We live on a small rock racing through space. And our days are marked by the rising and setting of a star.
Beyond the Farthest Star
When you look up into the night sky, you are seeing into the past. Cosmic distances are so vast that it takes time for light to travel them. The brightest star in the night sky is Sirius, more than 8 light-years away, which means we see Sirius not as it is now, but as it was 8 years ago.
A Blanket Full of Sky
If you hang around astronomers for a while, you will soon hear about the problems of light pollution. Light pollution is one example of the challenges of Earth-based astronomy. Specifically the atmosphere that surrounds our planet.
What You Get is What You See
These images look very different from each other because they were observed by different instruments, that each detect different ranges of wavelengths of light. Just as our eyes are capable of observing a particular range of wavelengths, each instrument can only observe a particular range of wavelengths.
Earth in the Balance
Then of course there is the infamous egg balancing myth, which says you can balance an egg on its end the day of the equinox. You can do this with a little care and luck, as you can see in the picture, but you can do this any day of the year as well.
In the Way
If you happen to be in the central New York area, say between Syracuse and New York City, if you watch Regulus around 2am Thursday morning you might see the star disappear for about 10 seconds.
Rainbow Star
Spectroscopy is one of the most useful tools of modern astronomy. With it we can identify the atomic and molecular composition of celestial objects, we can measure the relative motions of stars, and we can observe the expansion of the cosmos. Modern telescopic spectroscopes generally use a device known as a diffraction grating.
Aberration
A simple telescope can be made from basic lenses or mirrors, but a good telescope must be designed to account for optical aberrations.
Scale
When something is far way, it can look quite small. That is why the resolving power of your instrument is so important.