The term ‘Supermoon’ is a nickname for a perigee full moon, this is the when the Moon is  closer to the Earth than usual in its orbit. Apogee and perigee refer to the distance from the Earth to the moon. Apogee is the furthest point from the earth while Perigee is the closest point to the earth and it is in this stage that the moon appears larger. Looking at the moon in the sky without anything to compare it to, you wouldn’t notice any size difference. But the difference in size can in fact be quite significant.

If you were to take a picture when the Moon is at perigee and again at apogee using the same camera and lens you would notice the difference.

The full Moon occurs at 1:35pm (AEST) Sunday May 6th in Australia. It is predicted that the moon will about 14 per cent brighter than usual.

Sunday’s event is a “supermoon,” the closest and the biggest and brightest full moon of the year. At 1.35 p.m., the moon will be about 356,956 km from Earth. That’s about 24,653 km closer than it is on average.

That proximity will make the moon appear about 14 percent bigger than it would if the moon were at its farthest distance, however, the difference in appearance is so small that you will find it hard pick it with your unaided eye.

The moon’s distance from Earth varies because it follows an elliptical orbit not a circular one.

Like any full moon, tomorrow’s moon will look bigger when it’s on or near the horizon rather than higher in the sky, thanks to an optical illusion. The full moon appears on the horizon at sunset. On the East coast, for example, that will be a at 5.07pm.

The last “supermoon” on March 20, last year was about 380 km closer than this year’s will be. Next year’s will be even a bit farther away than this year’s. Each year there is a perigee and an apogee Moon and the distances vary.

One effect that can be noticed doesn’t affect me where I live, but coastal folks are very familiar with the tides and how their height varies over the course of a month, again, due to the Moon not always being the same distance from the Earth. As the Moon’s orbit brings it in closer proximity to our planet, its gravitational forces can increase by almost 50%, and this stronger force leads to high tides. Likewise, when the Moon is farther away from the Earth the tides are far less spectacular.

The Moon’s influence can also be balanced out by the position of the Sun – if the Sun and the Moon find themselves 90 degrees apart in relation to an observer on the Earth, then high tides are not as high as they normally would be. This is because despite its greater distance from the planet, the Sun’s mass allows it to exert enough gravitational force on the oceans that it can negate some of the effects of the Moon’s pull. This phenomenon of lower high tides is called a neap tide. In the same way, when the Sun lines up with the Moon and the Earth, as during a Full Moon, then the Sun can act to amplify the tidal forces, drawing even higher tides. These are known as spring tides, named not for the season, but for the fact that the water “springs” higher than normal. The variance in the height of the world’s tides also depends on the local geography of the coastline and the topography of the ocean floor.

Created in Stellarium - finder for the eta aquarids

are usually a lightish meteor shower producing about 10 meteors per hour at their peak in the Northern Hemisphere but can peak at around 40-50 per hour here in the Southern hemisphere in a dark sky. The shower’s peak usually occurs on May 5 & 6, however this shower tends to have a broad maximum so viewing should be good on any morning from May 4 – 7.

The full moon which occurs on May 6th will probably ruin the show this year, washing out all but the brightest meteors with its glare.

But still worth having a look if you are up, to see how many Eta Aquarids can be seen in the moonlit sky. For the most part, this is a pre dawn shower. The radiant for this shower appears in the east-south-east at about 4 a.m. local time (wherever you are) and the hour or two before dawn usually offers the most meteors.

Apple and Android Device Owners Get Special Pricing on Award-
Winning Astronomy Apps While Supporting Astronomers Without
Borders’ Global Astronomy Programs April 16, 2012.

For the last two weeks of Global Astronomy Month
2012 (GAM 2012), April 16 to 30, Southern Stars’ very popular
SkySafari 3 apps for Apple and Android mobile devices and Mac OS
X are available at discounted pricing.
During this special GAM 2012 promotion, 30% of proceeds from all
SkySafari sales will be donated to Astronomers Without Borders
to support Global Astronomy Month and other Astronomers Without
Borders global programs.
Astronomers Without Borders endorsed the award-winning SkySafari
as its preferred mobile astronomy app in 2011, and recommends its use
for all Global Astronomy Month activities.

more info:

• SkySafari 3 – $2.99, 48 MB. 46K stars, no telescope control.

  The basic version of SkySafari 3 shows you 46,000 stars, plus 220 of the best-known star clusters, nebulae, and galaxies in the sky. It displays the Solar System’s major planets and moons using NASA spacecraft imagery, and includes the best-known 150 (or so) asteroids, comets, and satellites.

• SkySafari 3 Plus – $14.99, 181 MB, 2.5M stars, telescope control.

  SkySafari 3 Plus adds a hugely expanded database – and wired or wireless telescope control – to our basic version. It shows you 2.5 million stars, and 31,000 deep sky objects – including the entire NGC/IC catalog. It includes over 4,000 asteroids, comets, and satellites with updateable orbits. And it can point your GoTo or “Push-To” telescope anywhere in the sky, using your iPhone/iPad/iPod’s built-in WiFi, and our SkyFi or SkyWire serial accessories.

• SkySafari 3 Pro – $59.99, 418 MB, 15M stars, telescope control.

  The all-new SkySafari 3 Pro has the largest database of any astronomy app, period. It contains everything in SkySafari 3 Plus – but also includes over 15.3 million stars from the Hubble Guide Star catalog, plus 740,000 galaxies down to 18th magnitude, and over 550,000 solar system objects – including every comet and asteroid ever discovered. Yet it runs just as fast and smoothly as our $3 basic version.

check it out for yourself

http://www.southernstars.com/products/skysafari/index.html

WASHINGTON — A new NASA outreach project will enlist the help of
amateur astronomers to discover near-Earth objects (NEOs) and study
their characteristics. NEOs are asteroids with orbits that
occasionally bring them close to the Earth.

Starting today, a new citizen science project called “Target
Asteroids!” will support NASA’s Origins Spectral Interpretation
Resource Identification Security – Regolith Explorer (OSIRIS-REx)
mission objectives to improve basic scientific understanding of NEOs.
OSIRIS-Rex is scheduled for launch in 2016 and will study material
from an asteroid.

Amateur astronomers will help better characterize the population of
NEOs, including their position, motion, rotation and changes in the
intensity of light they emit. Professional astronomers will use this
information to refine theoretical models of asteroids, improving
their understanding about asteroids similar to the one OSIRIS-Rex
will encounter in 2019, designated 1999 RQ36.

OSIRIS-Rex will map the asteroid’s global properties, measure
non-gravitational forces and provide observations that can be
compared with data obtained by telescope observations from Earth. In
2023, OSIRIS-REx will return back to Earth at least 2.11 ounces (60
grams) of surface material from the asteroid.

Target Asteroids! data will be useful for comparisons with actual
mission data. The project team plans to expand participants in 2014
to students and teachers.

“Although few amateur astronomers have the capability to observe 1999
RQ36 itself, they do have the capability to observe other targets,”
said Jason Dworkin, OSIRIS-REx project scientist at NASA’s Goddard
Space Flight Center in Greenbelt, Md.

Previous observations indicate 1999 RQ36 is made of primitive
materials. OSIRIS-REx will supply a wealth of information about the
asteroid’s composition and structure. Data also will provide new
insights into the nature of the early solar system and its evolution,
orbits of NEOs and their impact risks, and the building blocks that
led to life on Earth.

Amateur astronomers long have provided NEO tracking observations in
support of NASA’s NEO Observation Program. A better understanding of
NEOs is a critically important precursor in the selection and
targeting of future asteroid missions.

“For well over 10 years, amateurs have been important contributors in
the refinement of orbits for newly discovered near-Earth objects,”
said Edward Beshore, deputy principal investigator for the OSIRIS-REx
mission at the University of Arizona in Tucson.

NASA’s Goddard Space Flight Center in Greenbelt, Md., will provide
overall mission management, systems engineering and safety and
mission assurance for OSIRIS-REx. Dante Lauretta is the mission’s
principal investigator at the University of Arizona. Lockheed Martin
Space Systems in Denver will build the spacecraft. OSIRIS-REx is the
third mission in NASA’s New Frontiers Program. NASA’s Marshall Space
Flight Center in Huntsville, Ala., manages New Frontiers for the
agency’s Science Mission Directorate in Washington.

For more information about NASA, visit:

http://www.nasa.gov

For more information on Target Asteroids! and OSIRIS-REx, visit:

http://osiris-rex.lpl.arizona.edu

The Story:
The Great Melbourne Telescope is one of the great hidden stories of 19th century Melbourne, yet at the time it received much press coverage and public attention. At the completion of its construction by Dublin engineer Thomas Grubb, the telescope was hailed as a masterpiece of engineering, the first large telescope to be placed on an equatorial
mounting. Erected at Melbourne Observatory in 1869, the telescope was the second largest telescope in the world, designed to explore the nature of the nebulae in the southern hemisphere skies.

The telescope was transferred to Mount Stromlo Observatory in 1946, where it was twice rebuilt and modernised for major research projects, until it was destroyed by the 2003 Canberra bushfires.

The Great Melbourne Telescope is about to embark on a new chapter in its history, with plans to restore and refurbish it for public and educational use, back home in its original building at Melbourne Observatory.

About the Speaker:
Dr Richard Gillespie trained as a historian of science at the University of Melbourne and University of Pennsylvania. He taught history of science and medicine at the University of Pennsylvania, Deakin University and the University of Melbourne before joining Museum Victoria in 1990, where he is now Head of the History & Technology Department. The department cares for a collection of close to one million objects, images and related archives. The department also contributes to exhibitions, websites, publications and programs, and provides historical expertise for the interpretation of three heritage buildings: the World Heritage listed Royal Exhibition Building, the old Melbourne Customs
House, and the Spotswood Sewerage Pumping Station. Richard Gillespie has also led the development of exhibitions at Melbourne Museum, Scienceworks and the Immigration Museum He has been a Fulbright Scholar, been awarded a Mellon Fellowship,
Gordon Darling Fellowship, and received the Henry Schuman Prize of the History of Science Society (US).

He is the author of The Great Melbourne Telescope (Museum Victoria, 2011) and Manufacturing Knowledge: A History of the Hawthorne Experiments (Cambridge Univ
Press, 1987).

Registration at:  http://www.engineersaustralia.org.au/divisions/victoria-division/events is
preferred.
This is a free event.
Contact for queries: Emily James at:
ejames@engineersaustralia,org.au
Attendance may be credited towards Engineers