Astronomers at the SAAO and the Massachusetts Institute of Technology (MIT), USA have recently detected what may be rings around Chiron, a minor planet in our solar system. Though it is well-known that all the gas giant planets have rings, the minor planet Chariklo also has them. Chiron and Chariklo belong to a class of minor planets called centaurs: small rocky bodies that possess properties of both asteroids and comets and are found in a band between the orbits of Jupiter and Pluto. Prior to the discovery of Chariklo's rings, centaurs were thought to be relatively dormant objects. The latest discovery of a possible ring system around another centaur, Chiron, if confirmed, suggests that ring systems are far more common in our solar system than previously thought.
Dr A. Kniazev from the South African Astronomical Observatory (SAAO), and collaborators from the Lomonosov Moscow State University Dr. V. Gvaramadze and Dr. L. Berdnikov have recently discovered a new example of an incredibly rare kind of star known as a Luminous Blue Variable (LBV). Out of the billions of stars mapped in our skies, only sixteen confirmed LBVs are known to date. The star, named WS1, is the latest addition to this group. LBV stars are of interest because they are extremely old and may soon die and blow apart as supernovas.
In the early hours of the 7th April, an unmanned robotic telescope, MASTER-SAAO, situated near Sutherland in the Karoo, discovered a new comet (see front cover of this issue) . This is the first comet to be discovered in South Africa since 1978. The Russian - South African run telescope has been scanning the southern skies since it began operating in late December 2014, looking for "transients" - new objects which appear in the sky for the first time. Since then, over 60 new objects have been discovered, most of them being erupting or exploding stars. Now the MASTER-SAAO telescope has just discovered its first comet.
On April 24, 1990, the space shuttle Discovery lifted off from Earth with the Hubble Space Telescope nestled securely in its bay. The following day, Hubble was released into space, ready to peer into the vast unknown.
Planetary astronomers, including the SA Astronomical Observatory's Head of Instrumentation, Dr Amanda Gulbis, have been investigating Pluto's atmospheric properties and evolution by observing stellar occultations by the planet, and using multiple telescopes in the United States (2012) and Chile (2013). Their results appeared in January this year in journal Icarus, under Bosh et al. (2015) and Gulbis et al. (2015). A special issue of the journal was dedicated to the current understanding of the Pluto System on the eve of the arrival of New Horizons at Pluto.
The effect of the number of dark frames subtracted from a light frame on the signal to-noise ratio (SNR) of stars is investigated. The conclusion is that applying a single dark frame gives a substantial improvement in the SNR of stars, while applying additional dark frames gives only a very small improvement.
This article covers the activities of the various MOONWATCH teams in the Durban area. In particular those of Arthur Arnold and Greg Roberts. Because some duplication has been eliminated, please read this account in conjunction with Part 2. The MOONWATCH organization was not interested in observations from amateurs unless associated with a recognized MOONWATCH site so this excluded many from participating in tracking satellites so, as detailed in Part 2 of this series, other organizations came into being up that offered some scope for amateur satellite enthusiasts to make meaningful contributions to the space program. Roberts in mid-1957 volunteered to set up a MOONWATCH station before the first satellites were launched but his offer was declined because of the anti "lone wolf" policy, so initially tracking activities where not MOONWATCH orientated.
We are lucky to have a great starry Ark sailing in the southern skies to please our eyes just before winter throws its blanket over us. Puppis and some other constellations were previously lumped together as the constellation Argo Navis. The Germans called Navis the Schiff, the French Navire Argo and the Italians Nave Argo. The ship's four divisions are now known as Carina the Keel, Puppis the Stern, Vela the Sail and the Mariner's Compass Pyxis. From the Bible's reference to Noah's Ark, it was popularly known in the 17th century as the Ark. It was the French astronomer Nicolas Louis de Lacaille who divided up this monster ship in the 18thcentury.