Many amateur astronomers make sketches of what they observe at the eyepiece of the telescope. One of the challenges of this endeavor is that there is very little light to see by when observing with the telescope. Amateur astronomers use small red flashlights to see when observing. The red light has a minimal impact on the dark adaptation of the eye.
When making an astronomical sketch, you need one had to hold your clipboard, one hand to hold a pencil, on hand to hold the flashlight. A prehensile monkey tail or elephant trunk will work well if your are not a human. If this doesn’t work for you, then a method has to be devised to hold the flashlight. As a result, I began to experient with different solutions.
One solution is the backlit clipboard. This post will describe the details of the construction. Shown below is a photo of the clipboard:
This was a fun project in which the light source is placed behind the sketch. Using a backlit clipboard has a some advantages, listed below:
- no shadow of your hand and pen/pencil due to overhead illumination
- sketch is evenly illuminated across the entire page
- backlit clipboard can operate as a light box for viewing a page in reverse
Unfortunately there are also some disadvantages:
- light source is pointing at the user’s eyes
- clipboard is tall because the LEDs need space to project a beam of light
- clipboard is fragile, don’t drop!
- paper fibers are illuminated
- subtle shading is invisible
Next, the prototype unit described. I used it to create many sketches for a period of one year. The original clipboard was created from a red plastic storage clipboard. The hinge was removed with a Dremmel and 1″ aluminum flat stock was added to allow the LEDs to focus their light to evenly illuminate the surface. The inside was painted black with an 8.5″x11″ window to illuminate the paper. After this unit was dropped on asphalt during a 10 °F (-12°C) observing session and shattered, it was rebuilt into a Really Useful Box 8.5″x11″ paper storage box (not shown).
This version uses (65) 5mm Flat Top Red LEDs with a 555 Pusle Width Modulation (PWM) Circuit. Shown below is a photo of the inside of the clipboard, schematic and parts list. Each bank of LEDs can be switched on/off to minimize the amount of light pointing at the user’s eyes. The PWM circuit also is used to adjust brightness depending on conditions.
In conclusion, this is the prototype of the Backlit Illuminated Clipboard. I ended up trading the repaired prototype for a camera tripod. But I do have more materials to build additional clipboards/light boxes. So stay tuned for additional updates.
Do you have ideas for illuminated clipboards? Post your comments or send me an email!