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MicroObservatory's Lunar Eclipse Challenge

On January 21st, 2019, the Western Hemisphere observed a total lunar eclipse.

Now you can recreate this eclipse, using MicroObservatory telescope images. First we’ll take you through the steps of using our JS9-4L image processing tool.

If you're familiar with animating images in JS9-4L, you can click the × in the upper right corner. You can always come back to this tour by clicking "Replay Guided Tour".

Start Guided Tour

Select an Image

First, click on one of the image files of the moon. It will open inside the JS9-4L frame.

After you've finished the guided tour, all of the images that you need for this challenge are available here, under the Lunar Eclipse tab.


Adjust the Scale

Use these scales to highlight different regions of relative brightness in your image. Log scale works best for dim images.

Switch between the scales to see how regions that appear black suddenly reveal much greater detail.


Adjust the Brightness Limits

Hover over the darkest parts of your image. Watch the green number inside the parenthesis next to "Pixel Value" above. Type the lowest value you see into the Low Brightness Limit box.

Now hover over the brightest pixels of the moon. Watch the green number inside the parenthesis next to "Pixel Value" above. Type the highest value you see into the High Brightness Limit box.


Special Tools for Animating Images

In order to line up all of your moon images and animate through them, you will need to use the Shift, Blinking, and Blending tools. You can find these tools under the 'Tools' dropdown.

Watch this video tutorial to learn how to use these three tools:


Adjust the Color

Choose from this list of colormaps to either
add beauty to your image, or highlight the
relative brightness of different regions in your image.

You can also make real-color images with
RGB mode, but you ought to watch a tutorial
on creating RGB images first.


Save Your Images and Create a GIF

When you're done, save all your images to your computer or device. Go to a third-party website like, upload your images, set the animation rate, and download an animated GIF of your lunar eclipse.

Feel free to post your GIF to our Facebook, or post it to Twitter and mention us (@microobs). We can't wait to see what you make!


Close the Tutorial Image

Now that you've practiced using JS9-4L, close any images that you opened during this Guided Tour so you can start from scratch. Just click the × next to any image files that are currently open.

Remember: you can reopen images for this challenge under the 'Lunar Eclipse' tab.


Explore More

If you would like more detailed help, the button on the left will take you to a video tutorial on processing images.

You can also request your own images of the Lunar Eclipse (and other objects) using MicroObservatory telescopes. Just follow the button on the right.


You’re All Set!

But if you would like to watch this Guided Tour again, just click this button above.

Finish Guided Tour



Shift Image

Shift Image