Skynotes: September 2019
Great Melbourne Telescope Restoration
The dedication and expertise of the volunteer team working to restore this historic 19th century telescope continues to impress all who hear about the project.
The Great Melbourne Telescope was an important icon for nineteenth century Melbourne, signifying a transition from a colonial outpost, to a progressive city, with an interest in science and astronomy. It was the first large telescope with an equatorial mount and clockwork drive, allowing automated tracking of celestial objects. This year the telescope celebrates the 150th anniversary of its installation.
The telescope is now being restored to its original 1869 condition, as a fully functional observational telescope, to be returned to Melbourne Observatory in the Domain for public viewing.
The telescope restoration works can be seen from the Scienceworks Engineering Workshop viewing area, accessible from the Pumping Station courtyard. On Tuesdays and Thursdays a team of volunteers actively work on the restoration.
Month highlights
We pass through the Spring Equinox this month when day and night are equal (see below), and enjoy a wonderful evening combination with Jupiter, Saturn, the red giant star Antares, and Scorpius all close together high in the west.
Planetarium events
Planetarium Nights | Friday 6, 13, 20, & 27 September
Evenings for adults
7.30pm – The Hot and Energetic Universe + What's in the Sky Tonight
9.00pm – Elemental
Melbourne sun times
| Date | Rise / Set times (daylight) |
|---|---|
| Sun 1st | 6:42am / 5:58pm (11:15 hrs) |
| Wed 11th | 6:27am / 6:06pm (11:38 hrs) |
| Sat 21st | 6:12am / 6:15pm (12:02 hrs) |
| Mon 30th | 5:58am / 6:22pm (12:24 hrs) |
Moon phases
| Phase | Date |
|---|---|
| First Quarter | Friday 6th |
| Full Moon | Saturday 14th |
| Last Quarter | Sunday 22th |
| New Moon | Sunday 29th |
The Moon will be at perigee (closest to Earth) on Sat 28th at a distance of 357,802 km, and at apogee (furthest from Earth) on Fri 13th at 406,377 km.
Planets
Mercury is very close to the Sun, as viewed from Earth, but from mid-month it may be seen low in the west at twilight.
Venus returns to the evening sky from mid-month visible very low in the west after sunset.
Earth days are warming up again as we pass the Spring (or Vernal) Equinox on Sunday 23rd at 5:50pm when Sun crosses the celestial equator heading south. It is often said that day and night are equal on the equinox, but this is not quite so. Only the centre of the Sun is above the horizon for 12 hours, making our day slightly longer at 12 hours and 8 minutes. Not only does the day start with the first appearance of the Sun, but there’s another strange effect occurring as well. The Earth’s atmosphere bends light from the Sun so that at sunrise we are able to see the Sun before it physically crosses the horizon. The reverse occurs at sunset, we continue to see the edge of the Sun for several minutes even though it has already sunk below the western horizon. When is day and night equal? On Thursday 20th, a few days before the equinox.
Mars will be on the far side of the Sun this month but will reappear in the east as an early morning object in November.
Jupiter is high in the western sky very close to the red giant star Antares in Scorpius. In the Boorong tradition of north-western Victoria, Jupiter is Ginabongbearp, a chief of the Nurrumbunguttias or old ones who created everything on the land.
Saturn with its slightly yellow glow can be found high in the north-west very close to the handle of the ‘Teapot’ (or bow and arrow of Sagittarius the archer).
Meteors
September is a poor month for meteors. The Southern Piscids is the most active shower and while it has an extended peak which runs from the 11th to the 20th, it only produces a few meteors per hour. The meteors appear near the constellation of Pisces, the fish, which can be found in the north-west from midnight until dawn.
Stars and constellations
In the early evening, the Southern Cross can be seen in the south-west, tipped over on its side, with the Two Pointers almost vertical above it.
Turning towards the south-east we see the bright star Achernar, which marks the end of the river, Eridanus, and also Fomalhaut, the brightest star in Piscis Austrinus. High in the north are the three main stars of Aquila, the Eagle, including the bright star Altair, while low to the horizon is Vega, the fifth brightest star in the night sky.
Directly overhead at sunset, the curl of the Scorpion’s tail can be seen near the teapot shape of Sagittarius. The Milky Way spans the sky overhead, looking splendid as it stretches almost north-south.
International Space Station
ISS orbits every 90 minutes at an average distance of 400 km appearing like a bright star moving slowly across the night sky. Here are some of the brightest passes expected this month over Melbourne and Central Victoria:
Fri 6th 7:35pm–7:38pm SouthWest to SouthSouthEast
Mon 9th 6:43pm–6:50pm SouthWest to NorthEast
Sat 28th 4:33am–4:37am NorthWest to SouthEast (early morning)
For predictions go to the Heaven's Above website.
On this day
1st 1939, Americans J Robert Oppenheimer and Hartland Snyder publish the first paper that describes the gravitational contraction of a star which led to the modern concept of black holes.
1st 1859, Carrington Event, most powerful geomagnetic storm ever recorded. A Coronal Mass Ejection from the Sun hit Earth’s magnetosphere inducing strong northern auroras almost to the equator, and telegraph interference in Europe and North America with operators receiving electric shocks, poles sparking, and messages sent despite power cut off.
1st 1979, Pioneer 11 (USA) made the first flyby of Saturn returning the first close-up images of the planet. It was the second probe to pass the asteroid belt and Jupiter and to reach solar escape velocity. Last routine contact was on 30 September 1995 and final data received was on November 1995.
5th 1977, Voyager 1 (USA) is launched to explore the outer Solar System. After 42 years it continues sending data and is the most distant probe at 21.8 billion km (146 AU). It entered interstellar space in 2012 and its power supply may last until 2025.
8th 2004, Genesis (USA) probe crashes in Utah while returning samples of solar wind particles. Some collecting panels survived impact and were recovered giving successful scientific results.
11th 1985, the International Cometary Explorer or ICE (USA) became the first spacecraft to encounter a comet by flying through the dust tail of Comet Giacobini-Zinner.
14th 1959, Luna 2 (USSR) was the first craft to fly to and impact another body, in this case the Moon. It released sodium gas to allow visible tracking, used radio for telemetry transmission, and crashed into Mare Imbrium (the Sea of Rains).
17th 1976, NASA unveils its concept for a Space Transportation System, a rocket launched and glider return orbiter known as the Space Shuttle.
17th 1857, birth of Konstantin Tsiolkovsky, a pioneering Russian then Soviet teacher whose theoretical work on aerodynamics and rocketry influenced all who followed. He advocated spaceflight and believed humans would colonise the galaxy.
18th 1977, Voyager 1 (USA) sends the first image of Earth and Moon together taken, from a distance of 11.6 million km while on its way to Jupiter.
21st 1633, the Roman Catholic Inquisition begins its trial of Galileo for heresy in publishing and advocating a heliocentric or Sun-centred solar system contrary to church doctrine, dogma and scripture.
23rd 1846, Neptune, first predicted by Urbain Le Verrier (France), is discovered by Johanne Gottfried Galle (Germany) with John Couch Adams (UK) recognised for an independent discovery.
27th 1905, Albert Einstein published his paper containing the famous equation E=mc2 (energy equals mass multiplied by the speed of light squared), meaning a small amount of matter is equivalent to, or can be converted into, a great deal of energy.