What's New in Astronomy
The minor planet was one of
many discovered by astronomer Robert McNaught from Siding Spring
Observatory near Coonabarabran NSW. He discovered this minor planet on
28th September 1991 on a photographic plate taken with the 1.2m UK
Schmidt Telescope as part of the AANEAS (Anglo-Australian Near-Earth
Asteroid Survey).
The IAU (International Astronomical Union) officially named minor planet
1991 SH1, (18377) Vetter.
Citation: John Francis Vetter (b. 1945) is a retired automotive mechanic. He established the Mudgee Observatory in 2005 and through it shares his love of astronomy with the public and amateur astronomers.
(18377) Vetter orbits the Sun every 4.13 years at an average distance of 2.57 AU (1 AU = the average distance from Earth to the Sun) with an eccentricity of 0.19, putting it within the main asteroid belt between Mars and Jupiter. The diameter is estimated to be 10.8 +/- 0.2 km based on observations of its brightness and reflectivity.
Click this link to go to the JPL Small Body Database Lookup and see the orbit in 3D.
By popular definition, the Blue Moon is the second full moon to occur in any calendar month. The term "Blue Moon" has been used in the English language for over 400 years but there seems to be no reference as to why the second full moon should be referred to as blue. It certainly does not turn blue in colour. An average month is around 30.5 days and the average interval between full moons is 29.5 days so it makes the incidence of two full moons in the one calendar month a rarity. Every century there is an average of 41 months that contain two full moons which makes an average of two-and-a-half years between Blue Moons. So we have the term "Once in a Blue Moon" used today to indicate that something occurs "not very often". At the other extreme February is the only month that can miss out on having a full moon and this only occurs four or five times every century.
The Sun is 400 times larger than the Moon but because it lies 400 times further away they appear to be the same angular size in the sky (about 1/2degree), so that it is possible for the Moon to totally cover the Sun's disc. If the Sun, Moon and Earth lie directly in a straight line then a total or annular eclipse will occur. If the Moon's orbit around the Earth was to lie in the same plane as Earth's orbit around the Sun there would be a solar eclipse every new moon and a total lunar eclipse every full moon. The two planes are however inclined at an angle of 5 degrees, intersecting only at the nodes of the Moon's orbit and this is when the eclipses can occur.
WARNING:- Under no circumstances should you try to observe the Sun without the correct solar filters... or serious eye damage will occur.