Shapes with Shadows – astrosketching Moon features with Alex Massey

Shapes with Shadows – what they can tell us

This the first of two special guest posts by Australian astrosketch artist Alexander Massey 

Live View Sketch of Moon craters Azrachel, Alphonsus, and Ptolemaeus by Alex Massey

Ptolemaeus, Alphonsus, and Arzachel… the names of three massive, interlocking craters on the Moon. These three craters tell the story of the ancient Moon’s creation and evolution. It’s a story of violent bombardments and oceans of lava. We can use light and shadows to reveal the shapes and deep history of these features.

Most people think of astronomy a science of light. But, light creates shadows when it hits things. Those features that lie in the shadows, the dark parts and seemingly just-in-the-way-of-the-light parts, are just as important as those that shine brightly. These dark shadows form most of the mass of all galaxies, house stellar nurseries, reveal old lava rivers on the Moon, and create curious plays of light and dark. These can play tricks on our eyes and make patterns appear.

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Walk to Mintaka

Physical Astronomy by Daniel Cummings
Mistakable rises toward the zenith as you walk toward the equator
As you walk toward the equator, Mintaka appears to rise higher in the sky.

In this post we will learn how to use one bright star of Orion’s belt to visualize the Earth’s equator.

Mintaka is a Star in Orion’s Belt

When you look up at the winter sky in the northern hemisphere, Orion and his famous belt are impossible to miss. The belt is made up of three stars of equal brightness.

One of these stars is called Mintaka and it is a guidepost for finding the Earth’s equator in space. Click here to continue reading…

Arms around the ecliptic

Learn to see the ecliptic

Physical Astronomy by Daniel Cummings

Ecliptic Arms

The sun follows the same path through the sky every day.

Sun up. Noon. Sun down.

The sun starts the day in the east in the morning, rises high in the sky at noon, and settles down again in the west for a nap at night.

See the ecliptic

Here is an exercise to discover that path – the ecliptic.

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Groundhog Day Shadow Tracker

Physical Astronomy Tool by Daniel Cummings

Groundhog Day Shadow Tracker Lesson Plan
It’s Groundhog Day!

What better way to celebrate Groundhog Day than to Build your own Groundhog Day Shadow Tracker


Sun Tracker Window Gel Cling and Stickers to track the Sun

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.

It’s called the Sun Tracker and you can purchase one right from this website.


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!

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A new star will appear in the sky in 2022

Binary star merge to form a new star - a star in a starAn amazing thing is about to happen! A Star in a Star will be born.

You  can witness the birth of a new star in the night sky.  The new Star already has a birthday: 2022!

According to scientists, the new star will form when two stars that are orbiting each other grow so close that they merge into one.

The new star will appear in the constellation Cygnus. You can see the approximate location marked by a red circle in the Stellarium screenshot here:

A screenshot of Stellarium showing the new star location under the constellation Cygnus's left wing

The image of the two blue stars on the home page of this Star in a Star site shows what scientists think it looks like now. This impressive video shows an artist’s rendering of the star merge.

In the pair, one star is larger than the other so in the end, there will be a new star…  A Star in a Star.

The Moon Dance – Learn Moon Phases

PHYSICAL ASTRONOMY BY DANIEL CUMMINGS

The moon dance helps you learn and understand the phases of the moonLearn the Moon phases by doing an easy dance.

At sunset.

Face the sun.

Point your right hand toward the Sun.

Now point your left hand toward the Sun.

Both hands should be pointing at the sun.

Now, turn a little bit to the left, keeping both hands pointing at the sun.

Swing your left arm out until it is pointing in the opposite direction from the sunset. Bring your hands together again and repeat this swinging motion.

Bring your hands together again and point them both at the sun. This time, instead of swinging, bounce your left hand, leftward, some number of times… (14 is perfect if you can do it) …until it is pointing in the completely opposite direction from the Sun at sunset. Your left hand should now be pointing East.

Was the moon at any one of those 14 hand bounce spots? That is the age of the moon in days.

Please post your questions in the comments!