astronomy

Molonglo Observatory Synthesis Telescope

Molonglo Observatory Synthesis Telescope is a astronomy topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Molonglo Observatory Synthesis Telescope rather than just read about it. In short: The Molonglo Observatory Synthesis Telescope (MOST) is a radio telescope operating at 843 MHz. It was operated by the School of Physics of the University of Sydney.

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Reference excerpt

The Molonglo Observatory Synthesis Telescope (MOST) is a radio telescope operating at 843 MHz. It was operated by the School of Physics of the University of Sydney. The telescope is located in Hoskinstown, near the Molonglo River and Canberra, and was constructed by modification of the east–west arm of the former Molonglo Cross Telescope, a larger version of the Mills Cross Telescope. Construction of the original "Super Cross" telescope with 1.6-kilometre arms began in 1960 by Professor Bernard Y. Mills. It became operational in 1967.

Design The MOST consists of two cylindrical paraboloids, 778m x 12m, separated by 15m and aligned east–west. A line feed system of 7744 circular dipoles collects the signal and feeds 176 preamplifiers and 88 IF amplifiers. The telescope is steered by mechanical rotation of the cylindrical paraboloids about their long axis, and by phasing the feed elements along the arms. The feed elements were decommissioned in 2018 so that the telescope began to operate in transit mode only. Prior to this, the `alt-alt' system could follow a field for ± 6 hours (necessary for a complete aperture synthesis with an east–west array) for fields south of declination -30 degrees. For fields near this limit the signal-to-noise ratio is lower for the first and last hour or so due to the lower gain of the system at large 'meridian arc distance' angles.

The Molonglo Cross Telescope was a 408 MHz radio telescope built by Bernard Y. Mills and collaborators and operated by the University of Sydney. It telescope consisted of a north–south arm and an east–west arm in a cross shape. Each arm was approximately one mile in length. The east–west arm was split into 88 individual elements to form the current Molonglo Observatory Synthesis Telescope.

Grote Reber

The design of the original system owes much to pioneering radio astronomy by Grote Reber in the US and Australia, that informed Mills' work. A memorial to Reber, including some of his ashes, is sited at the telescope.

MOST work Much pioneering radio astronomy was done with this telescope. The Molonglo Cross Telescope was used for a survey of the Southern sky with a resolution of 2.8 arc-min. The telescope's main research project was the Sydney University Molonglo Sky Survey (SUMSS), a sensitive radio imaging survey of the southern sky at 843 MHz with similar resolution and sensitivity to the northern NRAO VLA Sky Survey (NVSS). SUMSS is now complete, and digital images and a source catalogue are available online. After a five-year break in which analog equipment was upgraded the observatory is now used to detect fast radio bursts and do research on pulsars. The equipment for fast radio burst detection is called UTMOST.

Square Kilometre Array development MOST is being used to develop technology for the Australian site of the Square Kilometre Array telescope. Since 2003 work has proceeded on the SKA Molonglo Prototype (SKAMP) which has included fitting new wide-band feeds, low-noise amplifiers, digital filterbanks and correlator, in order to demonstrate 300-1420 MHz continuous frequency coverage and multibeam mode operation. The new correlator is a 96 input continuum correlator using Field Programmable Gate Array (FPGA) chips. This effort is a collaboration between the Australia Telescope National Facility (ATNF), the Australian Commonwealth Scientific and Industrial Research Organisation (CSIRO) Information and Communications Technology Centre, and the University of Sydney.

UTMOST Since 2015, the telescope has been operated in a collaboration between the University of Sydney and Swinburne University of Technology. The goal is to probe the radio transient sky in real time, monitoring pulsars and magnetars, and searching for Fast Radio Bursts. The telescope sensitivity was improved by a refit of receiver technologies on one of its arms (in the east–west direction), and presently (late 2020) the north–south arm is being fitted out with significantly improved receivers as well. This will allow Fast Radio Bursts and similar radio transients to be located on the sky with a few arcseconds of precision, sufficient to identify the host galaxies from which the originate.

See also List of astronomical observatories Lists of telescopes

Notes

References "The Molonglo Observatory Synthesis Telescope (MOST)". Sydney Institute for Astronomy. University of Sydney. 2009. Archived from the original on 25 July 2012. Retrieved 13 June 2009.

External links Media related to Molonglo Observatory Synthesis Telescope at Wikimedia Commons

Illustrations

Worked examples

Example 1 — a first encounter with Molonglo Observatory Synthesis Telescope

Start with the simplest possible case. Write down what Molonglo Observatory Synthesis Telescope claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In astronomy, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Molonglo Observatory Synthesis Telescope before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Molonglo Observatory Synthesis Telescope ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Molonglo Observatory Synthesis Telescope

In research: Molonglo Observatory Synthesis Telescope appears in astronomy research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Molonglo Observatory Synthesis Telescope in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Molonglo Observatory Synthesis Telescope is common in secondary-school and first-year university syllabi. It links to neighbouring topics Astronomical observatories in New South Wales, Interferometric telescopes, Radio telescopes, so understanding it makes those chapters shorter.
In everyday life: Look for Molonglo Observatory Synthesis Telescope outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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Frequently asked questions

What is Molonglo Observatory Synthesis Telescope in simple terms?

The Molonglo Observatory Synthesis Telescope (MOST) is a radio telescope operating at 843 MHz. It was operated by the School of Physics of the University of Sydney.

Why does Molonglo Observatory Synthesis Telescope matter?

Because it connects several astronomy ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Molonglo Observatory Synthesis Telescope?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Molonglo Observatory Synthesis Telescope.