Don became interested in astronomy at age 8. He received his 1st telescope in 1965, a 2-inch (5cm) refractor. Later he received a 6-inch (15 cm) Criterion Dynascope and found all the Messier Objects in one year (1969-70). He began his 1st comet hunting program in 1975 and found his 1st comet in 1978, after 1700 hours of searching. His 2nd comet took an additional 1742 hours. He ultimately discovered a total of 12 comets, which bear his name. In 1978, Don was one of the independent inventors o...| earthsky.org
What is a variable star? Astronomers know millions of them, and you might find one in any part of the sky. Among the stars in this image of the central region of the Milky Way galaxy, there are 2 known Cepheid variables. They vary due to internal changes in the star. Image via ESO/ VVV consortium/ D. Minniti.Many stars are not constant| EarthSky
The brightest stars to the eye are 1st magnitude, and dimmest stars to the eye are 6th magnitude. How does stellar magnitude work in astronomy?| EarthSky | Updates on your cosmos and world
Some extremely large and hot stars blaze away with the luminosity of a million suns! But other stars look bright only because they're near Earth.| EarthSky | Updates on your cosmos and world
Use this “handy” guide to measure degrees – or sky measurements – on the dome of the sky. Image via timeanddate.com. Used with permission.How do you describe how far apart something is in the sky? The fact is, the handiest measuring stick for the sky’s dome is the one on the end of your arm. You can use the width of your pinky, fist and more to gauge the distance between sky objects. That comes in handy when you’re observing conjunctions between planets, or close planets and stars...| EarthSky
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