Planetary Spacing Table
| Planet |
B–T value |
Actual value |
| Mercury |
0.40 AU |
0.39 AU |
| Venus |
0.70 |
0.72 |
| Earth |
1.00 |
1.00 |
| Mars |
1.60 |
1.52 |
| ? |
2.80 |
--- |
| Jupiter |
5.20 |
5.20 |
| Saturn |
10.0 |
9.54 |
| Uranus |
19.6 |
19.19 |
Neptune was not known at the time
European astronomers felt strongly enough about the reality of this unknown planet that they formed a team, nicknamed the “Celestial Police,” to search for it. However, a new body was spotted shortly before they could begin their organized search. On the night of January 1, 1801, team member Guiseppe Piazzi spied a starlike object that had moved slightly in the heavens near the Hyades and Pleiades star clusters. It was soon realized that it was a small body located near the same distance from the sun as was the “missing” planet predicted by the Bode-Titus law. It was eventually called Ceres.
Three other small bodies were discovered over the next few years, all lying about the same distance from the sun as Ceres. They were soon named Pallas, Juno, and Vesta. Over the years, many thousands of these small planetoids were found. They became known as asteroids.
Within the past twenty years, Ceres has been reclassified as a “dwarf planet.” The rest, including Pallas, Juno, and Vesta, are still referred to as asteroids.
Binocular Program: Tracking the asteroid Vesta in its orbital path
How to find Vesta (It will appear starlike, even through a telescope. Vesta will not be bright, but binoculars should reveal it.)
- Gaze towards the constellation Libra in the southeast 4 hours after sunset in the beginning of April, and 3 hours after the middle of April. See Map A.
- Alpha Libra, aka “Zubenelgenubi,” lies mid way between the bright stars Spica and Antares, and happens to be a good double star for those with very keen eyesight. Binoculars easily will show its two component stars next to each other.
- About 10º north of Zubenelgenubi is Beta Lyrae, aka Zubeneschamali, which is slightly brighter than the first Zuben. How far is 10º? Make a fist and fully extend your arm. The width of your fist is 10º. Place Zubenelgenubi immediately below your fist – Zubeneschamali should lie at its upper edge.
- See Map B
- Place Zubeneschamali at the extreme southern edge of the binocular field. Near the northern edge will be four dim stars forming a rectangle. Just west in the field is Vesta, which shows about the same brightness as the rectangle’s southeastern star.
- Follow Vesta each night as it moves westward. By April 27, it will have moved one binocular field west of where it was on April 1 and will sit next to a brighter star, 16 Virginis.
Track its changing position throughout April and into May. You will be following Vesta as it moves in its orbit like its discoverer, German astronomer Heinrich Wilhelm Olbers, did in 1807!
Note: Bright moonlight will significantly hamper observations between April 7 and 19.
Notes:
- Vesta is 325 miles (525 km) in diameter (15% that of our moon).
- On April 1, it lies 123 million miles (199 million km) from Earth, while on April 30 it will have dropped to 110 million miles (179 million km).