Asteroids

Asteroids are small rocky bodies predominately found in the region between the orbits of Jupiter and Mars which is called the “Asteroid Belt”. It is believed that they are remnants from the formation of our solar system and are perhaps the remnants of “failed planet” that tried to form in this region. There are approximately 750,000 asteroid type objects cataloged in the solar system that vary in size from tens of meters in diameter, to the largest of the asteroids – Ceres – which has a diameter of 625 miles. Though a telescope asteroids look like any other star and can vary in brightness depending on their size and distance from earth. The best way to view asteroids is to use a star chart and find the object that doesn’t match the stars shown on the chart, or you can make a sketch or take a photo of the area and come back in a few hours or a day and repeat the process to see what object has moved. There are videos on my Videos Page which highlight the movement of several asteroids that I have observed.

Ceres is the largest of the asteroids and the first one discovered (1801). At 625 miles in diameter it makes up fully 1/3 of the total mass of known asteroids.
Vesta is the second largest asteroid with a diameter of 326 miles. It was the fourth asteroid to be discovered (1804)
Pallas was the second asteroid to be discovered (1801) and is the third most massive asteroid after (4) Vesta. Pallas has a diameter of 318 miles.
Juno was the third asteroid to be discovered (1804) but only 11th largest and with only 3 percent of the mass of Ceres. The photo above is a composite of two frames which shows the movement Juno over a period of 65 minutes.
(7) Iris is the fourth brightest asteroid after Vesta, Ceres, and Pallas but was not discovered until 1847. It has a diameter of 149 miles. It the photo it is shown in conjunction with the double star 5 Arietis.