NGC 5315/ SA2-100/ WRAY 16-140/ PK 309-4.2 (13540-6631) (Circinus) was discovered spectroscopically by Copeland, and was oddly not noticed in the surveys of Sir John Herschel. Dreyer recorded in the NGC as "...stellar=10.5 mag." This planetary is bright, a magnitude 9.6 and very pretty. Visually, I thought the planetary was slightly elongated at PA 50^O. Visually the observed diameter is between 3" and 5"sec.arc. and photographically 6.1"sec.arc. Sky Catalogue 2000.0 lists the diameter as 5.0"sec.arc. Using the V-VClassification is is labelled a Class II. The central PNN star is magnitude 11.3, photographically 13.4.

Hartung writes in AOST1 and AOST2: "In a beautiful field with a bright pale yellow star [SAO 252498] 4' preceding is this bright small nebula showing a strong elliptical prism image with a smaller fainter one on the violet side, from oxygen and hydrogen respectfully. The nebulae is fairly well defined, about 5"sec.arc. across and a 10.5cm (not 3" as quoted in the 'Companion to the Uranometria') shows it clearly as a bluish star while the prism image is easy in a 7.5cm. (AOST1 continues) R is estimated as about 3,500 pc."

Sanford says; "...appears as a small, disk-shaped object, differing from a star only because of its bluish-green colour in low-power eyepieces. A high-power eyepiece will show a fairly bright, featureless disk about 5 arcseconds in diameter. The central star is listed at mag 11.4."

Franschoek using a 15cm. f/8.6 Newtonian observed this planetary from a mountain pass summit, haze, thin clouds. Here he quote; "Easy as a star of 10th magnitude, perhaps with an envelope.Up to 186x shows no obvious disc. A moderately bright field star conveniently nearby allows precise focusing to be checked."

The expansion velocity of the nebula is 37.5kms^-1. Total mass of the nebulosity is 0.01 , ionised by a moderately strong electron density of 2x10⁴. In 1981, infra-red observations indicate that the nebulosity contains significant numbers of SiC particles, with an average particle size about 11.3µm. Ratio of Carbon to Oxygen, [C/O] is 2.5 - a moderately high abundance compared to most planetaries. NGC5315 is a relatively strong radio source, compared to most planetaries, but has a slow expanding envelope of >40kms^-1.

First determined by the International Ultra-Violet Explorer (IUE), the central star is spectral class WC6 with an effective surface temperature of 70 000^OK. This satellite observatory also confirmed its rare PN Type I - a unique evolution classes first defined by Peimbert in 1978. NGC 5315's PNN luminosity is estimated 1 000 times that of the Sun.

The spectral signature implies that the radial velocity is -32kms^-1 away from us. Distance is presently estimated between 1.3kpc. and 4.2kpc. (4 150 to 13 600 lty.) Sky Catalogue 2000.0 quotes the value as the mean of the two, 2.8kpc. It seems that the problem of interstellar absorption is particularly uncertain towards this region of the sky. A lower value of 1.3kpc. assumes no absorption and is based on the extinction distance. It is likely that the distance of the planetary is likely about 3.0kpc.

Surrounding Field of NGC 5315.

In the same field is SA3-23 (13525-6623), which I did not see in a 20cm., even using a O-III. Lying a mere 11'min.arc to the NW (PA 311^O), its location is easily identified between the midway point between two stars at 9.5 and 8.8, respectfully. The latter being 1.6'min.arc. at PA 60^O. Using the ESO-Strasbourg Catalogue of Planetary Nebula shows no listing of magnitude, though the size is given as 17"sec.arc. Looking at the STScI image, it is unlikely that a aperture below 40cm. would see it. Those with large apertures when checking out NGC5315, may like to report any visual sightings.

The next voyage in 1788 established the first colony in Australia. In Sydney, Captain Arthur Phillip established two portable observatories under the auspices of Lieutenant William Dawes. Its function was primarily made to observe the famous Halley’s comet that they expected to return in about 1790, (actually returned in 1835) but it was also to establish the longitude and latitude of the site and the establishment of local timekeeping. Dawes first observations were used to set the ships' chronometer for navigation purposes upon their return to England. We know little of the construction of these observatories. The location of this site is now inaccessible under the southern pylon of the Sydney Harbour Bridge. Little observational astronomy was made at this location, and no observational records exist, except a few letters. This was not surprising, as Dawes was also in charge of a small Garrison and in his duties often required actively to participate in exploring and surveying of the Sydney area, including Parramatta and the eastern edges of the Blue Mountains. The existence of this observatory was last recorded in August 1795.

Some thirty-three years were to pass, when Sir Thomas Macdougall Brisbane arrived in Sydney in November 1821 with his two astronomical assistants Charles Rumker and James Dunlop. Thomas Makdougall Brisbane was born on the 23rd July 1773 in Ayrshire, Scotland. Brisbane was educated at the University of Edinburgh and attended the English Academy at Kensington. His military career was both long and distinguished, rising through the ranks to become Brigadier-General in 1812. Applying for the Governorship of New South Wales in 1815, Brisbane had a personal desire to establish the first free-standing observatory. This was likely one of his main motivations for the job, as the southern skies had not been suitably explored. After six years waiting, Brisbane was sent to the Colony to become the Sixth Governor of N.S.W., which he held between 1821 and 1825, replacing the renown Governor Macquarie. Brisbane was already a very keen amateur astronomer and Scottish Philanthropist, of some reputation. In actuality, the initial Parramatta Observatory was Brisbane’s own private property financed completely out of his own pocket. He also employed two astronomers, as paid for the observatory structure, instruments, clocks and its library. After the Governorship in NSW lapsed, he eventually achieved the rank of General in 1841. The highest position in academia was as President of the Royal Society in Edinburgh in 1832. Brisbane died at the age of 86 on the 27th January, 1860 at Largs.

The Observatory was selected to be located in Parramatta Park, mainly for its close proximity to the old Government House. Here the skies were both clear and dark, with the first observation occurring in the open air during the summer solstice on the 22nd December 1821. Within four months, the established observatory was setup with its main 92mm. (3.75") Edward Troughton transit telescope (made in 1820), a 2-foot mural circle, an 80mm (3.25") equatorially mounted telescope and two pendulum clocks. The building was a simple wooden and canvas structure, with two metre sandstone piers - completed in March 1822. The only known plan of the Observatory exists in the main star catalogue, and was drawn by the Rev. W.B. Clarke in 1825.

Quickly, Parramatta Observatory established an extensive astronomical observing program. The primary undertaking was a catalogue of star positions of the southern skies using the mural circle, a meridian telescope, and transit telescope. Within four years (1825) the places of 7 385 stars had been determined - the basis of which became known as the Parramatta Catalogue of 7385 Stars. This major work, produced at Parramatta Observatory, was a first substantial star catalogue of the southern skies. March 1822 started the arduous task, ending with a reduced manuscript completed by March 1826. For these efforts Brisbane was rewarded by the Royal Astronomical Society in 1828 with their prodigious Gold Medal. Later, the catalogue was further reduced by William Richardson of the Greenwich Observatory in 1830, to be finally published in 1835.

Discoveries Made at Parramatta Observatory.

Dunlop and Rümker did the bulk of the observations for the catalogue, but also discovered new celestial objects unknown at that time. James Dunlop was born on 31st October 1793 at Dalry (near Glasgow) in Scotland. Christian Carl Ludwig ‘Charles’ Rümker was born on the 18th May, 1788 in Stargard, Mecklenburg, Germany.

Dunlop was to see out the whole star catalogue project, but in June 1823 Rümker, after a dispute with both Brisbane and Dunlop and left Brisbane’s employment to a farm at Reservoir Hill, Picton, NSW. (The main reason seems to be that Rumker had better qualifications than Dunlop, and this caused a degree of friction between them, especially in the credit for the observations. This lead to irreconcilable differences.) During this time Rumker’s reputation was as the first person to rediscover the periodic Encke’s Comet on its first return in 1822. Away from Parramatta, he discovered in 1824 a bright comet of his own.

Between May 1826 until October 1829 Rümker was to return to Parramatta, under some duress, as the Government Astronomer. This was mainly due to Brisbane ending his Governorship and returning to Scotland in late 1824. He remained as governor until he relinquished it on the 1st December 1825 to Governor Ralph Darling. The observatory was sold by Brisbane in the same month, to the NSW government for £1 614 13 shillings. Final payment remained in dispute for several more years.

Here Rümker pursed new observations of comets, transits observations and double stars. Of the double stars he found a total 26 (20 are recognised today.) Pairs are now designated ‘Rmk’ or ‘RMK’. Most of these pairs were discovered in the survey of bright stars for the transit programme. For the amateur, most of the pairs he discovered are rather attractive and easily seen in small or for a few, a moderate telescope.

Rümker was eventually rewarded with a Gold Medal by the Royal Astronomical Society in 1854. In retrospect, Rümker’s observations proved more the significant than the works of Dunlop. Due to these accolades, Rümker suffered some personal hostility from both Brisbane and Dunlop, even after his return to Europe in November 1830. He played no further role in southern observations. Later he became a lecturer on Navigation between 1831 and 1857, and then the director of the Hamburg Observatory in Germany between 1833 and 1857. Charles Rumker died in Lisbon, Portugal in the 21st December, 1862.

Dunlop was to be involved with Parramatta Observatory much longer. He is more recognised for the discovered many of the bright southern double stars and southern deep-sky objects, most during the observations for the Parramatta Catalogue.They are today now designated ‘ ’ or ‘DUN’. From March 1826, after leaving Parramatta Observatory, started observations of the heavens from the backyard of his home in Hunter St., near St. John’s Church, in Parramatta. Dunlop constructed his own 9-foot reflecting telescope with a 9" aperture, (2.7m. [f11.8], 22.8cm.) This is possibly the first reflecting telescope made within Australia. Having a speculum mirror the images were not as good as Dunlop had stated. John Herschel’s observational statements, while searching for Dunlop’s nebulae, indicate that it suffered from stray light, producing ghostly images and identification of nonexistent nebulae. By the end of the year 1826, Dunlop had discovered and catalogued 629 nebulae and star clusters, which was published in the Royal Society’s ‘Philosophical Transactions’. For this work he was jointly awarded, along with Sir Thomas Brisbane, the prestigious Gold Medal of the Royal Astronomical Society in February 1828. Within this time he also searched for new double stars, mainly during poor seeing conditions or moonlight, listing a total of 254. Being good with his hands, he constructed many instruments, including a simple filar micrometer and ring micrometer, measuring twenty-nine pairs that he considered to be physically associated. This paper was later read by Sir John Herschel to the Royal Astronomical Society in May 1828. Of these, many of the most prominent pairs are now frequently observed by amateurs.

His southern observational work is thought to have been completed around 1827 when he returned disappointed to Great Britain, knowing that Rümker was unlikely to give up his position. However, this was not the end of his association with Parramatta Observatory. Dunlop was requested to return to Parramatta Observatory as the Superintendent (Government Astronomer) in November 1830, after Rümker’s second and final resignation. Dunlop returned to the observatory on the 7th November 1831, almost ten years to the day of his first departure to Australia with Brisbane. However, the observatory was in a dilapidated state, that he personally undertook some of the necessary repairs to make it again a working observatory. In 1832, a residence was built about ten metres from the Observatory which Dunlop occupied it till he resigned. This building was substantially refurbished at Government expense.

Although Dunlop discovered two comets in 1833 and 1834, he is mainly recognised for his work in planetary astronomy, particularly asteroids and comets, and his transit and mural circle observations. Many of the observations made between 1832 and 1835. Unfortunately these were never reduced. His astronomical carrier was practically ended by 1839, due to illness, but he is known to have health problems as early as 1835. Time in his final halcyon days was mainly in effect spent reducing his visual observations. In these years, Dunlop produced 12 publications, including star positions and the brightness estimations of nearly 400 southern stars.

He remained as Government Astronomer until August 1847, when he resigned to the ‘Board of Visitors of Parramatta Observatory’.In his resignation letter he refers to the inadequacy of the instruments and that the Observatory was;

"...only intended as a private establishment not calculate to last beyond a few years."

The observatory had stood for 26 years!

Dunlop also stated;

"...it is my wish to try a change of scene and occupation and with what little health and strength that remains, to endeavor to weather it a few years longer."

Dunlop died a year later on the 22nd September 1848 in the town of Boora Boora, near Gosford and Kincumber on the New South Wales Central Coast.^, The place where his retirement house stands is now called Dunlop Hill. He was buried besides his wife in Kincumber. His grave stone is now close to the front door of the local church.

The Last Days of Parramatta Observatory.
The last known recorded observation at Parramatta was made on the 19th March, 1847.
The observatory was in a very poor state and totally unusable, as it was virtually destroyed by white ants by mid-1847.

On June 26th 1847 Captain Phillip King (for Governor of NSW.), Rear Admiral, Colonel John Gordon and Roger Rodgers reported on the state of the Observatory, based on an inspection made five days before. They reported;

"...very dilapidated state of repair... the floor and the partitions... entirely destroyed by the white ant and it was urgent to take measures to secure the instruments from further injury."

By the 23rd August 1847, Gordon and Rodgers recommended that the instruments and books be packed into boxes, and placed into the hands Rodgers of the Ordinance Store. After some debate about their future, the equipment was eventually passed on to Sydney Observatory in 1858. A display in the lower sections of the observatory has at the moment some of the equipment used at Parramatta Observatory in a temporary display until September 1997. You may like to see it yourself.

The residence was unoccupied after Dunlop resigned, and stood until 1879, when it was demolished to the foundations by the Park Ranger in charge of Parramatta Park, George James Giles. Most of the observatory super structure was also taken down. As for the rest of the site, the majority of the foundations of the observatory were taken out in 1887, leaving the piers of the transit telescope as a memorial. This was done by the superintendent of Parramatta Park, and the rest is the same as it is today.

A small obelisk was erected in 1880, was placed here because of a recommendation by the amateur astronomer John Tebbutt. (The same amateur astronomer placed on the first Australian $100 note.) It states;

"This obelisk was erected in 1880 to mark the position of the transit instrument."

However the kitchen of the residence was wrongly identified as the observatory, less than ten metres from the location are the unmistakable piers of the transit telescope! At the present time the two signs at the site now correct this error- for all to see.

The obelisk and the transit piers are the only sign that an observatory actually existed at the site. Fortunately, a new sign now correctly makes the position of the observatory.

Conclusion.

The development of Parramatta Observatory was an important time in the history of the colony and Australia. It was at a time when the population started to think it self more Australian rather than a British colony. In the years after the demise of the Observatory, Australia started to develop a slightly different culture. By the beginning of 1850, NSW was producing its own ‘natural philosophers’ (that we today call scientists) and University graduates. Eventually we had our own Sydney Observatory in 1858.

Astronomy is still prominent today, with our radio and optical observatories still discovering and measuring celestial objects. It is humbling to think that on this site was the beginning of observational and positional astronomy in this country.

The Transit Telescope.

The transit telescope is an established instrument, but in it days of its use it was also known as the universal instrument. The first transit telescope was established as a primary instrument somewhere between 1760 and 1780.

It's astronomical use is based on the determination of the time when a star crosses the meridian, the line that divides the eastern and western parts of the sky at the place of observation. When accurately determined, in which the transit telescope is the most famous, is the place that technically marks the local sidereal time, but more importantly the actual apparent time for that longitude. The precise graduated circles also give the star altitude on the meridian from the zenith or northern and southern horizons. Based on these two values, the precise longitude of the location can be calculated.

Longitude on the Earth is measured from the position of the transit telescope at Greenwich Observatory in England. This particular instrument marks the internationally agreed zero longitude of the world.
When the position of the transit has been substantiated, this fixed position can be used to then measure the accurate position of the stars, and over time, the motions of the stars in question. Although it is simple to explain a transit telescope, it is by no means simple to explain how the results are obtained. The regimes of mathematical calculations and of the errors are too broad based for our discussion.