🔭 I am a Live Planetarium Presenter – “Planetariumist” – at the Fresh Air Fund’s Gustafson Planetarium at Sharpe Reservation in Fishkill, NY. We Planetariumists are learning to use Stellarium scripts. This article will teach you how to use a Stellarium script to quickly load the art images for the 13 Zodiac constellations:
Aries Taurus Gemini
Cancer Leo Virgo
Libra Scorpius (Ophiuchus) Sagittarius
Capricornus Aquarius Pisces
Online Camp programs for Astronomy Education
Like every other camp program during COVID-19 times we have had to move the live shows to an online format. In our case we are doing zoom astronomy presentations for the campers. It’s been a great experience to learn how to do quick and entertaining astronomy shows online and I wanted to share a few tips to make better astronomy online presentations.
Stellarium Scripts for Astronomy Zooms
I want to make Stellarium really work for online presentations like zoom astronomy outreach, so I figured out how to write scripts to control it. To get started, I just copy-pasted and modified an existing script that did something like what I wanted it to do.
Stellarium scripts help you do the tedious set up and configuration steps. There is no need to open windows and drag and click around while your audience waits!
Below is a Stellarium script I adapted from the original zodiac.ssc that highlights the Zodiac constellations with art, names, and boundaries and it shows the ecliptic. The original script that comes with Stellarium had some features that I didn’t need so I copy-pasted a new one. My new script simply shows the Zodiac constellation art in just 5 seconds. This would take at least a minute to complete by hand! So, this is a great timesaver if you are presenting to a group via online zoom conference.
Stellarium Script – show Zodiac Art, Boundaries, Ecliptic
You can click here to download the script as a zip file. Unzip this download and you will have the .ssc file in your downloads area. Or you can just copy-paste the text below and create your own script file.
Here is a quick gif animation of what the presentation screen looks like while loading the Zodiac Art Boundaries and Ecliptic in the Stellarium Astronomy Zoom presentation.
Using the New Zodiac Art Boundaries and Ecliptic Script – Tutorial
Installing scripts is as easy as creating a text file with this script and placing the “script_name_here.ssc” file in the scripts directory. In this case, name your script file: zodiac_art_boundaries_ecliptic.ssc
After this “Zodiac Constellation Art Boundaries Ecliptic” script is installed in your Stellarium you’ll be able to get to it and run it from the Scripts tab of the Configuration window.
Instructions to Install a Stellarium Script
On Windows: You have to find the Stellarium User Data directory and inside that will be the scripts directory. (NOTE: I don’t have a windows machine so there is probably more information required here. Please add a comment to this post if you discover that I have left something out.)
If it doesn’t already exist, create a new folder named “scripts” – leave out the quotes.
Move your downloaded or created .ssc file to this folder.
On Mac: you have to control-click (hold the control button and click the mouse) the Stellarium.app in the Applications directory and choose “Show Package Contents”
You then navigate to the scripts directory in: Contents > Resources > scripts.
Place the script file in the scripts directory. Quit and re-open Stellarium and the script will be in the list of scripts in the Scripts tab of the Configuration window (see graphic above earlier in the article).
If you want to be fancy and use the included key command …
Using Stellarium Script Trigger “Sequence” commands
This custom Stellarium Script comes with a key command I programmed which is a “sequence command” – two steps. First do Control/Command-D, then release those keys and type the letter z key.
Try out the script and let me know what you think by typing in the comments field below! Also, if you want me to write a custom script to speed up your Stellarium presentations I’d love to help out – give me your suggestions.
Stellarium is a potent tool to help you see the sky
I have written few other articles about using Stellarium.
About the author of this Stellarium script tutorial
🔭 Hello! I am Daniel Cummings – the creator of the fun and fashionable science clothing The Moon Hat (Forbes named it Best Science Gift in 2018). I am also one of the Live Planetarium Presenters – “Planetariumists” – at the Fresh Air Fund’s Gustafson Planetarium at Sharpe Reservation in Fishkill, NY. I’ve written about and presented astronomy and space topics since 2008. Sign up on my email list to hear more about astronomy and space.
It’s a skeleton key to the sky. It’s a poster. It’s a tome.
Guy Ottewell’s Zodiac Wavy chart poster.
This poster is HUGE. 24 inches wide x 36 inches tall. Also, it’s glossy and beautiful and full of engrossing details. You will return to this poster month after month and dwell on the intricate and scientifically-accurate renderings.
It is like a Moon Calendar but it shows the actual Moon position as well as its phase and date – plus it includes everything else in the sky. Best of all, it adds the “backdrop” of the zodiac constellations so you can see how everything moves among the stars.
The Zodiac Wavy Charts poster portrays the wildness of the Moon and its dynamic motion through the sky – all in a beautiful, informative, and rewarding wall hanging.
Guy Ottewell’s Zodiac Wavy Charts is a snapshot of the calendar month. Every day’s events are “layered” onto a wavy band. Think of those wavy charts in 3-dimensions: You can pluck one off the page, stitch it together into a ring, enlarge it, and step inside it and you’ve got a view of the most interesting and active sky chart you’ve ever seen!
It’s Better than a Moon Calendar
In a standard Moon Calendar the day squares contain the Moon phase images. The Moon images can be arranged artfully, but mostly they are placed to make the Moon conform to the month; the Moon gets “captured” into our cultural calendar. You can see the phase and the day the Moon phase will happen. This is good as far as it goes… but the Zodiac Wavy Charts poster is 100x better!
Guy Ottewell’s Zodiac Wavy Charts can tell you the day the Moon phase will happen. Also, it shows exactly where in the sky, and in which part of the Moon’s orbit it will happen. It tells you which part of the Moon is titled toward you, if it’s in an ascending or descending part of its orbit, and what constellation it is in.
This yearly calendar packs information that will teach you how to observe and will help you make sense of the sky. It’s like having an expert astronomer on-call all year long.
If you don’t have a Zodiac Wavy charts poster yet – you can order it here at Universal Workshop. The rest of this article will help people use the deep details on the poster to understand the motions of sky objects.
Quickstart Guide – Using the ZOD poster
Note: the Zodiac Wavy charts poster shows a northern hemisphere viewpoint. All writing here assumes you are in a northern hemisphere location.
Before you read this guide, please read Guy Ottewell’s text at the bottom of the poster. It explains many of the key items visible in the chart and serves as a legend. Guy’s writing provides a wonderful tour of the deep information revealed by these charts.
Unique Design Elements Tell the Story
Guy uses clever graphic design techniques to communicate how things move in the sky. For instance, to indicate how far the Sun moves in a month he expands the Sun with concentric rings. This clearly shows the sky location on the 1st of the month (the right edge of the outer yellow ring), the 16th of the month (the central Sun image), and the last day of the month (the left edge of the yellow ring).
Another unique design element (a variable-size red triangle) indicates the Moon’s current libration – tilt – towards or away from the Earth. Knowledge of the Moon’s libration helps observers see hidden Moon formations.
Guy also has prepared a detailed list of celestial events throughout the year that you can use to pinpoint on the Zodiac Wavy Charts. The Astronomical Calendar Any Year (or ACAY for short) has a FREE listing of celestial events. You can download the year’s worth of observing data in a PDF file from Guy’s website Universal Workshop.
Read the Charts from Right to Left
The Sun, Moon, and planets move (in general) from right to left across the sky. So too the Zodiac Wavy chart should be read from right to left. You can see the Moon phase images (and day numbers) grow from right-to-left. You can observe that the Sun moves from right-to-left over the month.
Sometimes when the Moon “overlaps” itself during a calendar month, the numbering looks a little funny – this happens because the calendar month is not the same as the Moon phase month (except February) the calendar month is always longer. This article about Blue Moons shows what happens when we try to squeeze the Moon into our monthly boxes.
The first and last wavy charts have lots of text indicating the constellation names, but the middle charts leave them out for clarity. If you want to find out which constellation a celestial object is “in” you can refer to the January or December charts.
Start with the Sun as the Anchor
Use the Sun as the anchor for understanding how to read the charts. Look to the left of the Sun image in each month. The space spanning 6 constellations to the left (east) of the Sun shows you the night sky at sunset. The space spanning 6 constellations to the right of the Sun shows you the pre-sunrise sky. The midnight sky is always centered about 6 constellations to the left of the Sun. You can imagine the whole of the night sky by centering your eye on the anti-Sun which shows the location of midnight on the 16th of the month.
The Sky at Midnight – Anti-Sun and the Full Moon
The anti-Sun indicates the meridian (the middle of the sky) at midnight. The anti-Sun also moves from right-to-left through the sky. It could be displayed with the same-sized concentric Sun rings. It marks midnight and you can see that the Full Moon is always close by.
Tilt the Poster to Line Up with the Sun
Here’s a fun idea: turn the poster sideways and place it on an east or west wall at sunset to “see” the star band lined up with the rising “anti-sun” (east wall) or the setting “sun” (west wall). Anchoring to the Sun or the Anti-Sun may help you visualize how the Zodiac Wavy Charts poster shows you the whole sky of Zodiac constellations all at the same time.
Why is it Wavy?
The meaning of the waves. It’s easier to imagine this if you think of the Equator as the horizontal and the plane of the solar system as tilted.
Eclipses – Every Six Months in the Same Sky
The location of eclipses = the location of node crossings = the location of the nodes = changes very, very slowly (18 years, 11 days, 8 hours to be exact).
Look at the eclipses – there are a few of them every year and 2019 is no exception! Notice that they all occur during the New Moon or the Full Moon and that they all occur in the constellations Gemini or Sagittarius. The reason the eclipses happen while the Moon or the Sun are in Gemini or Sagittarius is because of the Moon’s orbital nodes. These nodes are “in” these two constellations this year.
It’s not just the Moon that orbits the Earth, the Moon’s orbit nodes themselves actually orbit the Earth. This orbit of the nodes takes 18.6 years! The intersection with the lunar phase cycle and the orbit of the Moon’s apsides is the source of the famous Saros interval – where 2 similar eclipses occur.
So, if you buy the Zodiac Wavy Chart poster for the next 18 years, you’ll see the Moon’s orbital nodes – the location of eclipses – move through each of the fixed constellations!
Retrograde Motion – See it!
Planet motion is cool. Planets close to the Sun never cross the anti-sun, but outer planets do. This confused our ancient ancestors who did not realize that the planets were following an orbital path around the Sun at the same time that the Earth was following its own orbital path.
These two motions (the planet’s and the Earth’s) made it look like the planets sometimes moved backwards (retrograde)! You can find all of the retrograde motions easily and see exactly when and where they will happen.
Measurement – by Counting Constellations
Degree marking – the charts lack any of the standard degree measurements (Right Ascension/Declination or Altitude/Azimuth). This type of measurement is not really necessary for general use of these charts. This is because you can find these measurements in other places.
However, you may want to understand how big each section of the sky is compared to each section of the chart. You can think about it like this: there are 12 zodiac constellations (13 if you count Ophiuchus) and they span 360 degrees of the sky. We can see a bit less than 180 degrees of the sky at any one time so that’s about 6 visible constellations! Just count about 6 constellations and you’ll get about half the sky!
If you divide 360 degrees by 12, you get 30 degrees. So, an average constellation covers about 30 degrees of sky. And the sky moves at a rate of about 15 degrees per hour. That means it will take about 12 hours for the sky to completely change.
Want to figure out how big something is? Use your outstretched hand as a measuring tool. The distance from your thumb to your pinky (when your hand is fully-stretched out) is about 25 degrees – a little less than the average constellation width.
One interesting after-effect of rendering the Sun’s position in this “wavy” way is that you can see an aspect of the analemma. The slight movement in the Sun’s position month over month traces a very slim half-analemma shape across the poster. There is a very slight speed up and slow down that you can see if you look closely.
Here is an image of the poster showing the slight but noticeable curve that the Sun makes.
Sidereal Map – the Stars Stand Still
These Zodiac Wavy Charts create a sidereal map of the sky. Sidereal refers to the fact that the background of stars remains fixed through every chart while all the other objects move through them.
What do you see?
There are hidden treasures all through this gorgeous image. Share them with us when you find them!
Frequently Asked Questions
Why is the Zodiac Wavy Chart wavy? The charts are wavy because Guy wanted to show what was happening at the ecliptic. The ecliptic is tilted at 23.4˚ from Earth’s pole (90˚ from the equator). So, sometimes objects in the ecliptic are below the equator and sometimes they are above it.
What is the Zodiac? The zodiac is the collection of constellations that define the ecliptic. The zodiac constellations define a band of sky where the Sun, Moon, and planets can always be found. Fun fact: Zodiac comes from the same root word that Zoo does – and it’s called that because many of the constellations are animals.
Is this an astrology tool? No, this is a visual astronomy tool. Astrologers will certainly find this a useful poster to refer to, but it is designed for visual astronomy observation assistance.
What can I use this for? This astronomy poster is useful for many things! Mostly, it’s a beautiful wall hanging that will draw your eye and reveal the deep celestial mechanics behind our Earth’s motion through the solar system each year. It’s also a wonderful conversation piece. Try telling people “It’s like a Moon Calendar, but it works for everything else in the sky too!”
Can I order this Zodiac poster internationally? Yes – you may have to pay a little extra shipping and sometimes customs duties, but the poster can be shipped almost anywhere.
Does the site accept purchase orders? No, Universal Workshop does not accept purchase orders. You can pay by credit, debit, or paypal.
Can I order a 2020 poster now? Yes! Please contact Guy [at] Universal Workshop [daht] com or visit UniversalWorkshop.com and make a comment on one of the recent blog posts.
Can I order in bulk? Yes! Contact Guy Ottewell for details.
You can see Venus in the sky at two times and locations:
in the early evening, shortly after sunset in the west or
the early morning, shortly before sunrise in the east.
Venus orbits the Sun and moves from evening sky to morning sky and back again over the course of about 18 months. Venus makes beautiful sweeping motions in the sky that reveal secrets of the solar system.
The orbits are all in the same plane. It’s like they are all marbles circling around the sun on the same giant plate. This is called the “ecliptic” and it is visible in the sky if you know how to find Venus.
Intersecting space planes
The “space plane” is not an airplane
The “plane” is a tool you can use to see the way things move in space. This “plane” is not an airplane, but a flat slice of space.
Here is an image of two intersecting planes. Imagine the blue plane is the earth’s surface and the brown plane is up-and-down from ground to sky.
Each object (and movement) in space creates a “plane,” an imaginary slice through physical space. The blue “plane” above looks like the surface of a pond, lake or ocean. A wall or roof of a house is a plane. A dinner plate is a plane. Stretch your arms out and spin in a circle and you have created a plane with your arms.
There are planes in space everywhere.
Your own personal space plane
You create a plane with your vision and balance. You can imagine a flat surface like the surface of a pool of water and your eyes are just above the waterline. This surface moves and tilts when you move your head.
Your head has two eyes that define your plane of vision. Also, your body is oriented to gravity because of your sense of balance – the “personal horizon” is the first plane for you to orient to. Your body naturally coordinates your visual sense with your sense of balance and gives us the sense of being located level on a surface. This is the “sense of horizon.”
A new horizon – choose a plane!
To get good at Physical Astronomy, we have to learn to coordinate our main “personal horizon” plane with other planes of the earth, moon, solar system, galaxy, and universe.
The earth for instance, has a lot of planes, the range of latitudes, the north and south poles, the Arctic and Antarctic circles, the equator, the tropics, a range of longitudes, the prime meridian, the international date line, the ecliptic, the galactic plane and more.
To keep things simple, let’s focus on just one other plane for now: the plane of the solar system. A wonderful thing will happen when you learn to link the plane of vision with the plane of the solar system. It’s pretty easy to do, and it’s a skill that gets better with practice.
The key to linking vision and solar system planes is to know that the plane of the solar system is visible as the ecliptic. One easy way to see the plane of the solar system is to see the bright inner planet Venus.
See Venus and the Orbit of Venus
Venus is closer to the Sun so we are able to see its entire orbit. Actually, we can’t quite see the entire orbit because sometimes it goes in front of the sun and sometimes it goes behind the sun.
We can see Venus in the early evening and in the early morning. Venus is visible in our sky when it is at the left and right extent of its orbit around the sun. We only see Venus in the sky when it is swooping around the left or right of the sun.
If you want to see the orbit of Venus and see the plane of the solar system you can do it! All you have to do is imagine a line connecting Venus to the Sun.
If you are looking at Venus early in the morning before sunrise or early in the evening before sunset, the process is the same. Imagine a line connecting Venus to the Sun; this is the ecliptic. Venus’s entire orbit covers roughly 1/4 of the sky.
We learned about two main planes in space: your personal horizon (which changes as the Earth carries you around the Sun) and the plane of the solar system: the ecliptic.
By learning to visualize these two space planes, we can begin to experience the extremely large dimensions of space.
One Day of Observation: the Sun rises and the Sun sets
Let’s start with a few easy observations about daytime. These are things you can notice just by waking up early one day before the Sun brightens the night.
The Sun starts the day for us on one side of the sky and ends the day on another side. At both of these times (sunrise and sunset), the Sun appears near to the ground – at the horizon.
During the middle of the day, the Sun appears to move “up” and across the sky and then back “down” again. In the middle of the day – at noon time – the Sun is high up in the sky, away from the ground.
Shadows change during the day
In the morning the Sun makes long shadows. At noon the Sun makes short shadows. At the end of the day, the Sun makes long shadows again.
With a few simple tools you can measure the Sun’s position and shadows.
The Sun moves east to west
Over the course of one day, the Sun appears to move across the sky from east to west, rising to the highest point at noon. The Sun’s light shines on the Earth and makes shadows that move and change position and size. As the Sun “moves” through the sky, the shadows move on the ground.
Build a simple sundial, track the Sun
A sundial tracks the shadow of the Sun with an object that casts a shadow and time markings. For the simple sundial you can use a stick. The shadow of the stick (the stick on a sundial is called a gnomon) moves across the sundial. The shadow of the stick points to the time markings.
The simplest sundial is just a stick stuck in the ground with time markers nearby. The location of the stick’s shadow moves across the time markers throughout the day.
Mark the shadow’s position with any object (chalk drawing, a rock or another stick is a good choice). In the morning, the Sun appears low in the east and the shadow is long. The morning shadow points toward the west. At midday (noon) the Sun is at the highest point so the shadow falls in the middle and becomes short. At sunset, the shadow becomes long again – pointing to the east.
Paper Plate Sundial
A paper plate with a pencil stuck through the middle makes a great moveable sundial! (Remember, when you move a paper plate sundial, you have to be careful to place it in perfect north-south alignment.)
Take this outside on a sunny day, then make a mark on the paper plate at the top of each hour. The shadow will move slightly each hour. The mark should go at the middle of the pencil shadow.
When you have completed this during one sunny day, you have made a sundial that can tell the time – roughly speaking!
An indoor sundial – the Sun Tracker
Most people think of sundials as something that you place outside. But, the Sun shines inside through windows. You can track the Sun through a window.
An indoor sundial can help you track the Sun from the comfort of your own home! Do you have a sunny (or partly sunny) window? You can track the Sun and reveal the secrets of the Earth’s motion.
The Sun Tracker is an easy-to-use indoor sundial. Place the glistening window cling on any sunny window and then mark the position of the window cling’s shadow using one of the included stickers.
Repeat the next day or the next week at the same time of day. You will see a pattern emerging: the shadow cast by the Sun moves quite a bit each day.
If you are extra precise with recording the shadow at the same time of day, and you are able to do it for an entire year… you will see the Analemma.
The Sun Tracker is like a little bit of Stonehenge for your window.
Track the Sun with simple tools and you will reveal the motion of the Earth. There are two main motions of Earth, daily rotation and yearly orbit. Earth spins under the Sun each day and around the Sun in an orbit each year.
It is these two motions that make the Sun seem to move in the sky. Remember that the next time you are looking for the Sun – it’s where it always is… the Earth is what moves.
Learning to do Physical Astronomy? Stellarium is the perfect tool for you. It helps you learn to see patterns in the sky. In this article you will learn how to use the Time Control features of Stellarium.Click here to continue reading…
UPDATE: We now sell an astronomy gift called the Sun Tracker that teaches you the same Basic Astronomy Lesson that the Ground Hog does! You can learn all about the apparent movements of the Sun and the analemma.
Let’s do some Physical Astronomy. The experience will help you to understand the movement of the earth and sun through the seasons. You will build a scientific instrument that is also a fun garden decoration and you will be able to track the Groundhog’s Shadow all Spring!
Wished that the sky had labels on everything? Stellarium has 10 different label types.
Stop time? Move time by day, by week? Do you want to see what will happen in 2 months? Or look at the sky during the Pharoah’s reign? You can time travel.
You can easily drag and zoom, stop time, go in reverse, make a timelapse, follow the moon through its phases. You have a tool to help you understand the ecliptic and sidereal time and retrograde motion. You can see the great orbital swing of Venus as it circles the Sun.
Ok! I’m convinced by your Stellarium review. What should I do now? What’s my call to action?