Creating Sky Maps for Laser Etching

Born under Scorpio skies? Using sky maps, we are able to visualize what the sky looked like at the exact moment you were born, or some other significant occasion like a wedding. These sky maps are beautiful, and make for perfect vector images for laser etching. There are already great, free software and online tools available to generate and edit the sky maps to your liking.

I am making a gift for the best water sign in my life, a Pisces. They were born in March, predominantly under the star Matar in the Pegasus constellation. This star is the right knee of the Pegasus flying horse, and supposedly give a person enthusiasm and ambition. I want to create a sky map for them, laser cut on birch plywood, highlighting the constellations (especially Pegasus).

In this Instructable, I will show you how to use the available tools to use web services to generate a sky map and basic image editing to prepare the image for laser etching and cutting. This should be good practice for someone looking to learn how to create files for laser etchers and cutters. The focus of the Instructable is not how to operate your laser cutter.

• In-The-Sky.org website
  • generates the skymap according to the time, date, location
• Inkscale vector graphics software, and basic understanding of use
  • You could use some other vector graphics software of your choice if you are more familiar
• Etching material of your choice
  • I used 1/4in birch plywood
  • If you don't have a laser cutter, you could instead send the SVG file you create here to an on-demand print service like Sculpteo or Ponoko

1. Open In-The-Sky.org sky map generator

   • https://in-the-sky.org/skymap.php

2. Click the Change Time button and enter the exact date and time of the event. The hour and minute are required.
   1. Under this section, you can also select the Limiting Brightness, which will display more or less stars.
3. Click the Change Location button and enter the location of the event.
4. Choose the Printer Greyscale color scheme from the drop-down box.
   1. You may further edit the color scheme using custom fields. Because we are opening this file in Inkscape next, this is not necessary.
5. Select the specific options you would like the display on the sky map.
6. When satisfied with how the sky map is looking, being conscious of how the image will be reflected as an etching, click the Export SVG button.

Depending on how you customized your file. you will need to do at least some editing before we have a file that is ready for laser cutting. Let's open the file in Inkscape to remove vectors that we don't want in the finished product.

Now that we have the sky map, let's clean it up and prepare it for our laser cutter. Many laser cutters interpret vector image files, like SVG, as black text or art as "raster" - an etch into the material. Red will be a marker for where I'd like the laser cutter to cut through the material.

As you see, the vector image we pulled in straight from the generator has some elements that won't laser cut well, and the color is all off. I ended up deleting several elements and creating a thick band to smooth the jaggedy edges of the galaxy shading. Finally, I created a red ring with a slightly larger diameter to mark where I'd like the design to be cut out.

The vector may have multiple elements grouped together, grouped multiple times even. Usually, by carefully ungrouping and checking to see if the problematic element is broken free from the rest of the image, you can preserve what you would like to keep and manipulate only what you need.

First and foremost, of course, follow all necessary safety precautions. Wear your eye protection with proper wavelength protection. Never open the lid while your laser is running.

In your laser cutting software, load the file. Because we edited the file to only contain red and black colored elements, the laser cutter can understand what to do. The laser will be powered on following along all black colored lines, text, and art - running at the raster engrave speed. Where it is red, the laser will run at a slower speed and subsequently a higher laser power.

I used a K40 laser cutter with air assist and the K40 Whisperer controller. The SVG generated should work just fine for more reputable laser cutters or smaller diode-based laser etcher/cutters. This Instructable is not intended to serve as guidance for how to laser cut the file.

If you are looking into getting into laser cutting, you will likely find that a K40 will be your most affordable option. I would highly recommend against purchasing a K40 laser. If you are using a K40, please follow the safety guide in the Resources page. Please use a laser cutter from a company with better safety and features, like the Glowforge laser cutter. I hope to upgrade my setup to something a bit better someday.

Overall, I am very happy with this piece. With some light touching up, a couple coats of stain and finish, it will be a beautiful gift for the Pisces in my life.

Thanks for checking out this Instructable, my first one.

• In-The-Sky Sky Map generator by Dominic Ford

  • https://in-the-sky.org/index.php

• Inkscape

  • https://inkscape.org/

• Glowforge laser cutter

  • https://glowforge.com/

• Scupteo on-demand print service

  • https://www.sculpteo.com/

• Ponoko on-demand print service

  • https://www.ponoko.com/

• K40 Whisperer

  • https://www.scorchworks.com/K40whisperer/k40whispe...

• K40 safety guide

  • https://www.wargaming3d.com/2019/09/06/chinese-k40...