The Baracchi 59 (1884-1888)

4 Dec 2018

I have embarked on a fabulous observing programme – the “Baracchi 59”. It delivers all the elements of a really fulfilling programme – an intriguing set of objects, many of which truly challenge one’s powers of observation; a tremendous historical connection to an astronomer and a famous telescope; and a fascinating record of the objects’ discoveries. (And many of these objects have spectacular neighbours to entice you away!) What more can one ask for in an observing programme?

What are the “Baracchi 59”? They are the 59 unpublished visual discoveries that Pietro Baracchi made using the 48″ Great Melbourne Telescope during the years 1884-1888.

And full credit for this wonderful project goes to Steve Gottlieb who has an enviable ability to unravel astronomical mysteries!

As someone who devoured detective stories as a kid, I had always thought that detecting was simply the unravelling of a mystery: such-and-such occurred and so-and-so did it – the basic whodunnit. But I have since discovered that real detecting, a distinct aptitude held by a fortunate few, goes to a whole new level… the ability to detect that a mystery exists where none appears to exist!

Thus it was when I mentioned in an email my observation of one of my fave LMC clusters – lovely little Hodge 301 in the Tarantula Nebula. (As an aside, to my eye, one of the most gorgeous sights is tiny razor-sharp stars glittering against a background of bright nebulosity… and the tiny Hodge 301 adorning the dazzling Tarantula is a classic! But beyond visual beauty, Hodge 301 is fascinating: it is the oldest star cluster in the Tarantula Nebula at 25-30 million years, some ten times older than R136, and has lost an estimated 38-61 stars to supernovae explosions, with more explosions to come soon as three red supergiants are present in Hodge 301 that will end their lives as supernovae within the next million years. That will be something to see!)

From that small catalyst Steve unravelled the story of the now informally named “Baracchi 59”.

Curiosity led him to compare the sketches of both John Herschel (in South Africa with “a reflecting telescope of 18½ inch clear aperture, and 20 feet focus, of my father’s construction”) and Pietro Baracchi (using the 48″ Great Melbourne Telescope). Herschel’s sketch of the Tarantula shows Hodge 301 as a small rectangle or diamond-shaped group of 4 small stars; Baracchi’s sketch shows it as a small cluster (he discovered Hodge 301 on 24 Jun 1884). This led Steve to Baracchi’s other discoveries – 4 Dec 1885: Two HII knots in NGC 1313; 5 Dec 1885: MCG -05-04-012, noting that Baracchi’s sketch of the NGC 439/441 field includes this galaxy as a star, though it is not mentioned as nebulous. A (mysteriously) small haul considering he was the principal observer from September 1883 until 1893 and this led to…

“A couple of days ago I finished plowing through Baracchi’s observing logs while he was the principal observer from September 1883 until 1893. He was a careful observer — making accurate sketches with nearby field stars, measuring offsets (in time and declination) from nearby objects and computing accurate positions. His final tally was no less than 57 discoveries that are not in the NGC! It’s really a shame that neither he nor the director of the observatory (Robert Ellery) published these discoveries in one of the journals of the day, or at least passed them on to Dreyer to include in the NGC. That might have changed the general perception of abject failure of the telescope.

“As an example, between mid-March 1885 and 14 Jul 1885 Baracchi observed the Centaurus Cluster on a few nights. His primary target was NGC 4650 and a couple of others found by John Herschel (that was the mission — re-observe “nebulae” found by Herschel and try to document any change). But along the way, he ran across and documented the following objects —  NGC 4622A, NGC 4650A, ESO 322-075, NGC 4603A, ESO 322-047, NGC 4603C, ESO 323-023, ESO 499-023, ESO 323-005, ESO 323-008, ESO 323-009, MCG -07-26-057, ESO 323-019, ESO 322-102, ESO 322-099, ESO 322-100 and NGC 4696A. So, I found that Baracchi discovered 17 (previously uncredited) galaxies in the cluster. A number of these were found in a long east-west string starting at NGC 4603A and ending at ESO 323-023.  All the galaxies in this string seem to be within 5’ or so in declination, so with an undriven scope you just have to let the galaxies float through the eyepiece field! Other forays into the Hydra I cluster (Abell 1060) and the Antlia Group netted 6 and 4 new discoveries, respectively. And some of these are quite faint and certainly couldn’t have been seen by Herschel.”

Steve followed this up with a full accounting of their visual discoveries. Here is the link to Steve’s The lost deep sky discoveries with the Great Melbourne Telescope. Quite apart from being a wonderful read, it adds an unbelievable richness to one’s observation of the individual objects: I find it fascinating to examine the objects that Baracchi was observing when he stumbled upon his discoveries, then read his original notes of the discovery, plus other comments he made, along with salient comments Steve has made.

To complete the allure of these objects, here is the brief story of Pietro Baracchi himself and the Great Melbourne Telescope.

Pietro Baracchi 

Born in Florence, Italy, on 25 February 1851, Pietro Baracchi studied mathematics and astronomy, then took a degree in civil engineering. He worked briefly as an engineer in the Italian Army before leaving Italy in 1876 with two friends, Carlo Catani (a civil engineer) and Ettore Checchi (an engineer), to try their luck in the Antipodes. After failing to find work in New Zealand, they sailed on to Melbourne, and within a few weeks all three had found appointments with the Victorian Government.

Baracchi began work as an assistant at the Melbourne Observatory on 1 November but by March 1877 had joined Catani and Checchi in the Department of Lands and Survey as a draftsman; in July 1880 he passed his land surveyor’s examination with credit. In October 1882 he was transferred back to the observatory when Robert Ellery, the government astronomer, selected him to go to Port Darwin to take part in a project to determine Australian longitudes. After successfully completing his task, Baracchi returned to Melbourne in April 1883 and in August became third assistant, in charge of the Great Melbourne Telescope, undertaking a review of the southern nebulae observed by Sir John Herschel at the Cape of Good Hope in the years 1834 to 1838 (hello Baracchi 59!) He married Catherine (Kate) Petty on 30 June 1886 at St Mary’s Catholic Church; they had a son, Guido (1887-1975).

In 1892 Baracchi was promoted to first assistant and when Ellery retired on 30 June 1895 he became acting government astronomer. His position was not confirmed however until 27 December 1900, nor was a chief assistant appointed to replace him until 1907 when Joseph Baldwin joined the staff. Until then, Baracchi wrote, ‘we were left, a band of four, to carry out the meridian and astrophotographic work’. Moreover, from 1895 there were no funds for publishing the observatory’s records.

In February 1910 the Commonwealth government invited Baracchi and a party of four to the Yass-Canberra area to select a suitable site for an astronomical observatory. With a 9-inch (23 cm) refractor, donated by Jame Oddie, a philanthropist, Baracchi established a small observatory on Mount Stromlo in May 1911. He and Baldwin alternately spent one week in six testing the site until May 1913; a month later Baracchi reported that it ‘fulfilled the most essential requirements for any class of delicate astronomical work’. He led expeditions to observe solar eclipses to Bruny Island, Tasmania, in 1910 and to the Tongan archipelago in 1911. In 1914 he wrote a chapter, ‘Astronomy and geodesy in Australia’ for the Federal Handbook of the British Association for the Advancement of Science.

He was elected a fellow of the Royal Astronomical Society in 1884, and in 1897 the Italian monarch conferred upon him the Order of Knight Commander of the Crown of Italy. Apparently Baracchi was a man of ‘particularly likable disposition, with a genius for making friends’. He was best known to the general public as official weather-forecaster for the colony, a role that he did not like. To him, ‘popular meteorology’ was ‘of little practical value except as an amusement, and of doubtful credit to science’. He fought hard to have observatories relieved of meteorological duties and this was achieved in 1907.

Baracchi’s wife died in 1908. In 1915 he retired and in 1922 visited Europe for two years; after his return he lived at the Melbourne Club. He died on 23 July 1926 and was buried in Melbourne cemetery.

The Great Melbourne Telescope

The disassembled parts of the Great Melbourne Telescope (GMT) arrived in Melbourne in November 1868 aboard the ship The Empress of the Seas. It was built by Thomas Grubb of Dublin; the design and construction overseen by a committee of eminent British astronomers, who developed the telescope to explore the nebulae of the southern hemisphere skies. Were the nebulae really clouds of gas, the birthplace of stars, or were they distant clusters of stars? Only a large telescope could help resolve this question.

It was a reflector telescope with a speculum mirror of 48 inches in diameter; at the time it was the second largest telescope in the world and the largest in the southern hemisphere. There is a wonderful description of the GMT by the Irish astronomer and physicist, Thomas Romney Robinson, in the Philosophical Transactions of the Royal Society of London, 1869:

“The dimensions of the optical parts are as follow: Aperture of primary speculum, 48 inches; focal length of primary speculum, 360 inches; aperture of secondary speculum, 8 inches; focal length of secondary speculum, 74.7 inches; equivalent focal length, 1.994 inches.

“There are two large 4-feet mirrors, each mounted in its cell ready for attachment to the telescope, floating on a complicated support of 48 cups and balls connected to the ends of arms which form a series of triangular levers, and upon hanging rings around its circumference. These mirrors have a central circular opening of 8 inches in diameter to admit the passage of the cone of rays from the convex secondary mirror to the ocular. The mirrors, both primary and secondary, are of speculum metal.

“The tube of the telescope consists of three portions. The lower, or “eye end” position consists of the cell carrying the large speculum ; the central portion is a cylinder of boiler plate, about 93 inches long, to which is attached the declination axis by means of a massive cast-iron cradle and strong iron bands embracing the cylinder. The speculum cell fits to the end of this cylinder on turned surfaces, and is held to it by three strong screw-bolts.

“The upper portion of the telescope tube is made of open steel lattice-work, about 20½ feet long, fixed by turned flanges to the boiler plate cylinder by bolts and nuts.

“The secondary mirror, in its cell, is mounted in the centre of the lattice tube, about 300 inches from the surface of the primary speculum and 39 inches within the object end of the tube, and means are provided to enable the observer while at the eye end to alter this distance for focussing.

“The polar axis is 123 inches long, and its two pivots are 12 inches in diameter. The declination axis has a diameter of 22 inches at the bearing near to the telescope, and 9½ inches at the counterpoise end. The circles are divided on silver bands, and have a diameter of 30 inches.

“The driving clock is governed by a double conical pendulum of the well-known “Grubb” form. The direct driving weight is 260 lbs., and the total weight of the moving parts is approximately 18,000 lbs.

“The instrument is provided with an achromatic telescope finder, 4 inches aperture, seven negative or Huygenian eyepieces ranging in power from [pg.341] 234 to 1,000, a parallel wire micrometer, a spectroscope, and a camera for photographing telescopic images at the focus of the primary mirror, the secondary mirror being removed when the camera is used.”

But alas. The telescope never lived up to expectations, due to difficulties with constant tarnishing of its mirrors, flexure in the mirrors, and its relative unsuitability for the new astronomical techniques of photography and spectroscopy. The telescope was operated at Melbourne Observatory by a dedicated Great Melbourne Telescope Observer: Albert Le Seuer (1869-70), E.F. MacGeorge (1870-72), Joseph Turner (1873-83), Pietro Baracchi (1883-92); thereafter it was used only intermittently. How right Steve is: Baracchi’s stunning discoveries, had they been published or passed along to Dreyer to include in the NGC, might very well have changed the general perception of abject failure of the telescope!

When Melbourne Observatory closed in 1944, the telescope was sold to the Commonwealth Observatory at Mount Stromlo, Canberra. At Mount Stromlo the telescope was given a new 50-inch glass mirror, and became an integral part of Mt Stromlo’s work during the 1960s. In the early 1990s the telescope was rebuilt with two detector mosaics for the MACHO project, and the telescope in this form found the first observational evidence for dark matter.

Then in January 2003 a bushfire swept across Mt Stromlo, its firestorm destroying the majority of the telescopes and buildings. The  bushfire destroyed the GMT’s modern equipment, but left the original parts relatively unscathed as, since the early 1980s Museum Victoria had progressively been retrieving discarded parts of the Great Melbourne Telescope as Mt Stromlo rebuilt the instrument. According to the Great Melbourne Telescope Project which is working to restore the telescope to working order (there are four project partners – Astronomical Society of Victoria, Museums Victoria, Royal Botanic Gardens Victoria and the Australian Government Bureau of Meteorology) about 90 percent of the original telescope has survived.

What a history! And one can only hope that when it is restored to working order that its restoration first light is one of these objects. Meanwhile, what a tribute to observe the 59 objects that Barrachi and the Great Melbourne Telescope discovered together!

The “Baracchi 59”

Here are the “Baracchi 59” – DSS image, name, date of discovery, type, coordinates and notes.

1.  S-L 92

10 Dec 1884    OC    04 54 26.5    -68 14 51    (LMC)

2.  S-L 676

11 Dec 1884    OC  05 43 09    -70 34 19    (LMC)

3.  S-L 684

11 Dec 1884    OC  05 43 09.4     -70 34 19    (LMC)

4.  NGC 2043

18 Dec 1884    AST  05 35 33.6     -70 07 27    (LMC)

8.  NGC 4622A

19 Mar 1885    GX    12 43 49.1    -40 42 53    (Abell 3526)

20.  ESO 323-019

12 May 1885    GX    12 52 03.1    -41 27 36    (Abell 3526)

21.  ESO 322-102

22.  ESO 322-099

39.  ESO 297-012

Dec 1885    GX    01 36 24.2    -37 20 2611       

40.  LEDA 131053

Dec 1885    GX    01 34 38.7    -37 21 13    

45.  ESO 501-049

3 Feb 1886    GX    10 37 20.1    -27 33 36    (Abell 1060)

46. PGC 31444

3 Feb 1886    GX    10 36 24.8    -27 34 55    (Abell 1060)

47. PGC 31450

3 Feb 1886    GX    10 36 29.0    -27 29 02    (Abell 1060)

48. PGC 31476

3 Feb 1886    GX    10 36 41.2    -27 33 40    (Abell 1060)

49. LEDA 141475

3 Feb 1886    GX    10 36 29.2    -27 23 37    (Abell 1060)

50. IC 2584

8 Feb 1886    GX    10 29 51.5    -34 54 42    (ACO S636)

51. NGC 3258B

8 Feb 1886    GX    10 30 25.3    -35 33 49    (ACO S636)

52. LEDA 83097

8 Feb 1886    GX    10 29 45.4    -35 37 03    (ACO S636)

53. NGC 3258D

28 Feb 1886    GX    10 31 55.6    -35 24 36    (ACO S636)

54. PGC 31418

10 Mar 1886    GX    10 36 11.0    -27 27 15    (Abell 1060)

55. ESO 194-013

7 Dec 1887    GX    00 22 38.1    -48 34 52

56. Bruck 67

16 Dec 1887    OC    00 52 48.4    -73 24 41    (SMC)

57. Kron 25

16 Dec 1887    OC    00 48 02    -73 29 12    (SMC)

58. Henize SMC-N45

16 Dec 1887    C+N    00 51 41.7    -73 13 46    (SMC)

59. ESO 358-059

14 Feb 1888    GX    03 45 03.6    -35 58 21