Sunday, August 31, 2025

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.


Want additional astronomy-themed articles? Click for "astro topic" search results in my blog.

Thursday, August 7, 2025

Planisphere, Star Atlas, Stellarium, Oh, My Stars!

Starting out viewing the night sky? This article briefly describes three items recommended for beginner astronomers (recent astronomy club presentation Navigating the Night Sky). Resources for more info follow.

  • Planisphere—a handheld flat, circular item for identifying stars and constellations that are visible in the night sky for specific time and date
  • Star atlas (aka sky atlas)—a map of the night sky, to locate and identify celestial objects. Can be in book or chart form that maps the positions of stars, constellations, and other celestial objects in the night sky.
  • Stellarium—free open-source planetarium software that provides 3D simulation of the night sky

Planisphere, Star/Sky Atlas

This section covers both planispheres and star/sky atlas' because of interrelatedness in Google results.

YouTube video— "How to use a Planisphere" (9:09), latitude version shown—40° to 50°

From video description:

Step by step instructions on using a planisphere for locating objects in the night sky. This is a useful tool in astronomy for locating constellations and other notable features.

Where to buy? Amazon browsing for "planisphere" shows various planispheres and some sky atlas'.

Noteworthy—above webpage includes a link to "Starfinder: The Complete Beginner's Guide to Exploring the Night Sky Hardcover – October 21, 2013" ($25),

Now with removable planisphere!

Where to buy star atlas or sky atlas?
Amazon results for "star atlas"
Amazon results for "sky atlas" (more varieties of offerings)

Prices: From under $10 to astronomical

Stellarium

Stellarium is free software for Windows, Mac, or Linux. Download from main page https://stellarium.org

Stellarium is a free open source planetarium for your computer. It shows a realistic sky in 3D, just like what you see with the naked eye, binoculars or a telescope.

Note the system requirements to ensure if you can install on your device.

Read features section to discover sky items to see, when you can see them, and various other info. (Before you look for sky objects, you must set the tool for where you are and the date/time.)

Additional Resources

Visit Cloudy Nights Forum, "Beginner Star Gazing: Planisphere, Star Atlas, or Sky Maps?" for comment and recommendations.

"Want to learn how to stargaze? Here's how to get started in 12 easy steps" provides helpful titled subtopic sections, such as
  • Read beginners' books and online resources
  • Choose your stargazing site
  • Let your eyes adapt to darkness
  • Take time to observe individual stars
  • Spot the planets with your naked eye
  • See how the stars move across the sky
  • Get kids and family involved
  • Learn the constellations and asterisms (informal but recognizable star patterns, which can be part of one or more constellations)

Related: "Constellations and asterisms: what's the difference?"

"How to Stargaze" includes handy titled sections as follows:

Stargazing for Beginners
 Start by Looking Up
 Locate the Big Dipper
  Locate Other Bright Star Patterns
Helpful Stargazing Tools
 Star Charts or Stargazing Apps
 Grab Binoculars
 Borrow a Telescope

Note: If you join Austin Astronomical Society (AAS), you can borrow a telescope. (Membership levels are at "To Join AAS".)

From "Become A Member"

Loaner Scope Program

8″ Dobsonian telescopes with very good eyepieces and all the needed accessories to have a good visual observing experience or to test your next scope upgrade!

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