wire spool or equivalent cylinder with inside diameter approx 1.5x wider than laser pointer width. Ex; PVC Pipe.

• 4 Small & long screws (If screws are pointed, file ends flat)

• “Crazy Glue” or equivalent

• 1 x 1 x 6” Closed cell packing foam or door threshold weather-seal foam tape

• Small hard objects (Cable tie, BB, small nut, etc…)

Tools:

• 2 to 4 Large rubber bands

• Small screw driver

• Needle-nose pliers

The object is to mount a hollow tube to the scope body that will allow the laser pointer to “float” within the housing.

A) If using cable spool or other such part for housing, cut flanges to fit telescope tube. Drill 4 holes to accommodate adjustment screws.

B) Place hard object at center of laser pointer body to provide pivot point (fulcrum).

C) Wrap the laser pointer in foam to provide flexible spring-back action.

D) Squeeze / slide assembly into mounting tube (cable spool). Trim excess foam off ends. Insert adjustment screws in holes.

E) Using rubber bands, mount the assembly to telescope body as parallel to viewing axis as possible. Fasten with “Crazy Glue” when satisfied with general alignment. Allow dry time then remove rubber bands.

F) Mount the scope & focus on target at least 700 ~ 1,000 feet away (Ex; tree). Make fine alignment adjustments using the adjusting screws. Be sure to loosen one screw before tightening its opposite. Using the scope at that distance, you should be able to see & center the green dot clearly with minimal parallax. Looking through the eyepiece at the night sky with the laser on, a green haze will appear as if a comet tail. Insure the laser is “off” during viewing.

Final note. Painting the rear flange of a wire spool white & drilling a small hole through the front flange makes a simple solar targeting site. The small hole will cast a bright spot on the rear flange that can be marked for target alignment.

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