Your telescope’s tube has some print somewhere that lists it’s focal ratio. That’s your speed limit when it comes to light. Your telescope’s focal ratio … Read More

Take the following scenario: You’re standing in your back yard looking through a telescope at some far off galaxy or maybe even Saturn with detail … Read More

For telescopes and solar panels, it is important to know angle between the point directly overhead and where the Sun sits. Because it’s all about … Read More

A lot of times you get your telescope out, line up on the stars, look around and find the object you wish to observe is … Read More

Sometimes you’re standing on a hillside and watching the sun set, and you know: that thing is going down. But where exactly does it go? … Read More

Unless you forget that the sky spins, right ascension feels backwards. Latitude and longitude are our measurements on the planet; up there, they use its … Read More

There is a spot in the sky with some light on it. It is a fuzzy smudge. What’s that? Oh yeah, you want to look … Read More

We live with a coincidence: The Moon and the Sun are about the same apparent size in our sky. They are not actualy the same … Read More

Orbital mechanics determine size of umbra, and that, in turn, tells us how large a shadow will be. That means you can use the umbra … Read More

The big moment arrives, it’s a full moon, you look up and ask yourself: How long will this eclipse be? You set alarms for the … Read More