Red Tripod Light for Astronomy

When using a telescope in the dark, you need to maintain the night vision required for the best seeing, but you also may need to have light to see star charts, find eyepieces, or many other things. The red spectrum of light maintains the night vision better than other colors and many people just use a flashlight with a red filter. I decided I wanted a more permanent and a less-likely-to-lose light that would also keep both hands free for other tasks.

My solution was to design and build a red LED light attached to the bottom of the tripod head that cast a dim red light onto the tray of the stand.

Materials

35mm canister

3/4” PVC coupling

1/2” PVC pipe

4 batteries (CR2032)

Sheet metal

Wire

4 red LEDs

Breadboard

Solder

100 ohm Resistor

Double stick tape

Switch

Solder

Duct tape

Electrical tape

Black foam core

Tools:

Soldering iron

Wire cutters

Utility Knife

Hot Glue Gun

Now it’s time to build the LED array on the breadboard. The
first step is to drill a ¼” hole in the center. This will be the attachment point to the tripod head.

Insert one LED into the corner of the breadboard and bend legs from backside of board. Now solder each leg onto the board. Repeat with the remaining three LEDs. Connect negative leg (shorter of the two) of LED one to the positive leg of LED two. Repeat this connecting LED 2 to 3, and 3 to 4.

Insert resistor through bread board and attach one end to negative terminal of LED 4. And other end to breadboard where the negative wire will attach. Solder positive terminal from LED 1 to breadboard where positive wire will attach and solder both wires to board to complete circuit.

Trim ¾” coupling to 1¼” length.

Cut 2 rings from the ½” pipe- one ½” long the other ¼”

Cut a 2 ¼”” strip from sheet metal 3/8” wide . Cut in 7/8” off and then trim to fit snugly in the coupling.You will need to trim the edges to a round profile to fit within the coupling, but do not cut too small, it should fit snugly but not tight.

The remaining piece of metal should be bent to make a 1/8” rise as shown in picture. This will the need trimmed as before to fit snugly in the coupling

Drill a 3/32” hole in one end of each strip for to insert wire.

Cut 8” length of wire and strip each end solder one end of wire to a metal strip. Repeat the other wire and metal strip. The black wire should connect to the metal with the 1/8” bend, the red to the flat strip.

Cut slot for switch into side of film canister near bottom and a smaller slot near cap for wires. Insert switch into canister and position into slot at bottom. Use hot glue gun to affix switch to canister.

Insert batteries into coupling with the negative side down, and then insert the flat strip through the center of the ½” thick ring. Insert ring into coupling to hold the strip against the batteries. Insert the other wire through the ¼” ring and insert into other end of coupling. Cut the red wire 2” from the coupling and solder the red wire from the battery to the switch.

Then solder one end of the remaining red wire to the other contact on the switch. The insert PVC battery holder into canister and feed wire through hole near top. Put cap onto canister to complete the power cell

Cover entire back of circuit board with duct tape.

Cut black foam core to size to cover the entire circuit board. Mark and punch holes in the location of each LED. Then attach the foam core with electrical tape to secure to circuit board. This mask will shield and excess light from bleeding to the sides and keep any follow astronomers near from any light shining their direction. Remember to cut a hole in the foam core to match the attachment hole drilled into the circuit board.

Attach circuit board to bottom of tripod head. There should be a bolt at bottom of tripod head, remove this bolt and attach circuit board to tripod, then reinsert bolt and tighten. Use double stick tape to attach canister to bottom of tripod head.

This lighting system has made it just a little easier to use my telescope in the dark of night without needing to hold a flashlight when I need to read the charts.