The historical instruments of Armagh Observatory

vistas in Astronomy, Vol. 33, pp. 149-210, 1990 0083--6656¢90 $0.00 + .50 Printed in Great Britain. All rights reserved. ~) 1990 Pergamon Press plc.

THE HISTORICAL INSTRUMENTS OF A R M A G H O B S E R V A T O R Y

John McFarland

Armagh Observatory, College Hill, Armagh, Northern Ireland BT61 9DG, U.K.

i. Introduction

Armagh Observatory and Museum was founded in 1790 by Richard

Robinson (1709 - 1794), Lord Archbishop of Armagh and Primate

of All Ireland (1765 - 1794). Primate Robinson also founded

and endowed other establishments in Armagh such as the Public

Library in 1771. The building of an Observatory in Armagh may

have been to the Primate a step towards the formation of a

University in Ulster, as he had been interested in such an

institute (Dreyer 1883a). However, the University did not

materialise at that time.

To commemorate the long existence of the Armagh Observatory,

a committee, the Armagh Observatory Bicentenary Committee, was

formed to oversee a programme of celebratory events. This

committee met for the first time, under the chairmanship of

Archbishop Eames, on 5th June, 1989 and is composed of people

from various disciplines, not solely with scientific

backgrounds. Members include: Dr G Beveridge, Vice-Chancellor

of Queen's University, Belfast; Professor Sir Francis Graham

Smith, Astronomer Royal; The Earl of Rosse; Professor A E

Kingston, Dean of the Faculty of Science, Queen's University;

representatives from the British Broadcasting Corporation (Mr D

Bannister) and Ulster Television (Mr A Crockart); The Hon. H

O'Neill of the Northern Ireland Tourist Board; Mr J C Nolan,

Director of the Ulster Museum; Mr M Dodds of the Department of

Education Northern Ireland; The Hon. D Guinness, President of

the Georgian Society of Ireland; Dr M de Groot~ Director of

149

150 J. McFarland

Armagh Observatory; and Mr D Mitchell, Clerk and Chief

Executive of Armagh District Council.

A number of local organizing committees have been working on

the programme of events - a synopsis of which now follows.

Although not actually part of the bicentenary celebrations,

the British Astronomical Association will hold its 1990 meeting

in Armagh from 8-10 June. 1990 is the association's centennial

year and a series of postage stamps will be issued in October

1990 commemorating the bicentenary of the Armagh Observatory

and the centenary of the British Astronomical Association.

An international scientific conference will take place from

24-27 July 1990 on the topic "Surface Inhomogeneities in Late-

type Stars". This conference will also include the official

opening of the Observatory's recently re-landscaped grounds and

gardens.

From July 1990 to April 1991, exhibitions of Observatory

instruments and documents on "200 Years of Astronomy in Armagh"

will be mounted at the Armagh County Museum and the Ulster

Museum, Belfast.

The Science and Engineering Research Council's Introductory

Summer School in Astronomy and Planetary Science will be held

at Queen's University from 3-16 September 1990 and members of

the Observatory staff will be involved in the lecturing.

To involve young people in the celebrations, a schools'

astronomy competition will be launched during September 1990

with prizes to be awarded in May 1991.

A special concert by the Ulster Orchestra is to be performed

in October 1990. Also in October, the official opening of the

Observatory's new office accommodation will take place,

together with the publication of the bicentennial "History of

Armagh Observatory" by Dr J A Bennett.

The Historical Instruments of Armagh Observatory 151

A number of Visiting Scientists are to spend one month each

at the Observatory, collaborating with staff on joint projects,

during the period August 1990 to March 1991. Throughout the

duration of the celebrations, a series of popular lectures on

astronomy, architecture and gardens will be held at appropriate

times. During National Astronomy Week, 17-24 November 1990,

the television programme "The Sky at Night", hosted by Patrick

Moore, will be from Armagh. The Queen's University has kindly

agreed to hold extramural lectures on astronomy and on Armagh

in the eighteenth century.

The annual Out-of-Town Meeting of the Royal Astronomical

Society will take place in Armagh on 4-5 April 1991. At that

time there will be a commemoration of the signing by HM King

George III of the 1791 Act of Parliament establishing the

Armagh Observatory. Also in the spring the Royal Irish Academy

Discourse will be held in Armagh.

During May 1991, when the gardens are at their best, the

radio programme "Ulster Gardens" will be broadcast from the

Observatory. Finally, the celebrations will close with the

television programme "Song's of Praise" from St Patrick's Roman

Catholic Cathedral.

2. Instrumentation

As a contribution towards the celebrations to mark the

Observatory's bicentenary, we have here compiled a

chronological catalogue of the historical instruments and

ancillary equipment belonging to Armagh Observatory, to

accompany a travelling exhibition of items from the collection.

The first Astronomer of the Observatory, Revd. Dr. J. A.

Hamilton, was appointed in July 1790, and as an endowment for

the Astronomer, Primate Robinson gave twenty acres of land and

152 J. McFarland

the estate of Derrynaught. Several instruments, including a

Ramsden transit instrument and meridian circle, a Troughton

equatorial telescope and three clocks, were ordered at the

Primate's expense. However, owing to the Primate's death

before receipt of all of the instruments, the two Ramsden

instruments never came to Armagh (Robinson 1829, p.i). The

Troughton equatorial and the three clocks (including Thomas

Earnshaw's first two) did arrive. One of these clocks has been

described as unusually good (Dreyer 1883b). The then

Astronomer Royal, Revd. N. Maskelyne, advised that the clock

case should be made as air-tlght as possible. Earnshaw, being

somewhat apprehensive about constructing a clock (he was a

chronometer maker), made his now famous quotation in reply to

Maskelyne's request for a clock for Primate Robinson: "I told

him [Maskelyne] I had never made a clock, and did not know how

many wheels were in one; and asked him, if I were to make one,

how near he expected it to go. He [Maskelyne] said, he should

not allow more than half a second per day error; I replied,

that if the great clock makers, Graham, Harrison, Shelton,

Kendal and Arnold, could not make a clock go to ½ sec per day,

what hope had he that I could do it who had never yet made one"

However, Earnshaw took Maskelyne's advice and constructed the

clock. It was sent for trial to the Royal Observatory in

February 1792 (Earnshaw 1808).

The Troughton equatorial, with an aperture of 2~ inches, was

erected in 1795. With it, the declinations of thirty-seven

standard stars were measured and the results published in the

Philosphical Transactions of the Royal Society (Pond 1806).

Compensating for the non-arrival of the Ramsden transit

instrument, an Armagh watchmaker, Mr James Waugh, constructed

one, and observations with it commenced in July 1793 (Stuart

1819). Some results with this instrument were published in the

Transactions of the Royal Irish Academy (Hamilton 1810).

During the season 1794-95, Hamilton employed a 42-inch

Dollond refractor to make observations of the Sun's apparent


diameter in order to test the relative accuracy of a wire-

micrometer and an object-glass micrometer~ both by Dollond~

with a 10-inch sextant by Troughton (Hamilton 1806).

Dr Hamilton held office until 1815, when he was succeeded by

Revd. Dr. W. Davenport. During Davenport's occupation~ his

assistant~ Revd. R. Hogg, continued to use the locally-made

transit instrument. Davenport died in 1823 and he in turn was

succeeded by Revd. Dr. J. T. R. Robinson, who held office until

1882.

At the commencement of Robinson's term, the 0bservatory's

instrumentation was virtually the same as in 1795. Since there

were severe limitations in the use to which the Troughton

equatorial and the transit instrument could be put, the

then Primate, Lord John George Beresford~ ordered a new transit

instrument and a mural circle from Thomas Jones of London. The

transit instrument was erected in 1827 and the mural circle

arrived in 1831. After some improvements were made to the

mural circle, and with the aid of an electric chronograph,

Robinson commenced measuring the places of certain stars

selected from those observed by Lalande (Robinson 1879, Dreyer

1886). With these instruments, Robinson carried out the

observations which lead to the publication of the catalogue:

"Places of 5~345 Stars observed from 1828 to 1854 at the Armagh

Observatory" (Robinson 1859). In this work, Robinson gives

details of the instruments.

A Herschel reflector of ten feet focal length which had been

housed under the East dome was replaced by a Grubb reflector of

15 inches aperture in 1835. This equatorially mounted

reflector had a clock movement and the first ever three-point

floating suspension speculum mirror cell (Grubb 1932). The

mounting was constructed as an experimental model of Cooper's

equatorial~ calculated to bear a 10-foot Newtonian of Sir

William Herschel, but was capable of carrying the 15-inch

reflector (Robinson 1842).

154 J. McFarland

In 1841~ Armagh Observatory was honoured by the gracious

presentation by Her Majesty Queen victoria of part of the King

George III Collection of Scientific Instruments, formerly

housed at the King's private Observatory at Kewp Surrey. The

items sent, and the scenario relating to their journey to

Armagh were described by Dr. E. M. Lindsay, a former Director

of Armagh Observatory (Lindsay 1969), and include four

refracting telescopes, two reflecting telescopes, a Herschel

mirror, six clocks, a transit instrument, a brass quadrant, a

telescope stand~ an equatorial sector, an equal altitude

instrument~ and a zenith sector.

Following the death of Robinson, Dr. 3. L. E. Dreyer, a

Dane~ assumed the directorship. Dreyer initiated a memorial

fund for the purchase of a refracting telescope in memory of

Dr. Robinson. This fund reached the sum of £I00 and, together

with a contribution of £2000 from the Treasury, it became

possible to order a refractor of I0 inches aperture from Howard

Grubb of Dublin, and have a dome for it constructed. The lO-

inch refractor came into operation in 1885 and was used by

Dreyer to examine certain nebulae suspected of change (Dreyer

1887, 1891). Also, some objects of uncertain nature were

examined during the compilation of "A New General Catalogue of

Nebulae and Clusters of Stars" (Dreyer 1888), the catalogue

prepared by Dreyer at the suggestion of the Royal Astronomical

Society, and which is still universally referred to. Between

the years 1888 and 1893, the refractor was used to make

micrometer measures of nebulae and adjacent stars (Dreyer

1894). From 18939 observations of double stars, and

investigations of systematic errors in transit observations

were made (Dreyer 1896a,b).

A Troughton and Simms micrometer-microscope was purchased by

a grant from the Royal Society and arrived at the Observatory

in 1899 (Dreyer 1910). With this instrument, Dreyer carried

out a survey of the stars and nebulae in the galaxy Messier 33,

utilizing photographic plates exposed by Isaac Roberts (Dreyer

1 9 0 4 ) .


In 1919, the then Director, Revd. W. F. A. Elllson,

presented an 18-inch Calver reflector to the Observatory.

Ellison had acquired this instrument from John Pierce of the

Wexford Engineering Works. Studies of stellar spectra were

carried out with this reflector. With a grant from the Royal

Society~ the optical parts of this instrument were converted

into a 12"/18" Schmidt camera in 1950 by the firm of Cox,

Hargreaves and Thomson, who also provided an electronic

synchronised drive. The mounting of the Calver reflector was

retained.

Ellison completed a 6~-inch refractor in 1921 and mounted it

on the equatorial of the 15" Grubb reflector in the East dome.

This refractor also employed the clock drive of the 15-inch

Grubb reflector.

Under an international agreement involving Armagh, Dunslnk

and Harvard Observatories, a large southern hemisphere Baker-

Schmidt telescope manufactured by Perkin-Elmer came into

operation in 1950. The instrument was designed by Professor

James Baker of Harvard University and became known as the ADH

telescope. The world's then largest objective prism of 33

inches diameter was provided for the telescope through funds

from Harvard and The Queen's University of Belfast. The ADH

telescope (32"/35.6", f/3.75) was mounted on the Fecker

mounting of the 24" Bruce telescope situated at the Boyden

station of the Harvard Observatory in Bloemfontein~ South

Africa. Photographs exposed with this instrument have been

used in the study of globular clusters, cluster Cephelds~ and

the nearby galaxies, the Magellanic Clouds.

In the catalogue we have listed the instruments in

approximate chronological order of the date of manufacture.

Section A contains the instruments still at the Observatory;

Section B contains a list of the instruments no longer at the

Observatory for one reason or another, that is, sold, lost or

on loan; and Section C contains a listing of instruments not

positively identified at present. We have given a brief

156 J. McFarland

description of each instrument with maker's name, date and

serial number, wherever possible. The King George III

Collection of Scientific Instruments has, however, been given

fully in Section A (IA1.1-.19) even though several items have

been sold or are on loan. M numbers refer to the archives of

Armagh Observatory as published by Butler and Hoskin (1987).

An asterisk beside the catalogue number means that there is an

illustration of the item.

Acknowledgments

This catalogue has been complled from various Observatory

reports, published articles, and manuscripts. Without the

dedication and faithful recording of many people throughout the

Observatory's history, this catalogue could not have been

collated. The Armagh Observatory is financed by the Department

of Education for Northern Ireland. I wish to express my

gratitude to the Department for the opportunity to carry out

this work.

References

Butler, 3. &

Hoskin, M.

1987. "The Archives of Armagh Observatory",

Journal for the History of Astronomy, 18, 295.

Dreyer, 3.L.E. 1883a. "An Historical Account of the Arma~h

Observatory", p.3.

" 1883b. ibid., p.6.

Dreyer, J.L.E. 1886. Second Armagh Catalogue of 31300 Stars for

the Epoch 1875, deduced from observations made

at the Armagh Observatory during the years 1859


to 1883, under the direction of the late T.R.

Robinson, DD, FRS, and prepared for publication

by his successor, J.L.E. Dreyer, PhD, FRAS,

Dublin, xv, 159pp.

1887. "On some nebulae suspected of variability

or proper motion", Mon. Not. Roy. astr. Soc.,

47, 412; "Note on some apparently variable

nebulae", ibid. 52, i00.

1888. "A New General Catalogue of Nebulae and

Clusters of Stars", Mem. Roy. astr. Soc., 49,

p.l (See also "Index Catalogue of Nebulae,

ibid., 51, p.185 and "Second Index Catalogue of

Nebulae and Clusters of Stars", ibid., 59,

p.105).

1891. "Note o n some apparently variable

nebulae", Mon. Not. Roy. astr. Soc., 52,

i00.

1894. Trans. Roy. Irish Acad., 30, pt.13.

1896a. Mon. Not. Roy. astr. Soc., 57, 44.

1896b. Report of the Astronomer of the Armagh

Observatory for the years 1883 to 1896, p.5.

1904. Proc. Roy. Irish Acad., 25A, 3.

1910. Report of the Astronomer of the Armagh

Observatory for the years 1897 to 1910, p.3.

Earnshaw, T. 1808. "An Appeal to the Public", London.

Grubb, H. 1932. Obituary Notice: Proc. Roy. Soc. I Ser.A, 135,

No.A828, p.iv.

158 J. McFarland

Hamilton, J.A. 1806. Trans. Roy. Irish Acad., I0, 109-117.

" 1810. ibid. 11, 25-44.

Lindsay, E.M. 1969. Irish Astron. Journ., 9, 57.

Pond, J. 1806. Phil. Trans. Roy. Soc., 453-454.

Robinson, T.R. 1829. "Astronomical Observations made at the

Armagh Observatory", Vol. I, Pt.l.

" 1830. "Astronomical Observations made at the

Armagh Observatory", Vol. I, Pt. II.

" 1835. Mem. Roy. astr. Sot., 9, 17.

" 1842. Report made at the Annual Visitation of

the Armagh Observatory, p.5.

" 1859, "Places of 5~345 Stars observed from 1828

to 1854 at the Arma~h Observatory", Dublin.

" 1879. "Places of one thousand Stars observed at

the Armagh Observatory",Trans. Roy. Dublin Sot.,

1, Ser.2, I01.

Stuart, J. 1819. "Historical Memoirs of the City of

Armagh", 523-527.


Section A

IA1 His Majesty King George III C o l l e c t i o n of S c i e n t i f i c Ins truments presen ted to Armagh Observatory by Her

Majesty Queen V i c t o r i a :

.1 8-foot Achromatic Telescope by Peter Dollond of the

mural circle by Sisson. At the request of Dr Whipple of

the Kew Observatory Committee this telescope was

returned to Kew by Dreyer in 1889 - the mural circle

was in the Science and Art Department of Kew

Observatory and the telescope completed the instrument.

It is believed to have been recently moved to the

Science Museum, London.

.2 Small Journeyman Clock by Shelton. On the advice of

Professor H H Turner, Savilian Professor of Astronomy

at Oxford, this clock and items IA.3,.4,.5 were sold

for £25 to Mr W A F Wetherfield in 1918. Wetherfield's

collection was sold in 1928 and the two Shelton

journeyman clocks probably went to the USA.

.3 large Journeyman Clock by Shelton. Sold to

Mr Wetherfield in 1918.

.4 Journeyman Clock by Graham. Sold to Mr Wetherfield in

1918.

.5 Small Clock by Vulllamy. Sold to Mr Wetherfield in

1918,

.6* Transit Instrument by Adams with its reversing

apparatus and observing chair. The Adams transitj

minus its object glass, reversing apparatus and

observing chair, was loaned to Queen's, Belfast c.1851

- no trace can now be found of the Adams transit.

160 J. McFarland

IA1.7 Large A s t r o n o m i c a l N igh t C l a s s - a sma l l short-focus

telescope for use at night. Loaned to Queen's, Belfast

c.1851. No trace can now be found of it.

.8- A s t r o n o m i c a l C lock by Reco rdon . c.1762.

.9* 3.9-inch Achromatic Telescope on stand in case.

Loaned to Queen's, Belfast c.1851, returned to

Observatory minus its object glass and eyepieces.

. 1 0 - Mean T ime A s t r o n o m i c a l C l o c k by S h e l t o n . Used by His

Majesty King George IIl to obtain the exact time of the

transit of Venus in 1769.

. 1 1 " 6 - i n c h R e f l e c t o r by Thomas S h o r t , London. 1745.

2

1371 - 24, 2 feet focal length.

Includes 5 eyepieces, 1 slide filter, and angled

mirrors. Used by His Majesty King George III to

observe the 1769 transit of Venus. This telescope

could be adapted to Newtonian, Cassegraln and Gregorian

systems. M92.2 contains an old page of

instructions for using the telescope, possibly by

Short.

. 1 2 " 2 - f o o t G r e g o r i a n R e f l e c t o r .

. 13" Bras s Quad ran t by J . S i s s o n , London. 2 0 - i n c h e s r a d i u s .

Has diagonal divisions, a telescope and a plumb-line.

. 1 4 - H e r s c h e l Newtontan M i r r o r . 9 - i n c h e s a p e r t u r e , 1 0 - f e e t

f o c a l l e n g t h . Reputed to have been made w i th p e c u l i a r

c a r e f o r His M a j e s t y King George I I I .

. 1 5 " 8 - f o o t A c h r o m a t i c T e l e s c o p e by P e t e r D o l l o n d ? . With

e y e p i e c e , b u t no o b j e c t i v e .

.16- T r i a l T e l e s c o p e S t and .


.17 Equatorial Sector by Adams.

.18- Equal A l t i t u d e I n s t r u m e n t by S i s s o n .

.19 Z e n i t h Sector by S i a a o n . 4~-inch objective by Peter

Dollond, 12-feet focal length.

IA2* Brass Astrolabe (Ring dlal)

IA3* Astronomical Clock by Nudge and Dutton, c.1785.

This is the so-called Buchanan clock.

This clock had been placed in the West dome of the

Observatory. Loaned to the Dean and Chapter of the

Church of Ireland Cathedral. A clock by J. Crosthwalte

was substituted for the Hudge and Dutton clock.

(Observatory Minute Book 3/9/1844, p.38).

IA4* A s t r o n o m i c a l Clock by J . C r o a t h w a l t e , D u b l i n . c . 1 7 8 0 s .

The clock was constructed for Dr Ussher of Dunsink

Observatory. On Ussher's death it was purchased for

Armagh Observatory for 40 guineas. The clock has rubied

pallets, an eight-day movement, and rated at mean solar

time. This clock was attached to a stone pillar in the

passage to the transit room. (see Earnshaw's

Astronomical Timepieces, M129)

IA5* R e f r a c t o r by John D o l l o n d . 4 2 - i n c h e s f o c a l l e n g t h .

T h i s r e f r a c t o r was u s e d by Dr. J . A. H a m i l t o n t o make a

s e r i e s o f m e a s u r e s o f t h e S u n ' s a p p a r e n t d i a m e t e r i n

1 7 9 4 - 9 5 , i n o r d e r to t e s t t h e r e l a t i v e a c c u r a c y o f a

w i r e - m i c r o m e t e r and an o b j e c t - g l a s s m i c r o m e t e r ( b o t h by

D o l l o n d ) . See T r a n s . Roy. I r i s h A c a d . , 10 , 1 0 9 - 1 1 7 .

162 J. McFarland

IA6 A s t r o n o u i c a l C l o c k s by T h o l a s Ea rnahaw. c.1792.

.i* The transit clock, Earnshaw's first ever long-case

clock, is described by him in his "Appeal to the

Public" in 1808, where he states his claim to a

national reward for his contribution towards the

solution of the determination of longitude problem.

In manufacturing the clock, Earnshaw employed devices

used in chronometer making, among which were the use of

high numbers, small teeth, large amount of jewelling,

and a small angle of escape, 0.5 ° in the (Graham)

escapement. On the advice of the then Astronomer

Royal, Revd N Maskelyne, he made the case as nearly

air-tight as possible. The clock originally had a 9-

bar gridiron pendulum of alternate steel and brass

rods which was replaced in 1830 by a mercurial pendulum

made by Mr Sharp, Sen., of Dublin. Compensating

barometers were added to the pendulum in 1832 to

endeavour to correct for the effects of varying

atmospheric pressure. These barometers were removed

in 1835.

Extracts from M129: "The clock has an 8-day movement,

with finely jewelled pallets and pivot holes. The

winding is effected through a valve in the glass front,

which when its index points downwards is closed air-

tight; when the key with a bit of buff leather on its

shank is put into the winding hole, and a compressing

spring from the case brought to bear on it by turning

the index of the valve up; the key will run in on the

axis of the barrel, when the clock is wound, the key is

only to be withdrawn till a circular scribe on the

shank becomes visible - then the index of the valve is

to be brought back to its downward position, before the

key is to be intirel? removed. The case is made

extremely strong and with great care and attention to

make it as airtight as possible - which is effected by

laying all the necessary opens with waxed cloth, and


screwing all home by a great many screws with milled

heads".

IA6.2- Earnshaw's second clock has a 5-bar compensation

pendulum of steel and zinc, an 8-day movement, rated

at very nearly sidereal time. Its pallets and some of

the pivot holes are jewelled.

IA7* Theodolite by D o l l o n d . In case.

IA8 Object-glass Micrometer by Dollond? c. 1790s.

2½-inch aperture.

IA9* Equatorial Telescope by E. Troughton. c. 1795.

2½-inch aperture, 3-feet focal length.

The Troughton equatorial arrived in December 1795 and

was mounted, in the English style, under the south

dome on two stone piers resting on a massive pillar,

round which the staircase of the dwelling house winds.

There is no polar axis, but the right ascension circle,

4 feet in diameter, is attached to the polar pivots by

four stays. The declination circle is of the same size

and is similarly attached by stays to two pivots~ which

turn in Y's fastened to the right ascension circle. A

description of the instrument appears in Dr. Rees's

Cyclopaedia,

The equatorial was used for general observations and to

measure the declinations of standard stars (see J.

Pond, Phil. Trans. Roy. Soc., 453-454, 1806). The

correction of observations made with equatorial

instruments was the subject of a study by T. R.

Robinson the results of which were published in the

Trans. Roy. Irish Acad., 15,3, 1825. The instrument

was also employed by R. Finlay in the rocket

experiments to determine the distance between Armagh

and Dublin in 1838 (see T.R. Robinson, Trans. Roy.

Irish Acad., 19, 121, 1839).

A comment by T.R. Robinson in 1844 on the condition of

164 J. McFarland

the instrument is worth noting: "The West equatorial

while in the hands of Mr. Troughton was injured by a

frost which condensed on it moisture charged with the

sulphurous vapours of the London smoke, and spotted it

all over. I fear this change has increased with time,

and may at last corrode the brass to some depth. I

would therefore suggest that it should be painted and

varnished, which has been found sufficient to arrest

such an injury in other instruments".

IAI0* Meridian Marks.

J.A. Hamilton was responsible for the original marks.

From the Observatory Minute Book for 6 Oct 1848, p.2:

South meridian mark repaired, substituted a massive

iron ring for the former copper one. The north mark,

a light arch, is singularly so chosen for a purpose

where the utmost steadiness is required.

IAII* Sextant by Dollond with case.

Containing two lenses, one lens cap and three filters.

IAI2* Refractor by Dollond, London.

No object glass, one internal eyepiece lens, internal

diameter of mahogany tube: 2%".

IAI3* R e f r a c t o r by Dol lond , London.

2%" object glass, tripod stand, no eyepiece.

IA14- Pocket telescope.

1½" diameter, with 4 eyepiece lenses on small turret

wheel.

IA15 M e t a l rod . 18" l ong .

IA16 Two c o n n e c t e d m e t a l r i n g s .

IA17- P a r t o f Py rome te r by J . W h i t e h u r s t , Derby.


IA18* Barumeter by P. Newman, 122 Regent S t . , London.

IAIg* C e l e s t i a l Globe o n S t a n d b y H. & L . H . B a r d i n . c.1800.

18" diameter.

The inscription reads: To the Rev. Nevil Maskelyne, DD,

FRS Astronomer Royal this new British Celestial Globe

containing the Positions of nearly 6000 stars,

clusters, nebulae, planetary nebulae, &c. correctly

laid down to the present period from the latest

observations and discoveries by Dr Maskelyne,

Dr Herschel, The Rev d. F r. Wollaston, &c. &c.

respectfully dedicated by his most obedient h ble.

Servants H. & L.H. Bardin.

Sold by W. & S. J o n e s , Holborn, London.

IA20* C e l e s t i a l Globe by J . & W. Cary .

IA21* Brass O r r e r y by G i l k e r s o n & Co. , Tower H i l l , London.

c. 1810.

IA22" Two T e r r e s t r i a l O r r e r l e s .

IA23" E q u a t o r i a l Theodolite by C. Adams, London.

IA24. G r e g o r i a n T e l e s c o p e by G. Adams.

No.60.

IA25- P o r t a b l e A l t a z i m u t h T e l e s c o p e by G i l k e r s o n & Co.

2" aperture.

IA26- Transit Instrument by Thomas Jones. 1827.

3~-inch aperture, 63 inches focal length.

This instrument was described by T.R. Robinson in the

Armagh Observations for 1828 and 1829.

Power of instrument: 120 diameters, changed in 1840 to

195 diameters.

"The transit was supported by piers of Armagh marble,

166 J. McFarland

6' high, 24" by 18" at their base, 12" by 18" at top,

secured by cement and bronze dowels to a block of the

same marble, 6' by 5' and I0" thick.

A small circle made by Mr. Gardner and divided by Mr.

Grubb has been attached to the axis of the Transit.

The tube and the cones of the axis are connected by

tension-screws, as described by Sir James South (Phil.

Trans. Roy. Soc., 1826, Pt.lll, p. 423); the braces

shown in his figure are not applied. The axis is 30"

long, and the central ball 9" in diameter. The pivots

are i" diameter, of bell-metal. The instrument has, at

the eye-end, Troughton's altitude circles, but a circle

8.5" diameter, was later attached by Grubb of Dublin,

to the perforated end of the axis, in 1844. The Y's

are carried by strong semicircular disks of brass 13"

diameter and I" thick, let into the piers flush with

their surface. The adjustment for level is made at the

western Y by check-nuts on a screw; that for azimuth at

the other Y. The surfaces of the Y's are inclined at

60 ° instead of 90 ° , to reduce the effects of friction,

and are faced with Brazil pebble. The counterpoise

levers were originally similar to those which Troughton

had applied to the Greenwich transit, however, they

were seen to be unsuitable. The rollers were removed

from the annular levers and replaced by gibbets, from

which were suspended Y's, faced with agate, to take the

projecting parts of the pivots". In October 1832,

Thomas Jones came to Armagh to re-divide the circle,

and Robinson availed himself of the opportunity to have

the pivots reground. The pivots were again examined on

25 May 1839 on the occasion of a visit by Mr Dent.

The Transit Instrument and Jones Mural Circle were used

by Robinson to compile the publication: "Places of 5345

Stars observed from 1828 to 1854 at the Arma~h

Observatory". The main purpose of this catalogue was

to re-determine the positions of the stars observed by

James Bradley in the middle of the 18th century, to


which a number of other stars, chiefly from Lalande,

had been added. Several special investigations were

also entered into, such as the determination of

longitude of the Observatory by chronometers, rocket

signals and other methods (see Mem. Roy. astr. Soc. 9

4, 293-304; Trans. Roy. Irish Acad., 19, 110-146).

IA27" Mural Circle by Thomas Jones. 1831.

Diameter: 56"; 3~-inch aperture telescope of 63" focal

length.

The telescope was a duplicate of that of the Jones

transit instrument. This instrument was described by

Robinson (see Mem. Roy. astr. Soc., 9, 1835) where he

mentions the peculiar shape of the pier: "built of

Armagh marble, joggled together, and cemented with

mortar of marble lime and Loughneagh sand, which in a

few years attains the hardness of compact limestone.

The bracing circle is continuous and clasps each radius

rather than being screwed to it. The axis is 36" long

with steel pivots. The motion-wheel, a uniform plate

of copper, is 55.5" extreme diameter. The reading

microscopes are of unusual size, being 24.5" from the

micrometers to the object glasses which are triple

achromatics by Tulley of 0.75" aperture and 7" focus".

Robinson composed a paper on the constant of refraction

from observations with this instrument (see Trans. Roy.

Irish Acad., 19, 177, 1843).

In 1848, Robinson formulated the plan of converting the

mural circle into a transit circle, by adding to it a

second axis supported on a pier, and substituting a

telescope of larger aperture (7") and about the same

focal length as the original telescope. The new

telescope was made by Thomas Grubb of Dublin and was

attached to the circle, but without a second pier. Two

168 J. McFarland

small collimators were mounted in the same room on iron

pillars, north and south of the circle. These

improvements were completed in 1862 and a new series of

observations of stars selected from those observed by

Lalande at the close of the 18th century was then

commenced.

IA28 E y e p i e c e w i t h a t t a c h e d micrometer by Thomas J o ne s .

For use with the transit instrument or mural circle?

IA29 Range-finder telescope by Thomas Jones.

1½-inch aperture with scale along length of tube.

IA30* Syphon Barometer Pendulum by Rommey Robinson.

Used to correct the clock rate for changes in the

atmospheric pressure (see Mon. Not. Roy. astr. Soc.,

2, 40, 1831).

IA31* Discharge Tubes . Set of six intricately-made discharge tubes.

IA32" 1 5 - i n c h N e w t o n i a n - C a s s e g r a i n R e f l e c t o r by G r u b b . 1835 .

This telescope was made by Thomas Grubb of Dublin and

was equatorially mounted, with clock movement, under

the East dome. The mirror was of speculum metal. The

Earl of Rosse made and presented the Observatory with a

duplicate of the mirror in 1843. In the Observatory

Minute Book for 1843 it was noted that two micrometers

were applied to the declination circle, its cast iron

axis was replaced with a stronger one, and a machine to

polish the specula was completed. The mirror cell

was, it is believed, the first ever to employ a

compound triangular system of balanced levers t o

support the main mirror (see Proc. Roy. Soc., 135,

p.iv, 1932 and H.C. King in 'The History of the

Telescope', Griffin & Co., 1955). T.R. Robinson spoke

well of this telscope as the resolving power was good

enough to separate some difficult double stars (see


Phil. Trans. Roy. Soc., 159, 132, 1869). The mirror

was re-figured in 1871 by Grubb. A good observation of

the 1882 transit of Venus was obtained (see Copernicus,

3, 18, 1882). The only parts of the instrument

remaining at the Observatory are the mirror cell,

secondary mirror (3-inch diameter), and equatorial

mounting.

IA33- C e l e s t i a l G l o b e on s t a n d by W. N e w t o n , Son & B e r r y .

1836. 16-inches diameter, with compass points at base.

The inscription reads: Newton's new and improved

Celestial Globe, on which all the Stars are taken from

the elaborate and most improved Catalogue of Piazzi,

the Nebulas from Bode and the Double Stars and those

with proper motions from South. The Right Ascensions &

Declinations of the whole having been recalculated and

accurately laid down for the year 1840. By Mr W Newton.

Manufactured by Newton, Son & Berry, Chancery Lane,

London. Published 1st May, 1836.

IA34- B r a s s D r a w - t u b e of telescope with graduated circle.

No lenses, l~-inch thread for eyepiece, diameter of

main brass tube: 3-3/16 inches, total length 22".

Part of Tulley telescope?

I A 3 5 . 1 " C u p - a n e m o m e t e r b y T . R. R o b i n s o n . 1846 .

The Robinson Cup-anemometer was first erected on the

roof of the Observatory in 1846. However, regular

meteorological observations had commenced in 1833. In

1867, when the Board of Trade decided to establish

seven first class meteorological stations throughout

the British Isles, where complete sets of self-

recording instruments, working by photography, should

be in action day and night without interuption, Armagh

Observatory was selected as one of the stations. From

a note in the Observatory Minute Book, the clock work

of the registry of the anemometer had been in action

since March 1847. A description of the anemometer

170 J. McFarland

appeared in Trans. Roy. Irish Acad., [1850], 22, Pt.l,

Science, 155, 1855. The results of Robinson's

researches into the constants of the cup-anemometer

were given in Phil. Trans. Roy. Soc., 169, 777, 1878

and 171, 1055, 1880.

.2" Wind-speed R e c o r d e r by R.W. Munro, London. 1870.

Serial number II.

IA36-

IA37

IA38"

IA39"

IA40

IA41

IA42

IA43

IA44"

IA45

IA46

IA47

IA48

O r r e r y by P h i l l i p s . c . 1840s .

Two f i n d e r t e l e s c o p e s .

M i c r o m e t e r .

Clock D r i v e Gove rno r in s q u a r e - p y r a m i d box.

P a r t o f p e n d u l u m .

Concave m i r r o r in m o u n t .

Two l e n s e s i n b r a s s m o u n t s .

1-5/8" diameter and 3" diameter.

2" diameter Lens in mount, surfaces ground.

4" diameter Split-lens in brass mount.

T. Blunt, London.

E y e p i e c e h o l d e r . 3-3/8" thread.

Eyepiece mount, push fit tube, i%" diameter.

Eyepiece holder. 3-5/8" diameter thread, 6%" long.

Self-centring eclipse carriers for slides.

R.R. Beard.

IA49

IA50*

IA51

IA52

IA53

IA54

IA55"

IA56

IA57

IA58

IA59

IA60

IA61

IA62"

IA63"

The tlistorical Instruments of Armagh Obse~ato~

I / I O n Wollaston Doublet.

Box containing bronze cylinder and glass screen.

4" diameter condenser lens.

4" diameter lens in metal holder.

4" diameter lens.

Metal flange. 7" diameter.

Thermometer by Troughton and Simms.

"Gift of General Sabine" written on reverse.

Eyepiece, i" diameter lens in 2" diameter tube, 4" long

with lamp inside, terminals at front end, lens off-set.

C o n d e n s e r l e n s in b r a s s m o u n t . 3-7/8" diameter.

Micrometer eyepiece with saw-tooth slide.

7/8" diameter, 7½" long.

Eyepiece holder, i" diameter, 5½" long.

Eyepiece, brass tube with one lens.

1-9/16" diameter lens, 2%" long.

Draughtsman's rule by Ertel & Sohn in case.

13½" long.

Object Glass, 7~" diameter.

Electric Chronograph. 1865.

In 1865, T.R. Robinson purchased and presented to the

Observatory this electric chronograph for registering

transits proving of great value in increasing the

accuracy of the work. The clock movement was altered

171

172 J. McFarland

by Grubb in 1868. As a specimen of the work, Robinson

published in 1879 the 'Places of One Thousand Stars

observed at the Armagh Observatory' (see Trans. Roy.

Dublin Soc., Ser.2, I, I01, 1879).

IA64" Sellostat. c.1871.

6% inches diameter, mirror: i-7/8 inches diameter.

IA65" Two thermometers. (Inv.No.275)

IA66 18" Reflector by G. Calver. 1883.

This reflector was made for Colonel Tupman of Harrow at

a cost of £800. John Pierce of the Wexford Engineering

Works bought it for £200 to replace his 8" Wray

refractor. It was later given to Revd. W.F.A. Ellison,

a former Director of the Observatory, as a gift.

Ellison handed over the telescope to the Observatory by

a deed of gift made on 3rd January, 1919. Ellison

lightly re-figured the mirror and made some studies of

stellar spectra with it.

I A 6 7 . 1 " I 0 " E q u a t o r i a l Re frac tor by Grubb . 1885 .

Dr Dreyer started a fund to set up a telescope in

T.R. Robinson's memory. The fund reached the sum of

£i00. With this and a grant of £2000 from the

Government, the i0" refractor and a dome for it were

purchased. The telescope was mounted on 28th July,

1885 and regular work with it began in September 1885,

the first programme involving a re-examination of some

nebulae which had been suspected of change (see Dreyer,

Mon. Not. Roy. astr. Soc., 47, 412, 1886). After 1893,

micrometrical measures of double stars, together with

occasional work on phenomena such as the 1895 transit

of Mercury were carried out (see Mort. Not. Roy. astr.

Soc., 55, 213, 1895). W.F.A. Ellison was assisted by

his son Mervyn, later Director of Dunsink Observatory,

in double star observations. The pairs in Holmes' and

Schelner's c a t a l o g u e s were re-examined. Results were

TJne Historical Instruments of Armagh Observatory 173

published in Mon. Not. Roy. astr. Soc., 85, 1021,

suppl., 1925; 87, 465, 1927; 89, 138, 1928. During the

course of this work, Ellison discovered a number of new

double stars. One of the most energetic stellar

flares ever observed was seen by Dr A D Andrews with

this telescope in 1969 - it may still be a record to

this day (see "Out of the Zenith: Jodrell Bank 1957-

1970" by B. Lovell, Oxford University Press, 1973; and

Nature, 222, 1126 & 1129, 1969).

IA67.2" Filar Micrometer by Grubb. 1885.

This micrometer was presented to the Observatory by

Grubb as a contribution towards the Robinson Memorial

Fund set up by Dreyer. It was for use with the I0"

Grubb refractor.

.3* Small Micrometer for use with I0" Grubb refractor.

IA68* Micrometer by Troughton & Simms, London , i n c a s e .

With three lenses and two filters.

IA69 E l e c t r i c p h o t o - l a n t e r n .

Butcher.

IA70 Box w i t h f i l t e r on p r o j e c t i n g tube . F i l t e r d i a m e t e r : 7/8".

IA71* Thermometer on i v o r y mount by J . Newman, London .

IA72- Chronometer by W.B. Crisp, London. c.1891.

Serial number 8038.

IA73" M i c r o m e t e r - m i c r o s c o p e by Troughton & S l i m s . 1899.

The Royal Society provided £70 towards purchasing this

measuring machine. A survey of the positions of all

stars and other objects within 25 arc minutes of the

centre of the spiral galaxy in Triangulum, Messier 33,

174 J. McFarland

IA74"

IA75-

IA76,

IA77

IA78"

IA79

IA80*

IA81*

IA82"

IA83

was conduc ted u s i n g p h o t o g r a p h i c p l a t e s exposed by

I s a a c Robe r t s ( see Proc . Roy. I r i s h Acad . , 25A, 1904).

Pocket Barometer and A l t i m e t e r .

Thomas Armstrong & B r o s . , Manches ter and L i v e r p o o l .

Merid ian C a l e n d a r . L a t e 19th c e n t u r y .

Pocke t Watch. E a r l y 20th c e n t u r y .

Henry Draper E y e p i e c e .

1~" a p e r t u r e , 2~" l ong .

B e l i e v e d to be an e y e p i e c e used in the c o m p i l a t i o n of

the Henry Draper s p e c t r a l c l a s s i f i c a t i o n c a t a l o g u e .

B i n o c u l a r M i c r o s c o p e .

6~" R e f r a c t o r by W.F.A. E l l i s o n . 1920.

In 1921, Ellison mounted this refractor in the east

dome, the equatorial and clock drive being those of the

15" Grubb reflector which had been there since T.R.

Robinson's day.

A s t r o Compass in c a s e .

MK2 GA/II74 2-4

S h i p ' s n a v i g a t i o n equ ipment .

Model: BETEC 9.

M e c h a n i c a l C a l c u l a t o r .

Brunsviga, Model No.20, Serial No.260075.

L ens , mount and f i l a m e n t s .

Shor t Lens Type G.45. Ref . No. 14A/1399".

IA84 Mercury c o n t a c t .


IA85

IA86"

IA87"

IA88"

IA89

Stopwatch 1/10 sec.

VC/2534, Serial No. 12509.

Armagh-Dunslnk-Harvard Telescope. 32"/35.6", f/3.75 Cassegrain Schmidt.

The ADH telescope was of the Baker-Schmidt C 4 type,

being designed by Professor James Baker of Harvard

University (see Proc. Amer. Phil. Soc., 82, 339-349,

1940). It came into operation in 1950, and in

1951 the then world's largest objective prism, 33" in

diameter, was provided from funds contributed by

Harvard and the Department of Astronomy at Queen's,

Belfast (see Sci. Amer., p.46, July 1952). The

telescope was placed on the Fecker mounting of the 24"

Bruce refractor at the Boyden Station of the Harvard

Observatory in Bloemfontein, South Africa. The two-

mirror and corrector system give a flat field and

reduced tube length (168") compared with the classical

Schmidt telescope (see H.C. King, "The History of the

Telescope"). Among the objects studied with photo-

graphs from the ADH have been globular star clusters,

cluster Cepheids, and the Magellanic Clouds.

12"/18" Armagh Schaidt Telescope. The Calver reflector was converted into a Schmldt

telescope in 1950. The Royal Society provided a grant

for the conversion of the optical parts by the firm of

Cox, Hargreaves and Thomson, who also provided a

synchronized drive. The mounting of the Calver was

retained. Through a gift from Mr. T. Scott of Armagb,

a dome was built (see P. Moore, "Armagh Observatory

1790-1967", p.49).

Rock ing -mirror Meteor Cameras.

Two rocking-mirror cameras were designed and

constructed at the Observatory for the researches

carried out by Dr. E.J. Opik (see P. Moore, "Armagh

Observatory 1790-1967", p.49/50).

S p e c t r o s c o p e by E.B. Armstrong.

176 J. McFarland

IA90

IB1

IB2

IB3

IB4

IB5

I r l s - d l a p h r a g m Photometer. c.1955.

This instrument, designed by H. Haffner, was used to

determine the magnitudes of star images on photographic

plates.

S e c t i o n B

Transit Instrument by James Waugh. c.1793.

This 2" aperture transit instrument was employed for

making observations of the Sun, Moon and standard stars

commencing in July 1793 and continuing until 1827 when

the instrument was dismounted. Some results were

published in Trans. Roy. Irish Acad., 11, 25-44.

Some observations of Moon culminating stars were made

between 1795 and 1804, and a number of differences of

right ascension of pairs of stars observed in 1802 and

1803 at Greenwich and Armagh on the same night, were

intended to improve the accuracy of the Armagh results

(see Dreyer, p.6). Dr Hamilton also made a series of

measurements of the Sun's apparent diameter between

1794 and 1795 in order to test the accuracy of two

micrometers by Dollond (see Trans. Roy. Irish Acad.,

I0, 109-117). The transit was sold to Mr Sharpe of

Dublin (Observatory Minutes for 18 Oct 1827, p.16).

Var laZlon Compass. c.1796.

Note on inventory: Taken by Mr Holmes.

Circumferentor and stand, c.1796.

Taken by Mr Holmes.

Clock by Waugh. c.1796.

Taken by Mr Holmes.

10' Newton lan R e f l e c t o r by S i r W i l l i a m H e r s c h e l .

Acquired before 1819. I0" aperture.(See Stuart, 1819,

p.523).

This telescope was mounted in the East tower on a stone

pier. No trace of the telescope can be found. A

Herschel eyepiece is still at the Observatory and may

be part of this instrument.


IB6

IB7

IB8

Clock by Sharp.

This clock was used in 1838 in the determination of the

distance between Armagh and Dublin. It disappeared in

the 1970s.

P l a t i n u m - w i r e Micrometer by T. R. Robinson.

S i r Wi l l i am R. Hamil ton a c c i d e n t a l l y broke t h i s

mic romete r ( s ee I r i s h A s t r o n . J o u r n a l , 5, 161, 1959).

Four telescopes.

In April, 1918, Revd. C. Faris was authorized to place

four telescopes at the disposal of the Lady Roberts'

Field Glass Fund for the duration of the war, and in a

letter dated 29 April Lady Roberts wrote stating that

the instruments would be returned after the end of the

war "should circumstances permit" (see M92.11).

Registered numbers of telescopes: Z.191, Z.192, Z.193,

and Z.194.

Section C

ICI

IC2

IC3

IC4

IC5

IC6

IC7

IC8

Barometer by Smith, Bath. c. 1796.

Thermometer by Trough ton . c.1796.

Thermometer by Dollond. c.1796.

Air Pumps and R e c e i v e r s . c.1796.

E l e c t r i c a l Machine, b r a s s c o n d u c t o r , b a t t e r y and J a r s .

c.1796.

Night T e l e s c o p e . c.1796.

Sundry p a r t s o f the o l d P h i l o s o p h i c a l Apparatus o f

Dublin College. c.1796.

H o r i z o n t a l C o l l i m a t o r by Do l l o nd . Made entirely of glass (see Introduction to the Armagh

Catalogue of Stars, p.viii).

178 J. McFarland

IC9

IClO

ICll

IC12

IC13

IC14

IC15

IC16

Hadley Sextant by Troughton. i0½" radius, c.1818.

The latitude of Armagh Observatory was found to the

nearest second of a degree with this instrument.

(See Stuart 1819, p. 525).

Quadrant by Robert Hogg. 35" radius, c.1818.

Revd. R. Hogg, deputy at Armagh Observatory, built

an astronomical quadrant, with the assistance of James

Waugh (see Stuart 1819). An article, possibly by Hogg,

on "Solar Spots" appeared in the Newry Ma~azine,

Vol.lll, No.17, p.427, 1817.

Transit Instrument by Higgins. c.1818.

Referred to in Stuart's Memoirs of Armagh, p.525.

Thermometer by Healy. c.1823.

S e l f - r e g i s t e r i n g Thermometer. c . 1 8 2 3 .

Kater ' s Hygrometer. c.1823.

Robinson's Chronometer. c.1838.

Used in connection with the rocket signal method (see

Trans. Roy. Irish Acad.~ 19, p.121). A reference

appears in Armagh Catalogue of Stars, p.x.

Wind-gauge. c.1839.

Noted in the Observatory Minute Book, 12 Nov 1846,

p.46:

'Wind gauge ordered in 1839 has been erected, though

not with its graphic apparatus - vanes move with 1/3 of

the wind's velocity - about to add a clock work

apparatus, which will trace on paper, the movement and

direction, so that every variation can be referred to -

Dr Robinson requested by Government to construct two

similar ones for the Observatories of St Helena and

Toronto and one for the British Association at Kew.'


[]

IAi.6a Reversing apparatus for the Adams transit instrument.

IAi.6b Observing chair.

180 J . McFarland

1~1.8 Astronomical clock by Recordon, c.1762.


:]

IAI.9 3.9-inch achromatic telescope.

IAI.10 Mean time astronomical clock by Shelton.

182 J. McFarland

IAI.II 6-inch reflector by Thomas Short.

IAI.12 Two-foot Gregorian reflector.


'~ ;~, ~,i i~ C-

L

IAI.13 Brass quadrant by J. Sisson.

IAI.14 Newtonian mirror by Sir William Herschel.

184 J. McFarland

IAI.15

IAI.16

IAI.18

8-foot achromatic telescope (by P. Dollond?).

Trial telescope stand (?).

Equal altitude instrument by Sisson (?).


IA2 Ring dial.

IA3 Astronomical clock by Buchanan. This clock may actually be by Dutton (see "A Report on the Precision Clocks at Armagh Obse- rvatory" by J. Betts, 01d Royal Observatory, October 1989, p.25).

IA4 Astronomical clock by J. Crosthwaite, c.1785.

IA5 Refractor by J. Dollond (?) .

186 J. McFarland

IA6.1 Transit clock by Thomas Earnshaw, c.1792.

IA6.2 Astronomical clock by Thomas Earnshaw.

IA7 Theodolite by Dollond.


IA9 Equatorial telescope by Troughton, c.1795.

188 J. McFarland

• ." .? '

L:

[]

IAlOa South meridian marker.

IAlOb North meridian markers.


12

IAII Sextant by Dollond.

IAI2 Refractor by Dollond.

190 J. McFarland

• '- r

i

IAI3 Refractor by Dollond.

IAI4 Pocket telescope.

IAI7 Part of pyrometer by J. Whitehurst.


IAI8

IAI9

IA20

Barometer by P. Newman.

Celestial globe by H. and L. H. Bardon,

Celestial globe by J. and W. Cary.

c.1800.

192 J. McFarland

IA21 Orrery by Gilkerson and Co., c.1810.


IA22a Terrestrial orrery.

IA22b Terrestrial orrery.

194 J. McFarland

IA23 Equatorial theodolite by G. Adams.

IA24 Gregorian reflector by Adams.


|

°! • !

7

IA25 Portable altazimuth telescope by Gilkerson and Co.

IA26 Transit instrument by Thomas Jones, 1827.

IA27 Mural circle by Thomas Jones, 1831.

D

IA30 Syphon barometer pendulum by Romney Robinson.

IA31 Discharge tubes.


~ ~ 2 ~ '~'%~ ~"~¥

(b;! (c}~i~,-.,'::~, i. o..... ..-

IA32a Mounting for the 15-inch Grubb reflector, 1835.

IA32b Secondary mirror of the 15-inch Grubb reflector.

IA32c Clock movement for the 15-inch Grubb reflector.

IA23d Mirror cell of the 15-inch Grubb reflector.

. Y

"

2; i,

' :~

-t'

~ #

"

[A33

Celestial globe by w. Newton, Son and Berry, 1836.

[A34

Brass draw tube.


35.2

IA35.1 Cup-anemometer by T. R. Robinson.

IA35.2 Wind-speed recorder by R. W. Munro, 1870.

200 J. McFarland

IA36 Orrery by Phillips.

IA38 Micrometer.

IA39 Clock drive governor.


.~ r

44

IA44 Object-glass micrometer by T. Blunt.

IA50 Box containing bronze cylinder and glass screen.

202 J. McFarland

S " =

fj'~

,t

r~

~. ~ b • . ~ . ~ :

IA55 Thermometer by Troughton and Simms.

IA62 7-1/4 inch object glass (by Grubb for the Jones mural circle)

The Historical Instruments of Armagb Observatory 203

65ard71

IA63 Electric chronograph, c.1865.

IA64 Heliostat, c. 1871.

IA65 and 71 Set of three thermometers.

204 J. McFarland

IA67.1 10-inch Grubb refractor, 1885.

IA67.2 Bilfilar micrometer by Grubb, c.1885.


67.3

• u • _ •. : • • •

o

[ j ~:6 ?

:4: @:.[ E:~ :-i *:S

IA67.3 Micrometer by Grubb.

IA68 Micrometer by Troughton and Simms.

IA72 Chronometer by W. B. Crisp, c.1891.

206 J. McFarland

IA73

IA74

IA75

Micrometer-microscope by Troughton and Simms, 1899.

Pocket barometer and altimeter by T. Armstrong and Bros

Meridian calendar.


4

;J

"i - ' - - ' i C ' '

IA76 Pocket watch.

IA78 Binocular microscope.

208 J. McFarland

IA80 Astro compass.

IA81 Ship's navigation equipment.


82

IA82 Mechanical calculator.

IA86 The Armagh-Dunsink-Harvard Telescope.

210 J. McFarland

IA07 The Armagh Schmidt Telescope.

IA88 The rocking-mirror meteor camera.

The historical instruments of Armagh Observatory

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Transcript of The historical instruments of Armagh Observatory