Simulating an Eclipse with Celestia for Android

By

What would a lunar eclipse look like on the Moon?

Closeup of the Earth hiding the Sun in a simulation of the May 26, 2021 lunar eclipse seen from the Moon
Closeup of the Earth hiding the Sun in a simulation of the May 26, 2021 lunar eclipse seen from the Moon.

With Celestia for Android I simulated the May 26, 2021 lunar eclipse seen from the Moon. I screen-recorded a video on my ASUS Chromebox 3 while the Celestia app simulated the eclipse as seen from the lunar surface in an area near the North pole.

Standing on the Moon the phenomenon would appear as a solar eclipse, with the Earth moving in front of the Sun and hiding it. In the video time runs 1000 X faster, from 04:00 UTC on May 26 to 19:00 UTC. The frame has a field of view of about 21° vertically. Notice the surface darkening up to the horizon while the Earth covers the Sun and casts a shadow on the Moon.


How to simulate the eclipse

Celestia is the best universe simulation software.

To create the simulation, I used the Celestia app for Android on my ASUS Chromebox 3 not only because it runs well on Chrome OS but also because a crucial feature for this task requires an external keyboard on Android devices. A desktop system with a built-in keyboard is more convenient.

First off, to re-create the event in Celestia I set the date and time to May 26, 2021 at 04:00 UTC (06:00 CEST where I live), a few hours earlier than the eclipse.

This set the proper conditions for landing on the surface of our satellite at an observing site close to the North pole. Why there? Because at the poles the Earth is low on the lunar horizon and a narrow field of view can contain the Earth, the Sun, and the surface of the Moon.

Next, I switched to alt-azimuth mode, rotated the view to frame the Sun, and narrowed the field of view. Unless the field is narrow, the small discs of the Sun and Earth get lost in the background of the dark sky.

Switching to alt-azimuth mode, a key step that enables to rotate the view around a vertical axis as if standing on the Moon, requires a keyboard. Alt-azimuth mode helps to look around from the surface of other celestial bodies, such as viewing the rings of Saturn from the planet.

Finally, I increased the speed of time 1000 X to make the motion of the Earth in the sky apparent. To screen-record the simulation running in the Celestia window, I used the Nimbus Screenshot & Video Recorder Chrome extension.

Popular posts from this blog

Using a Bluetooth Keyboard on Android

By
Image
Two years ago I bought a cheap Bluetooth keyboard from Amazon.it. At €14, it was mostly an impulse buy for exploring mobile typing on the go and in similar settings , such as workstations with reduced desk space. My FREALL 7INKEYBD-BK Bluetooth keyboard. I initially used the keyboard with the Android tablet and smartphone I had, a 7” Lenovo Tab E7 and a Pixel 2 XL. I later repurposed the keyboard for the devices I replaced those with, a Lenovo Tab M8 HD 8” tablet and a Pixel 4 XL smartphone. Despite the simplicity of operation, it took me some trial and error to figure out how to pair the keyboard with an Android device and what keystrokes insert the characters I need, such as accented letters when writing in Italian. Moreover, I realized I never blogged about my experience with the unit. So I’m posting these notes in case you come across the same or similar keyboards. The keyboard The keyboard is a cheap, compact, plastic chiclet unit that comes with a small foldable stand for a ta...
Read more

Lenovo Tab M8 HD Review

By
Image
I bought a Lenovo Tab M8 HD , an 8” Android tablet. It comes with a MediaTek Helio A22 SoC, an IPS panel, 2 GB of RAM, and 32 GB of storage. I ordered the device from Lenovo’s Italian online store for €134. In this post I’ll share my early impressions on the device. The packaging box of the Lenovo Tab M8 HD tablet. Motivation The Lenovo Tab M8 HD replaces the Lenovo Tab E7 7” tablet I bought almost a year and a half earlier. After enjoying the Google Nexus 7 2012 and 2013 tablets I left Android slates for several years. My return to tablets with the November 2019 purchase of the cheap Lenovo Tab E7 was a sort of impulse buy. I wanted an affordable Android slate small enough to be compact but with a large enough screen to help productivity . I also figured it would double as an ebook reading device and let me explore the Android ecosystem. The Tab E7 was nice but limited. The screen didn’t have good touch sensitivity, performance was poor, there was a lot of lag, and the screen was no...
Read more

How to Add Code Syntax Highlighting to Blogger

By
Image
On my blog I always wanted to format source code in Python and a couple more languages, but couldn’t find a convenient way. Until I read a tutorial on adding syntax highlighting to Blogger blogs like mine. The Blogger post composer actually provides the monospace Courier font that may be used for source code, but it works well only for inline text . If I apply the Courier font to a block of code, the composer renders each line as a separate paragraph. This leaves too much vertical space that makes the code look ugly. A workaround is to switch to the HTML view in the composer and wrap the block within <pre> ... </pre> tags, which insert the correct line spacing. However, the code doesn’t stand out on the page and there’s room for improving its scannability and visual impact. Fortunately, Blogger is an old dog I can teach new tricks to, like the setup the tutorial I found presents. A Python code snippet with syntax highlighting rendered by highlights.js in a post of the Moo...
Read more