How many planets have you seen?

How many planets have you seen?

Now that the IAU has ruled that only Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune are planets, it's a lot easier to say you've seen them all then it used to be. Using the new definition I can proudly claim to have seen all of them, but...

Personally, I prefer a definition that includes the dwarf planets as full fledged planets. A dwarf planet is a small planet orbiting solo around the sun (as opposed to orbiting a planet) still big enough for gravity to pull it into a spherical-ish shape. This would nicely add Haumea, Makemake, Eris, and the subject of this post, Ceres to the list (plus quite a few more yet to be discovered, I'm sure). Ceres was discovered in 1801 by Giuseppe Piazzi. It was the first asteroid (or minor planet) to be discovered, and it resides in the Belt. Unlike some stars, our sun has only one asteroid belt, and it doesn't look quite like that one from the Empire Strikes Back, dang it. For a truly awesome look at the 200 largest bodies in the Solar System, including the dwarf planets, take a look at this image here. Really blows the mind.

We'll soon know more about what Ceres looks like when the Dawn mission reaches the dwarf in 2015 after visiting the asteroid Vesta. Currently the best view we have is a composite image from the Hubble Space Telescope which you see at the top of the page.

Although Ceres and all other asteroids don't look like anything more than a star-like point in amateur instruments and small scopes (thus the name from the latin), like much of amateur astronomy the thrill is derived from knowing what you are seeing. I have seen a few asteroids before, the easiest being Vesta, but I've yet to see a dwarf planet. Pluto is currently in Saggitarius and ~ magnitude 14, making it a real pain to track down until it moves to a less crowded constellation. The other way-out-there dwarf planets like Eris are too faint to see visually with amateur equipment. This leaves Ceres, shining brightly right now at about magnitude 6.7, beyond easy range of the naked eye but no problem for binoculars. During February Ceres is at opposition, meaning we are between it and Sol, and thus at the closest distance (about 1.5 AU). I created a finder chart using Cartes du Ciel, which you can download here if you would like to join me in my quest.

So soon I'm gonna say I've seen 9 planets :)