solar sibling in Hercules

Astronomy & Observing News

Through Sunday: Get That Star Atlas Cheap!

Most of the things that are visible in any telescope, big or small, are barely visible in that telescope. You can't pick them up just by sweeping. You have navigate to the precise spot.

Star Wheel

Stargazing Basics

How to Make a Star Wheel the Simple Way

Would you like to be able to navigate your way around the night sky with confidence? Using this simple, easy-to-make Star Wheel, you can "dial the sky" for any time or date.


Astronomy Questions & Answers

How many digits are satisfactory in the measurement of pi?

In the 3rd century BC, Archimedes proved that the ratio of a circle’s circumference to its diameter is less than 3 1/7 but larger than 3 10/71. That’s about 3.141. Later mathematicians have computed what we now call p (pi) to greater and greater accuracy — but how many digits…

Astronomy Questions & Answers

When will (or did) the galactic equator cross the ecliptic very close to the latter's northern and southern extremes?

As a teenager, when examining an equinox-1950 star atlas, I noticed that the galactic equator crossed the ecliptic very close to the latter’s northern and southern extremes (that is, the solstices at right ascension 6h and 18h). On equinox-2000 charts they are even closer. I’d love to know when the…

Hobby-based Q&A

Were stars artistically depicted with diffraction spikes before the invention of the Newtonian reflector?

Were stars artistically depicted with diffraction spikes before the invention of the Newtonian reflector? If so, why? Stars were being drawn with points or spikes long before Isaac Newton announced his reflecting telescope in 1671. Just look at early works of art, flags, ancient coins, and the charts of the…

Venus Ring of Light

Astronomy Questions & Answers

How did early astronomers calculate accurate solar system positions?

In the pre-computer age, say 50 years ago and back, how did astronomers calculate accurate positions of the Sun, Moon, and planets for predicting an eclipse or a transit of Venus? They did it by hand, with the help of numerical tables. These weren’t the trigonometric and logarithmic tables you…