Laptop Screen Too Bright During Night Sky Session?

If you do night sky observing or astrophotography, you learn that your eyes adapt to the night sky, but bright lights quickly thwart the vision. Using red lighting is suitable for seeing objects and retaining the night vision. Use a clear plexiglass sheet over a laptop screen to achieve a night-sky user friendly interface.

If using a laptop during a session at night, some software tools have night settings—changing white background to dark, and text to red. The user can vision-adapt to the night sky or continue to not have night vision disturbed. Other nearby astronomers can also be retain their night vision.

Our rather old and lower-end laptop has limited capabilities for night sky adaptations. The keys don't have red displays. The astronomy software tools are not commercially developed specialized packages, but open-source tweak-it-yourself tools.

Our Laptop Screen Fix—Red Overlaying

We picked the clear red plexiglass (details farther down, more elaboration in the YouTube video). The minimal fix would have been to order the best-dimensions pre-cut sheet and simply lay it over the screen.

With an eye for frugality, we trimmed excess height, saving a piece for possible future project(s). With consideration for secure fastening, then drilled small holes for shoelacing the larger piece to the laptop screen. View the video for guidelines on our overlay fix for the laptop screen.

Laptop Screen Overlay Candidates

Online, we researched getting a clear red overlay for placing in front of the laptop screen during astrophotography. Ideas for See-through red screening included the following:

• Red cellophane that florists use
• Acrylic sheets from Michael's and Hobby Lobby
• Acetate (polypropylene) sheets at Michael's
• Rubylith (photographic plastic)
• Red tail-light tape
• Clear red plexiglass

After consideration, most of the items have downsides, which I cover farther down the article. First, the winner!

Clear Red Plexiglass

The fix we chose was a clear red plexiglass from Canal Plastics Center in NY—"Red Transparent Acrylic Sheet" ($3.68 for 6" x 12" x 1/8" initial offering)

Also known as plexiglass, lucite, or perspex, acrylic is a popular and versatile plastic for many applications. It is a common substitute for glass as it is crystal clear, lighter, more shatter resistant and easy to work with. Acrylic sheets can be laser cut or saw cut, as well as machined with routers, drills and sanders.

The webpage provides good pricing info for the multiple precut dimensions and thicknesses. (We picked 12 x 18 for laptop fit.) Other interactive webpage options included custom dimensions, holes, edge finishings, and shipping priorities.

A Close Candidate Red Plastic, But No Cigar

"Lesnlok Red Acrylic Sheets - 1/8" Thick, ..."

Translucent red plexiglass red acrylic,with 2 pieces of red acrylic sheet,This acrylic resin has excellent optical stability and uniform thickness.

The term translucent nudged us away, along with two negative reviews that indicated shortcomings of using the product.

The No-go Reds

The other red transparent items under consideration were food for thought, but didn't seem suitable enough.

 Red Cellophane Wrap, Used By Florists

It took some doing to find out what the item was called. Wound up with reasonable finds when googling "Cellophane wrapping paper for floral arrangements" and "floral arrangement red transparent wrapping mylar sheets". AI showed reasonable info for the product—"red transparent wrapping mylar sheets, often called red cellophane wrap"

An Amazon find further helped with info—"Vanhench Red Cellophane Wrapping Paper, ...". Color and transparency were winning points, however, the product looked too flimsy and scrunchy.

 Acrylic Sheets from Michael's and Hobby Lobby, Acetate (polypropylene) Sheets at Michael's

These products are bundled with additional color sheets and tend to be smaller than laptop screen sizes. It didn't look feasible to buy package deals to obtain a onesie-twosie (red) item.

 Rubylith, Used in Photography Masking

In the distant past, I used rubylith for printed circuit board artwork layout, particularly analog circuitry. Technology has long made manual layout obsolete; however, photographers and artists still buy the product.

Snippet description from "Rubylith"

Rubylith consists of two films sandwiched together. The bottom layer is a clear polyester backing sheet; the top layer is a translucent, red (ruby) coloured sheet. The top layer can be cut and peeled away from the bottom layer.

Idea discarded—

• Color translucency reduces clarity and readability of screen info.
• Colored sheet could be easily damaged, letting light bleed through and reducing effectiveness for user.

 Red taillight Lens Repair Tape

The tape comes in about 2" width rolls. We considered taping a small piece onto a scrap piece of 7 mil clear mylar to test transparency. Even if the small sample looked OK, idea of pulling and taping SEVERAL aligned rows was not appealing. Also, transparency might less than optimal because of tape's intended use on taillights.

Advisory Webpages for Buying, Cutting, and Drilling Plexiglass

1. Canal Plastic Center "Red Transparent Acrylic Sheet" (pre-cut 12" x 18" x 1/8" sheet)
2. "Cut Plexiglass, Acrylic, Plastics with Draw Knife Scoring - Cheap, Fast", 1:49
   My gist: Draw knife, thin plexiglass, main points-draw knife several times on firmly held-down plexiglass (using metal straight edge), then snap.
3. "How to easily drill plexiglass, lexan and acrylic sheets", 3:10
   My gist: Clamp plexiglass to scrap board, then use step drill or twist drill with tape protection and lubricant. Additional drilling considerations--slowness, light pressure.
4. "Simple Solutions: Tips for Drilling Through Plexiglass", 0:44
   My gist: Sandwich plexiglass between two layers of quarter-inch plywood ... mark the holes ... line plexiglass with plywood ... drill right through all three layers.

Related: Keyed-in text and image of PLASKOLITE Plastic Cutter for cutting plexiglass.

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DIY Red-light Head Light

You might ask, "Who would want a red-light head light?" Well, amateur astronomers, for hands-free seeing at night, especially if they're carrying or handling equipment, such as telescopes. Other night-sky observers might want to wear them for being able to walk around without bumping into people or items, and they can retain night vision while viewing objects, whether through telescopes or binoculars at night-sky watching events.

You might wonder why it's important to use red light at night to see with instead of using other-color light. Red light helps illuminate dark areas without adversely affecting night vision. Eyes need time to adjust to dark surroundings. At night, when someone turns on a non-red light, such as car headlights or white-light flashlight, sky objects become less visible and vibrant until the eyesight becomes re-accustomed to darkness.

A red light head light is a modification of an off-the-shelf elastic headband lamp. (More on acquiring the lamp and similar later.) The bulb itself is white—suitable for normal uses. For astronomy purposes, the light needs to be red.

Step-by-step Modifying Regular Headlight to Red Headlight

The video shows items needed, procedure, and white lightcircle next to red light circle. Items required:

• Head lamp (Western Safety brand) or similar elastic-band lamp with center bulb
• Red automotive tail light tape, available at auto parts stores
• Scissors

Note: The tape should be wider than the diameter of the lamp's screw-on transparent cap. For example, the tape I used was 1 7/8" wide, and the cap was 1 5/8" across. (Ruler in video is for tape width reference.)

Procedure

1. Unscrew the retainer ring with clear cap from the rest of the lamp.
2. Separate the clear cap from the ring.
3. Cut a squarish piece of red tape that overlaps the cap with a reasonable margin all around. In my case, the tape was wider than the cap diameter by only 1/4".
4. Firmly place the center of the flat part of the cap onto the sticky part of the tape.
5. With scissors, snip the red tape's corners and sides up to the cap's edge.
6. Fold and evenly press each of the snipped tape corners to the cap's edge, pressing at opposite corners for evenness in stickiness and surfaces.
7. Press the retainer ring back onto the cap.
8. Screw the retainer ring and cap onto the lamp.

For contrast, the video shows red and white flashlight circles side by side.

Getting an Elastic-band Headlight

Western Safety manufactures a headlamp commonly available at Amazon and Harbor Freight. Amazon's price is $1.79, and Harbor Freight's list price is $2.99. For additional types of headlamps, visit Google image offerings.

Some Caveats of the Western Safety Headlamp

You might run into at least one of the following situations if you get headlamps that this company manufactures. The first two items have workarounds.

• Slots for straps might be wide; straps might loosen from the unit. (Tape the strap pegs together.)
  
  
  
  Related: Contrast two styles of strap retainers and slots.
  
  
  
  
• Straps might be short (tight fit) for the wearer. (Stitch an extender, such as a piece of a lanyard or wide ribbon.)
  
  
  
  
• Switch sometimes doesn't turn on reliably.
• Battery cavity can be slightly undersized and batteries not fitting well.

Want additional astronomy-themed articles? Click for "astro topic" search results in my blog. Related: Sky/Astronomy Items YouTube playlist