MERLIN
Alternative names | MERLIN |
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Organization | |
Location | England |
Website | www |
Telescopes |
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Related media on Commons | |
The Multi-Element Radio Linked Interferometer Network (MERLIN) is an
The array consists of up to seven
Some of the telescopes are occasionally used for
MTLRI
In 1973, Henry Proctor Palmer made the suggestion of extending the interferometer links already in place at Jodrell Bank at the time, which started the planning of the telescope array.[6][7] Construction started in 1975.[7] The system was originally officially called MTRLI (Multi-Telescope Radio Linked Interferometer), but was commonly referred to by the simpler name of MERLIN. It originally consisted of either the 76m Lovell Telescope or the 25m Mark II, along with the 25m Mark III at Wardle, the 85 ft at Defford and a new telescope at Knockin. This new telescope was made by
The construction of the new telescope, the installation of microwave communication links and the construction of the correlator were jointly called "Phase 1" of the MERLIN project, the funding for which was approved on 30 May 1975.[10] The construction of the new telescope started on 9 July 1976, and was completed by 8 October 1976. The telescope was first controlled remotely from Jodrell in January 1977.[11] The microwave links were installed in May 1978.[12] The first observations using the system – measurements of 30 distant radio sources – were taken in January and February 1980.[13] The final cost of phase 1 of the system was £2,179,000 (1976).[13]
Two additional telescopes were added in Phase 2 of the project, along with their radio links to Jodrell Bank. While it was originally proposed that one of the telescopes would be sited at Jodrell Bank and the other at Darnhall, the pair were finally sited at Pickmere (also known as Tabley) and Darnhall. The two telescopes were the same as that at Knockin. Construction on both telescopes started on 9 April 1979, and was completed by 31 October 1979. The Pickmere telescope was connected into MTRLI for the first time on 20 July 1980, followed by the Darnhall telescope on 16 December 1980. The second phase was formally completed on the 31 December 1981, and had cost £3,142,210.[14]
The longest baseline of MTRLI was 134 km, between Pickmere and Defford.
When the Mark II's surface was replaced in 1987, it could be used along with the three E-systems telescopes on the 22 GHz frequency, expanding MTRLI at that frequency.[8] One of the 18 m dishes of the One-Mile Telescope was temporarily used in MTRLI from 1987 until autumn 1990, which greatly improved its resolution.[16]
MTRLI was renamed to MERLIN in the early 1990s, and shortly afterwards the addition of the purpose-built 32 m Cambridge antenna in 1991 increased both the sensitivity and angular resolution of the array. The array also had a new correlator and new, cooled receivers, and some of the microwave links between the telescopes were improved so that the array could observe both hands of polarization.[17]
Since 1996, carousels for the different receivers on each of the E-systems telescopes and the Mark II telescope were installed (the Cambridge telescope already had such a system installed), providing frequency agility. In 1997 and 1998, dual-frequency (5 and 22 GHz) observations were made with the array for the first time.[17]
There are plans to construct a telescope in Ireland that would be added to the array.[18]
Current MERLIN telescopes | |
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Name | Coordinates (links to map & photo sources) |
Lovell Telescope | 53°14′10.50″N 02°18′25.74″W / 53.2362500°N 2.3071500°W |
Mark II | 53°13′51.62″N 02°18′34.16″W / 53.2310056°N 2.3094889°W |
Defford | 52°05′27.61″N 02°08′09.62″W / 52.0910028°N 2.1360056°W |
Knockin | 52°47′23.9″N 02°59′44.9″W / 52.789972°N 2.995806°W |
Pickmere | 53°17′18.4″N 02°26′38.4″W / 53.288444°N 2.444000°W |
Darnhall | 53°09′21.6″N 02°32′03.3″W / 53.156000°N 2.534250°W |
Cambridge | 52°10′1.2″N 0°2′13.4″E / 52.167000°N 0.037056°E |
Goonhilly[20] |
50°02′53″N 05°10′55″W / 50.04806°N 5.18194°W |
e-MERLIN
MERLIN used
Another major development which is part of the upgrade is frequency flexibility — the ability to alter the observing band of the entire array in a matter of minutes using rotating carousels of receivers. Some telescopes in the array already had this capability, while the rest required the visit of an engineer to change the receiver. When e-MERLIN becomes operational the telescope will be able to switch rapidly between 1.4, 5, 6 and 22 GHz. This is required in order to take advantage of optimum conditions for high frequency observations where atmospheric conditions can severely affect results.[citation needed]
Work started on the e-MERLIN upgrade in May 2004 and it was completed in 2009.[22][23]
STFC's Programmatic Review 2007–08
On 6 March 2008 the Science and Technology Facilities Council (
On 8 July 2008 STFC presented their final version of the programmatic review at a Town Meeting at the Royal Society stating: "Given the strategic importance of e-MERLIN to the future of UK radio astronomy and to the highly ranked SKA project, we are working with the University of Manchester and other stakeholders to find a viable way in which e-MERLIN operations can be supported in the medium term on a shared cost basis. We have made provision for STFC support of operations to be made available to facilitate such a solution."[27]
Scientific results
Among many other things, MERLIN has been used to observe:
- Radio-loud galaxies, for example Messier 87.[15]
- Quasars, for example 3C 418.[28]
- Spectral line observations of Hydroxyl (OH) in interstellar gas clouds.[29]
The telescope can also be used for highly precise astrometry.[30] In 1998, MERLIN in conjunction with the Hubble Space Telescope discovered the first Einstein ring.[31] The telescope has also been used in combination with the VLA to carry out a weak lensing analysis.[32]
References
- S2CID 4338231.
- ISBN 0-19-858178-5.
- ISBN 0-333-55195-8.
- S2CID 118401963.
- ISSN 0035-8711.
- ^ Lovell, Jodrell Bank Telescopes, p. 184
Lovell, Astronomer by Chance, p. 312 - ^ a b c Davies et al. (1980)
- ^ a b c "JBO – MTRLI". Retrieved 10 June 2007.
- ^ Lovell, Jodrell Bank Telescopes, p. 185
- ^ Lovell, Jodrell Bank Telescopes, p. 191
- ^ Lovell, Jodrell Bank Telescopes, p. 201
- ^ Lovell, Jodrell Bank Telescopes, p. 203
- ^ a b Lovell, Jodrell Bank Telescopes, p. 204
- ^ Lovell, Jodrell Bank Telescopes, Chapter 20 (pp. 208–215)
- ^ a b Lovell, Jodrell Bank Telescopes, p. 220
- ^ "MERLIN: The 32-metre Telescope". Merlin.ac.uk. Retrieved 17 August 2010.
- ^ a b "JBO – MERLIN". Retrieved 10 June 2007.
- ^ "Irish giant could get new partner". BBC News. 2 October 2000. Retrieved 6 April 2007.
"A Radio Telescope for Ireland". Archived from the original on 7 April 2007. Retrieved 6 April 2007. - ^ "MERLIN user guide – 4.1 Location of Telescopes". Retrieved 1 September 2010.
- ^ "GHY-1 ARTHUR". Retrieved 12 December 2019.
- ^ "'Superscope' yields first glimpse of Double Quasar". BBC. 10 December 2010.
- ISSN 1742-6588.
- ^ "Giant UK telescope gets upgrade". BBC News. 26 May 2004. Retrieved 5 April 2007.
- ^ Smith, Lewis (12 March 2008). "Jodrell Bank to close because scientists voted for own plans". The Times. London. Retrieved 12 May 2010.
- ^ "STFC Consultation - Comment". Archived from the original on 2 August 2008. Retrieved 15 August 2008.
- ^ "Archived copy" (PDF). Archived from the original (PDF) on 27 February 2009. Retrieved 15 August 2008.
{{cite web}}
: CS1 maint: archived copy as title (link) - ^ "Archived copy" (PDF). Archived from the original (PDF) on 27 February 2009. Retrieved 12 April 2009.
{{cite web}}
: CS1 maint: archived copy as title (link) - ^ Lovell, Jodrell Bank Telescopes, p. 221
- ^ Lovell, Jodrell Bank Telescopes, p. 224
- ^ Lovell, Jodrell Bank Telescopes, p. 226
- ^ "A Bull's Eye for MERLIN and the Hubble". Retrieved 10 June 2007.
- S2CID 55876431.