Like most museums the Powerhouse collection is larger than we could possibly display. The Powerhouse Discovery Centre (PDC) at Castle Hill contains shelves full of historical ‘treasure’ – and this includes clocks & telescopes once used at Sydney Observatory.

On Saturday February 11, the PDC holds its first Open Day for the year and I will be conducting a ‘Behind the Scenes’ tour of H-store to show off some of our most significant clocks and telescopes. Highlights will include Governor Brisbane’s Hardy ‘regulator’ clock of 1808,  George the Speaking Clock and the ultra-precise Rubidium atomic clock that disseminated time from the Observatory until the 1980s. Telescopes include the 13-inch Melbourne astrograph used to make the first photographic map of the sky and the long-lost “horseshoe” style telescope mount, invented by our very own Henry Russell in 1878 and now used for Australia’s largest telescope – the Anglo-Australian Telescope.

There are many other activities to get involved in for young and old: A Chinese Water Dragon, ‘Rocket Science’ and the Peppin Merino amongst others. Find out all the details and how to book on the Open Day flyer.

Please note this event is NOT being held at Sydney Observatory and, while the day is open to all,  you must be 12+ years old to join my ‘Time & Telescopes’ tour.

An Australian Post Office film about the arrival of the first automatic speaking clocks in Sydney and Melbourne in 1954. Thank you to vk3ase for finding and posting this film on YouTube

Today everything is small and electronic. Our watches with their quartz crystals keep the time to a few seconds a day and we can obtain the time to even greater accuracy using smart phones. These devices provide convenience and functionality, but we have lost the wonderful and complex ingenuity of the past. Mechanical watches with their escapements and moving balance wheels were treasured items of beautiful intricacy. Unlike the situation today, with a little application their workings could be understood and admired.

The time provided on the telephone by ringing 1194 is today all electronic, although wonderfully it appears to be the same voice as back in 1954. As shown in the video above, that year saw the arrival and installation of the automatic Speaking Clock, affectionally known as George, in Australia’s two main cities, Sydney and Melbourne . This clock was a marvel of engineering that synthetised the time from three different optical discs. Sound tracks were recorded like in movie films as brightness fluctions on the discs. In use the discs were ‘read’ by using photoelectric cells that converted the brightness variations to voltage fluctuations. Australian actor Gordon Gow recorded the sound on the discs.

The speaking clock being serviced. Courtesy Powerhouse Museum

The Sydney clocks were housed in the GPO in Martin Place; there were two – one operating and the other serving as backup. When they were retired and replaced in 1990, one of them came to the Powerhouse Museum after restoration by a technician in his spare time. For a number of years George the Speaking Clock was on display at Sydney Observatory as an interactive exhibit. Visitors could press buttons to hear the fully synthetised time or only part of the sound track.

The door of the speaking clock room at the old GPO in Martin Place is also part of the Museum’s collection. Courtesy Powerhouse Museum

George is now carefully stored at the Powerhouse Discovery Centre at Castle Hill and is shown occasionally on open days. Hopefully, in a few years, there will be suitable exhibition at the Museum and visitors once again will be able to admire the clock’s wonderful ingenuity.

Toner Stevenson, Manager Sydney Observatory, reports from Western Australia.

My recent visit to Perth included visiting the Observatory at Bickley. Not only was I treated to a fabulous lunch prepared by and shared with all the observatory staff, there was the opportunity to go behind the scenes with acting Director, Ralph Martin, astronomer Dr. Andrew Williams and education manager Greg Lowe.

Perth Observatory, the 1896 foundation stone is on the lower right side. Photo T. Stevenson, 2011

On approach up the long driveway that separates Perth Observatory from Bickley’s suburban sprawl the first thing I noticed was the foundation stone dated 1896 in front of a clearly 1960s modernist building. This stone, laid by John Forrest, marks the first Perth Observatory building established in Kings Park, close to what is now the city.  Like Sydney Observatory during the late 1800s, the observatory was the colonial centre for astronomy, timekeeping, meteorology and surveying, covering the vast state of WA.  Over time these functions were mostly removed or reduced significantly, and in 1965 Perth Observatory was relocated to the suburb of Bickley, about 40 minutes outside Perth.  Fortunately more than the original foundation stone was relocated from the city site as I soon discovered.  Many significant items of a past era shared with Sydney Observatory have been carefully kept and some were still in use.  From the minute I stepped through the door I sensed the strong ties between Perth and Sydney Observatories re-connecting, it felt like catching up with a dear friend. 

William Earnest Cooke (seated left) Director of Perth Observatory, pictured with Yeates, Curlewis, Ackland and Jocelyne in front of Old Perth Observatory, 1901. Courtesy Perth Observatory Collection.

The astronomer and meteorologist William Earnest Cooke was the first Western Australian Government astronomer (1896 to 1912) and in 1912 he accepted the Directorship of Sydney Observatory.  It was through Cooke’s initiatives that in 1900 Perth Observatory undertook work on the Astrographic Catalogue and Carte du Ciel.  Both Sydney and Melbourne observatories had already begun work on this ambitious international project to catalogue and chart the entire sky. Like Sydney, Perth Observatory has an active public day and night tour program , publishes an annual astronomy almanac and supports its heritage work through an adopt a star program, drawing on its own catalogue of stars also providing recipients the opportunity to view their star. 

Perth’s astrographic telescope by renowned Irish instrument maker Howard Grubb is in impressive working order and Greg Lowe showed me how this is demonstrated as part of the regular night tour.  Designed to photograph the stars, this telescope was the standard chosen for use by the British Observatories participating in the Astrographic Catalogue.  Sydney Observatory’s ‘star camera’, a unique telescope design by Henry Chamberlain Russell, had only the lens supplied by Grubb. But the Melbourne Astrographic telescope, moved to Sydney Observatory in 1948, appears almost identical to the one in Perth. These instruments are in the Castle-Hill store pending conservation. The original Perth Astrographic dome was removed from the 1896 building and relocated to Bickley. It is one of a number of telescope domes, some of which are made accessible to the public. This restored 1910 Calver (Newtonian) telescope can be compared to the view through the contemporary 40cm MEADE Schmidt Cassegrain.

Acting Director, Ralph Martin with the 1910 Calver (Newtonian) telescope used during night tours. Photo T. Stevenson, 2011

This site is a living astronomy archive with a comprehensive astronomy library, extensive glass plate negative collection, heritage instruments and a complete set of Astrographic Catalogues.  An exhibition displays some of the treasures from their collection and is well worth a visit. At night you can experience the night sky from a relatively dark sky environment through telescopes. 

Perth Observatory is the only State-run Observatory still equipped and staffed for research and as such the public are also able to witness science in action.  High up on a 15metre tower is the primary research telescope and largest dome on the site. The Perth-Lowell automated telescope is operated remotely and has a sensor that closes the dome in wet weather. Ralph Martin spoke about the partnerships Perth Observatory has formed with Universities, major projects such as ICRAR (International Centre for Radio Astronomy Research)  and Perth Observatory’s gravitational micro-lensing work which has led to the discovery of smaller planets rotating around distant stars. You can take a virtual tour of the Perth-Lowell observatory without climbing all the stairs.  

Astronomer Dr. Andrew Williams with the Perth-Lowell telescope. Photo T. Stevenson.

I also visited the Old Perth Observatory, a grand residence for the Government Astronomer. With 2012 the centenary of W.E. Cooke’s departure from Perth to the Directorship of Sydney Observatory expect other blogs to follow throughout the year.

To help you learn about the southern night sky, Sydney Observatory provides an audio guide/podcast, transcript of that audio, and a sky map or chart each month. This month’s guide is presented by Melissa Hulbert, an Astronomy Educator at Sydney Observatory.

Mel provides fascinating insights into the February night sky, with her tour including the constellations Orion, Taurus, Canis Major and the former constellation of Argo Narvis (the Ship of the Argonauts) – which has since been broken up into three smaller constellations, each being a part of the ship: Carina (the keel), Vela (the sails) and Puppis (the poop).

Planets to look out for this month are Venus, Jupiter, Mars and Saturn – with the Moon close to Venus and Jupiter after sunset from 25 to 28 February, making a striking trio in our western sky.

Listen to the audio, or read the transcript below for more details.

HEAR THE AUDIO
You can subscribe with iTunes or upload the audio to your iPod or mp3 player, or listen to it on your computer.

SEE THE SKY CHART
We provide an embedded sky map (below) and a February 2012 night sky chart (PDF) which shows the stars, constellations and planets visible in the night sky from anywhere in Australia. To view PDF star charts you will need to download and install Adobe Acrobat Reader if it’s not on your computer already.

BUY THE BOOK
Our annual book, ‘The 2012 Australasian sky guide’, by Dr Nick Lomb has more information and star maps for months from December 2011 until December 2012 inclusive, plus information about the Sun, twilight, the Moon and tides, and a host of other fascinating astronomical information. You can purchase it ($16.95) at Sydney Observatory and Powerhouse Museum shops or other good bookshops, or online through Powerhouse Publishing (additional packing/postage costs apply).

READ THE TRANSCRIPT (after the jump)

(more…)

HC Russell’s observations at the end of the transit as seen from Sydney Observatory. Photo lithograph from Observations of the Transit of Venus, 9 December, 1874. Powerhouse Museum Research Library

In the previous post I considered the preparations of Henry Chamberlain Russell, the director of Sydney Observatory, for the 1874 transit and the magnificent illustrated book that he published on the event. Here I show a couple of the illustrations from the book.

Russell observed with the new 29-cm or 11½-inch refractor or lens telescope from Hugo Schroeder of Hamburg, Germany. To reduce the heat from the Sun he used an aperture to reduce the main lens to 5 inches (12.5 cm) in width and coloured glass filters in front of and behind the eyepiece. From Sydney the transit began just before local noon and within a few minutes he could see the aureole on the part of the planet still outside the disc of the Sun. He described what he could see as, ‘It was very remarkable and beautiful, like a fringe of green light, through which the faintest tinge of red could be seen’. Since Russell was looking through coloured filters the colours that he describes may not be real.

Four hours later Venus was again at the edge of the Sun prior to egress. In his illustration of the egress Russell presents a sequence of five images with time increasing to the left. Though Russell emphasises that he did not see ‘the black drop’, in the first drawing of the sequence, made just after internal contact, we can see some haziness that is clearly due to similar or the same atmospheric effects as the black drop. Two minutes later the aureole that he called the ‘halo’ was clearly visible on the part of Venus off the Sun. Another 15 minutes later he says, ‘the halo was for the first time seen irregular–in diameter it seemed considerably broader at the north pole of the planet as shown’. For the last few minutes before the planet completely left the Sun, Russell was struggling with poor definition due to approaching clouds, but a white patch could be seen near the north pole of the planet.

Amateur astronomer Mr Alfred Fairfax’s drawing of the aureole through a 4¾-inch (12-cm) lens telescope. The scale of the aureole is greatly exaggerated to allow details to be shown. Photo lithograph from Observations of the Transit of Venus, 9 December, 1874. Powerhouse Museum Research Library

The aureole is due to sunlight refracted through the atmosphere of Venus, but why was there a brightening near the pole of the planet? This went unexplained for 130 years until the 2004 transit. In an article in the Astronomical Journal (141:112 (9pp), 2011 April) Jay M. Pasachoff, Glenn Schneider, and Thomas Widemann indicate that they saw the same effect with the TRACE spacecraft, this time with a brightening near Venus’ south pole. They explain their observations and those of Russell by appealing to previous spacecraft observations of the structure of the planet’s atmosphere. The observations indicate a ring or torus of cold air surrounding each of the poles of the planet that lower the average cloud top height by about 10 km. Extra sunlight can thus stream through regions surrounding the poles of the planet to create the polar spots.

Russell would have been thrilled to have his observations explained. Maybe the 2012 transit will lead to an explanation of those by Mr Fairfax!

This blog post is simultaneously published on the Transit of Venus website

The dome of the 46-cm (18-inch) telescope at Mt Burnett Observatory. Image and copyright Nick Lomb ©, all rights reserved

On Saturday evening 21 January 2012 I found myself at the opening of Mt Burnett Observatory as a public and amateur observatory. The location is about 40 km east of Melbourne and is a relatively easy drive of about one hour from at least some areas of the city. The observatory will hold regular viewing nights and encourages members of the local community as well as those interested from Melbourne to join.

The Physics Department at Monash University operated Mt Burnett as a field station from the 1970s. Originally the main instrument was a 40-cm (16-inch) reflector that was replaced in 1985 by a slightly larger and more modern telescope with a 46-cm (18-inch mirror). The telescope was largely used for photoelectric observations of the brightness variations of short-period stars in the southern sky. One of the people at Saturday evening’s opening was Dr Len Halprin who was the first student from Monash to complete a PhD (in 1983) using observations at the site.

The 46-cm (18-inch) telescope at Mt Burnett Observatory is on a solid equatorial mounting. Image and copyright Nick Lomb ©, all rights reserved

As a detailed history of the Monash years is available here.I will not discuss more of the site’s history except to mention the person who would be the best known in the amateur community. David Herald made the first observations with the original 40-cm telescope before it was taken to Mt Burnett as part of his Honours year in 1971. Afterwards he joined the Patent Office in Canberra and reached a senior position there. He has, however, maintained his interest in astronomy and has produced extensive and distinguished work as an amateur astronomer.

As the observatory no longer fits the needs of Monash University or its students, the university was keen to transfer the observatory to another organisation. It has now been taken over by a group of amateur astronomers led by high-profile amateur Perry Vlahos, who, among many other activities, writes a regular column in the Thursday editions of The Age newspaper.

Perry Vlahos entertaining the crowd at the launch of the rejuvenated Mt Burnett Observatory. Image and copyright Nick Lomb ©, all rights reserved

The opening festivities began with tours of the telescope, a sausage sizzle and then Perry introduced the committee members working to rejuvenate the observatory to the audience, which was a mix of local people and invited guests. Afterwards as the sky was cloudy Perry gave an introductory talk on astronomy.

Late in the evening the clouds began to dissipate and Venus, Jupiter and the stars began to be visible. The sky at Mt Burnett is not the darkest that I have seen, but compared to what can be seen from suburban Melbourne or Sydney, it is a revelation. It was dark enough to clearly see the Large Magellanic Cloud though the smaller cloud being lower in the sky was somewhat harder to discern. There were a number of people operating small telescopes and through their telescopes I had the pleasure of glimpsing Jupiter with its Galilean moons, the Great Nebula in Orion and the wonderful globular cluster 47 Tucanae. I also saw a bright meteor streak across the sky in the vicinity of the Southern Cross.

What I enjoyed most though is the banter in the darkness between the amateur astronomers with telescopes as numerous satellites criss-crossed the night sky. ‘Satellite in Canis Major’, yells out one and everyone within earshot looked and tried to pick it out. Soon from another direction there was, ‘Satellite in Orion, just below Rigel and now it has just taken out Alnilam [the middle star of Orion’s belt]!’.

For the small group who has taken on the task, it will be hard work upgrading and maintaining the observatory as well as running public viewing nights. For more information or for anyone in the vicinity who would like to become a member, Mt Burnett Observatory has a website. I wish the observatory and its participants good viewing and clear skies!

Les Dalrymple in his native environment observing with his 18” Newtonian near Parkes in 2010 on a cold and frosty evening.

Globular Clusters: observed and presented by Les Dalrymple
A Sydney City Skywatchers presentation
Monday 6 February
6:30pm – 8:30pm
Les Dalrymple has been an amateur astronomer and avid visual observer for more than forty years. He has one of the largest observing logs in the world containing notes and sketches pertaining to more than 5,000 objects in the night sky. Les has made his own telescopes and joined Sutherland Astronomical Society Inc when he was 11. Les has been a contributing editor for Sky & Telescope magazine since 2001 as a contributing editor and from 2005 he has been involved with the Australian version of that magazine – Australian Sky & Telescope as a founding contributor with over 100 articles published in Australian Sky & Telescope during its seven year history.

Les has been involved in public astronomy widely for more than thirty years, and is a long-standing night astronomy guide at Sydney Observatory. He has been an invited speaker at many of the leading astronomical gatherings in NSW.

This presentation promises to be exciting and real opportunity to engage with one of Australia’s most knowledgeable and active visual astronomers. The evening also includes interesting illustrated reports from other observers.

Cost: $2 door charge (includes supper). Open to Members and everyone who is passionate about astronomy. It is possible to join Sydney City Skywatchers on the evening or take home a membership form.

Sydney City Skywatchers – an astronomy group for locals
6:30pm, first Monday of the month
in Sydney Observatory’s basement Discovery Room
Join the oldest operating astronomical group in Sydney. The group provides an opportunity for those interested in astronomy to share and broaden their interest in the sky. People at all levels are catered for from beginners to serious amateur astronomers. Whether you want to just listen to a monthly lecture or to discuss serious observing through a telescope, this is the club for you.

These meetings usually consist of brief reports of observations made during the month by club members and a presentation from a guest speaker followed by a light supper. There is a $2 fee for each meeting.

The main Australian observing stations for 1874 transit of Venus. Sketch Nick Lomb

Like the June 2012 transit of Venus, the December 1874 transit was visible in its entirety from Australia. The observatories at Sydney, Melbourne and Adelaide, which are the capitals of the three main states or colonies at the time, made plans to ensure that the rare event was well observed. In addition, there were two United States observing teams in the island state of Tasmania.

In subsequent posts I will discuss the plans and activities at the different places. Here I would like to introduce you to the magnificent book published by Henry Chamberlain Russell, the director of Sydney Observatory, about the 1874 transit observations in 1892. Images from this book are used in almost every book or article published in recent times on the transit. Disappointingly, the images are often not credited or wrongly credited to Charles Potter, the Government Printer, whose name is prominently on the front cover of the book.

In preparation for the transit Russell obtained new instruments including a 29-cm or 11½ -inch refractor or lens telescope from Hugo Schroeder of Hamburg, Germany that is still one of the treasures of Sydney Observatory. He also arranged for three observing stations at country sites to maximise the possibility of obtaining observations if the weather was poor. To staff these extra stations he recruited best scientific men in the Colony including Archibald Liversidge, the newly arrived professor of geology at the local university.

The cover of Henry Chamberlain Russell’s book on the 1874 transit of Venus. Courtesy Powerhouse Museum Library

Immediately after the transit Russell requested all the observers to submit written reports as well as illustrations of their observations. He intended to publish these results as soon as practicable, writing to the Under Secretary of Finance and Trade on 30 January 1875:

The results obtained in New South Wales during the recent Transit of Venus are of the greatest importance, both in a scientific point of view, and also with regard to the credit due to this Colony for the position taken in this important scientific matter.

In order to make the results generally known they must be printed in a first class style, reproducing in the book all drawings photographs &c so far as possible. If this is properly done the work will become known all over the scientific world, and great credit will accrue to this Colony.

Russell goes on to explain that his absence overseas (to report in person to the Astronomer Royal at Greenwich) would not cause undue delay as, in any case, the lithographs would take six months to produce. In the event it took 18 years for the book to be published. Why the long delay? I think that it was the fault of the Government Printer and the manuscript had languished with the printer for most of the 18 years. When I found the originals of the book and its illustrations in the Observatory archives there was a note with them from Russell saying to the printer that the book has been delayed for long enough and to please get on with publishing it.

In the next post we will look at a few of the illustrations from the book and discuss why recently they have been found to provide useful information about the atmosphere of Venus. We will also consider the controversy surrounding the contents of the book.

This blog post is simultaneously published on the Transit of Venus website

A sketch of the four components of Gamma Velorum that can be seen through a small telescope. Image and copyright Harry Roberts ©, all rights reserved

We often take common objects for granted – despite some being truly unique. Sometimes it helps to remember their exotic nature -such a star is Gamma Velorum.

Sited at 47º south declination – it’s in our night sky most of the year, and highest in summer. Only when searching the naked eye stars for O types did I find that it is the brightest O type AND (by far) the brightest Wolf-Rayet type in the whole sky. As such it is of interest to northern viewers whose brightest O and WR types are very much fainter.

At magnitude 1.7 Gamma Vel. is a bright star, and in almost any amateur ‘scope it is a multiple – four components are seen in a small refractor at 60X. All are part of the same system – not line-of-sight members. They comprise the primary A, aka Gamma 2 Velorum, with the others B, C and D. The sketch (Fig1) shows the view through a small scope – and there are some colour contrasts worth noting.

The colour of primary A is hard to explain – I’ve always seen it as violet maybe, but often with a green tint. When David Malin published “Colours of the Stars” he noted there were no green stars. And due to the physics of black bodies – I’m sure he’s right. Except to say that this particular star emits so much yellow and blue light in its carbon emission bands, as well as strong green and violet continua, that we have, with Gamma2 perhaps, an exception to the “no-green” rule.

Star B by contrast is a normal B type, of 4.2 magnitude – and looks blue in a range of scopes. Stars C and D are white, as they are type A stars, of 8 and 9 magnitude.

Historic accounts of colour in doubles were made with older refractors that often had strong false-colour – modern reflectors or “cats” show more accurate colours. What colour do you see?

Most southern viewers know the star group dubbed the “False Cross”, like a lop-sided version of the Southern Cross, This handy grouping blends stars from constellations Carina (“the keel”) and Vela (“the sails”) of ancient Argo Navis. A projection of the short arm of the false cross westward leads to Gamma Velorum. It is worth a look with almost any scope.

It is true that the southern sky lacks the common names of the north – and there have been attempts to remedy this. Gamma Velorum is quite a mouthful – and the ancient Arabic name “Suhail” has not caught-on, and is used for other stars in the region. Recently it seems, the name “Regor”, “roger” spelt backwards (!) has been applied to Gamma Vel. I can’t see this working either, despite the suggestion that it honours one of the Apollo astronauts lost in the capsule fire. Let’s persist with Gamma Velorum!

The chief claim to fame of this star is its extraordinary spectrum – which I’ve described elsewhere. Both star types O and WR are rare, the latter in particular. Yet here we have a naked eye example. WR stars have such strong stellar winds that they have blown away much of their mass in the short time (astronomically) of a million years or less – and have lost most of their hydrogen fuel. As a result they now burn helium, at ~70,000K surface temperature, creating carbon in the fusion process – the cause of Gamma2’s bright carbon bands. Perhaps 800 Ly away, the WR star is said to be 100,000 times brighter than our Sun – and, apparently, a supernova candidate.

All up, this southern star can claim to be strangest of the naked-eye stars in the whole night sky. Take a look – almost any scope will do.

Harry Roberts is a Sun and Moon observer, a regular contributor to the Sydney Observatory blog and a member of the Sydney City Skywatchers

Stars, planets and the love of the Gods

Tuesday 14 February 2012
Venus session 7pm to 8:30pm
Jupiter session 9pm to 10:30pm

Enthral your loved one this Valentine’s evening by visiting Sydney Observatory. Venus, Goddess of Love, is the focus for the 7pm twilight session. Jupiter and his lovers are featured in the 9pm session.

Each 1 hour 30 minute tour includes a glass of wine and a light supper in historic Sydney Observatory, a telescope dome tour and 3D Theatre session. Should the weather be overcast or wet, a cosy planetarium session is offered. Each couple will receive chocolates and a romantic balloon on departure.

Tickets are pre-booked and pre-paid and numbers are strictly limited. Parking is available at the National Trust exclusively for booked visitors.

Conditions:
No refunds or exchanges.
Gluten-free and vegetarian food will be available, other food intolerances cannot be accommodated.
Includes two glasses of sparkling white wine, beer and soft drink options are available.
Parking is available at the National Trust on the basis that there is no responsibility taken for persons or property outside the grounds of Sydney Observatory.

Book online or call 9921 3485.
Cost: $82 per couple ($74 per couple Powerhouse members)
Please note: all tickets are per couple – so please select 1 ticket when booking, to obtain a ticket for a couple.

Why not dazzle your Valentine with their own star?
Check our Name A Star page for information about our special Valentines offer for the first ten bookings for Sydney Observatory Name A Star viewings on Valentine’s Night.

Depending on the positioning of the dome opening, the Sydney Harbour Bridge can sometimes be seen from the south telescope dome.