Date and place of birth: 2 April 1944, Dundee, Scotland
Education: Edinburgh Academy, 1949--1952.
Perth Academy, 1952--1962.
B.Sc. University of Edinburgh, 1966
PhD University of Cambridge, 1969
Supervisor: Professor Sir Martin Ryle FRS.
Thesis title: `The Evolution of Extragalactic Radio Sources'.
Posts held:
SRC Research Fellowship 1969--1972, Mullard Radio
Astronomy Observatory, Cambridge, England.
Senior Assistant in Research 1972--1977, Institute of Astronomy.
Assistant Director of Research 1977-- 1998, Institute of Astronomy.
Lecturer, 1998—2001, Institute of Astronomy
Senior Lecturer, 2001 – 2004, Institute of Astronomy
Reader in Image Science, 2004 – 2009, Institute of
Astronomy
Professor of Image Science, 2009 - , Institute of Astronomy
Fellow, Corpus Christi College, Cambridge 1972 -- present.
Bursar for Leckhampton 1992 - 1996
Member, Instrument Definition Team for the European Space Agency Faint Object Camera of the Hubble Space Telescope 1976 – 1997.
Member of various committees of the UK Particle Physics and
Astronomy Research Council (PPARC) and the University of
Cambridge.
Member of IAU Commission IX (now under Division IX) Working Group on Detectors
Project Manager of the Cambridge Infra-Red Survey Instrument (CIRSI).
Member of the Cambridge Deep Sky Initiative Team.
Project Manager for the Cambridge Infra-Red Panoramic Array Survey Spectrograph (CIRPASS)
Member of the International
Astronomical Union Commission IX (now under Division IX) Working Group on
Detectors
Teaching Experience
Undergraduate Teaching:
Organiser of the Part II Astrophysics course since its inception in 1995. Work includes all aspects of organising admissions, lecturing co-ordination, supervision management, student liaison, director of studies liaison, course quality evaluation and feedback to lecturers and supervisors, etc.
Taught the Introductory Astrophysics Lecture course, 24 lectures, 1998-2001 inclusive, and Topics in Contemporary Astrophysics, 2002-6 and 2008-present
Graduate Teaching:
Supervised graduate students in the Institute of Astronomy and the Cavendish Laboratory since 1972, a total of approximately 14 students.
General Lecturing:
Given a very great number of lectures including seminars, conference reviews and paper presentations, popular lectures, including (for >20 years) talking to groups of local schoolchildren on general astronomy.
Current Research Interests of Craig D Mackay.
1. The use of image selection techniques to achieve high resolution imaging through turbulence both from the ground for astronomy and also for ground-ground surveillance work (Lucky imaging).
2. The design and development of visible (Charge Coupled Device) and Infra-red (Rockwell MCT) detector systems for use in astronomy and other applications.
3. Development of COAST (Cambridge Optical Aperture Synthesis
Telescope) with the MRAO (Baldwin & Warner).
4. Active and Adaptive Optical Systems.
5. Development of OH suppression spectrographs and other near IR
instrumentation.
6. The Application of Visible and Near IR Detector systems in a variety of non-astronomical imaging areas.
The main theme that runs through the research programmes with which CDM has been involved over the years is that of detectors and detector systems, both in the visible and in the near infrared. The wide range of research projects that CDM has been involved in to a greater or lesser extent are listed below:
L3CCD (low light level charge coupled device development):
Marconi (Chelmsford) are probably the world leader in manufacturing charge coupled device (CCD) detectors for scientific applications. They have recently developed and have patented a completely new technique which essentially eliminates the readout noise from a CCD imaging systems even at the highest pixel rates. By extending the output register and allowing it to be run so as to trigger a small amount of avalanche multiplication each time the charge is transferred along the extended output register Marconi are able to provide a substantial gain which may be adjusted by changing the clock voltages and which itself is essentially noiseless. Marconi developed this technique to allow them to eliminate image intensifiers in low light level surveillance systems and still give photon limited noise performance even at the very lowest light levels.
CDM managed to acquire one of these low light level CCDs (L3CCDs) in order to evaluate their potential for scientific imaging applications. The results were truly astonishing, and significantly exceeded the claims that Marconi made for their technology. A paper (Mackay, SPIE, vol 4306, Feb 2001) has been published (and been widely cited) covering the results obtained. In essence it proved to be remarkably easy to produce photon shot noise limited images at the lowest signal levels (<< 1 detected photons per pixel per frame) even at high pixel rates (several MHz). Following this a prototype camera was constructed based on an existing camera to use on a telescope on La Palma in July, 2001. The tests carried out produced images with better resolution from the ground than have been obtained in space with the Hubble Space Telescope, and reached nearly 1000 times fainter than was achieved with the same system but using a standard Marconi scientific CCD
Lucky Astronomy:
For short periods of time the atmosphere can stabilise so as to allow a ground based telescope of moderate size (~2.5 m) to produce diffraction limited images. Using a detector system that can work with extremely short exposures (~10 msec) is possible to record images and select those which show good image quality, as determined by their Strehl ratio. These may be shifted and added to produce diffraction limited images from a small fraction of the total observing time within which conditions are extremely good. The advantage of this method is that it allows ground based diffraction limited imaging to be undertaken at a much in fainter level than is normally possible even with adaptive optics. This arises because the conventional adaptive optic system would normally use a Shack Hartmann screen, and require that the natural guide star should be visible in each of the sub apertures (~50 cm diameter typically) whereas this method only requires the star to be visible using a telescope aperture 25 times larger. If there is one object in the field a few which is bright enough to allow the Strehl ratio of that frame to be assessed then after many images are selected and coadded it is possible to detectors objects that are much fainter and which are invisible in the individual frames.
A system has been developed using the L3CCD described above and used (with Baldwin, Tubbs and Cox) on the NOT telescope on La Palma. The advantage of the L3CCD is that there is no noise penalty in running the camera and very high speeds, so the limitation normally experienced with a standard CCD which gave the limiting magnitude of approximately 6.5, with the L3CCD we achieved a limiting magnitude of approximately 16.5. Observations of the cores of globular clusters have produced images which have slightly better resolution than the Hubble space telescope has from space.
CIRPASS (Cambridge IR Panoramic Array Suppression Spectrograph):
This is a new instrument which offers OH suppression spectroscopy in the near infrared (J (1.3 micron) and H(1.6 micron) bands). It uses a large camera with the fibre feed. The image from the telescope is projected on to a large number of fibres each with an integral microlens in a hexagonal packed array. At the output of the fibre light-pipe the fibres are arranged into a line to make a slit which feeds a high-resolution spectrograph. The spectrograph projects a spectrum of the slit light onto a spherical surface on which are marked a series of non-reflecting lines to match the positions of the bright OH emission lines in the sky spectrum. Alignment of the mask lines with the atmospheric lines allows the OH suppressed by a large factor. The emission from the night sky in the near infrared is dominated by bright OH emission lines so that the continuum is perhaps only 2% of the total sky brightness. The light is then reflected from the spherical mask and is re-imaged onto an infrared detector. CIRPASS is initially intended to go onto Gemini North telescope. It will be used initially with a Hawaii 1024 by 1024 HgCdTe infrared detector. The Institute of Astronomy is a member of the consortium that is funding the development of the Hawaii-II HgCdTe detector family of 2048 by 2048 pixels. CDM is the project manager for CIRPASS. He is involved in the design and development of the detector systems for the instrument as well.
CIRSI (Cambridge IR Survey Instrument):
This instrument is a direct imaging camera which uses four Hawaii 1024 by 1024 HgCdTe near infrared detectors. The four chips are arranged in an array so that the space between them is slightly less than the size of an individual detector. With four position imaging it is possible to take an image without any gaps of 4000 by 4000 pixels. CDM is the project manager for CIRSI, and was also responsible for be development of the infrared detector systems used in CIRSI. CIRSI uses a AstroCam 4100 CCD controller interfaced to the HgCdTe chips via a special multiplexor box that allows each of the 16 quadrants to be read out sequentially. The controller provides a wide range of facilities including variable gain, variable pixel rate and subarray readout. The system has been able to produce images with a system readout noise of approximately eight electrons RMS in a single read. CIRSI has now been used extensively on the INT (2.5m) and WHT(4.2m) telescopes of the La Palma Observatory, Canary Islands as well as on the 100 in telescope of the Las Campanas Observatory, Chile, operated by the Carnegie Institution of Washington based in Pasadena, California.
COHSI (Cambridge OH Suppression Instrument):
COHSI was a prototype OH suppression instrument that was the fore-runner of CIRPASS. CDM's involvement in this was relatively small, principally providing the detector systems which used Rockwell PICNIC 256 by 256 HgCdTe near infrared arrays as the detectors.
COAST (Cambridge Optical Aperture Synthesis Telescope):
COAST is a multi-element optical interferometer. It uses four telescopes to bring the light together and create interference fringes from the light from relatively bright stars over a baseline of up to 100 m. CDM's involvement in COAST has been quite extensive over the years, principally in the role of providing detector systems for the telescope.
The science detectors that have been used on COAST since the beginning are avalanche photodiodes used in photon counting (Geiger) mode. This system was originally developed by Nick Nightingale, supervised by CDM. The initial configuration of COAST used an AstroCam 3200 CCD controller with a small area CCD chip to provide the acquisition and guiding system for all four telescopes simultaneously, a system constructed by Graham Cox with CDM involvement. More recently that system has been upgraded to use of an AstroCam 4202 CCD controller. In addition a new detector system that allows the spectrum of the fringe pattern to be detected has been developed. This uses another AstroCam 4202 controller and an EEV CCD 30-11 back thinned CCD chip.
Another detector system that has been provided for COAST is a fringe detection system based on a Rockwell NICMOS-III 256 by 256 HgCdTe near infrared array. This has been interfaced to an AstroCam 3200 CCD controller by Martin Beckett under the supervision of CDM.
JOSE (Joint Observatory Site Evaluation):
The Joint Observatory Site Evaluation program was a very expensive program rather poorly managed by the Royal Observatory Edinborough. The more successful part of it was Shack-Hartmann sensor system which used an 8 by 8 lenslet array and a high speed AstroCam 4100 CCD controller driving a Loral 64 by 64 frame transfer CCD. This was work done principally by David St Jacques at the Mullard Radio Astronomy Observatory (now known as Cambridge Astrophysics) with some assistance from CDM. It has providing a very substantial amount of high-quality seeing information from the upon site.
Aperture Masking
The first attempts at making diffraction limited images using optical telescopes and leading on to the use of closure phase for the first time to make high-resolution diffraction limited optical images from the ground was done by a technique called aperture masking. The technique was invented by John Baldwin of the Mullard Radio Astronomy Observatory (now known as Cambridge Astrophysics). The first experiments were done by CDM and Chris Haniff on the University of Hawaii 88 inch telescope on Mauna Kea. More recently other systems have been built and used on the INT and WHT telescopes on La Palma. CDM's involvement has principally been providing detector systems for these experiments as well as some special software to allow fast CCD readout modes to be available even with a slow-scan CCD system.
Hubble Space Telescope
CDM was a member of the Faint Object Camera (FOC) Instrument Science Team for the Hubble Space Telescope from its beginning. This involved an infinite number of committee meetings but it did lead to a very satisfactory instrument. The instrument consisted of two channels each equipped with photon counting detector systems that allowed the only inaging that actually reached the diffraction limit of the HST. It proved to be one of the longest surviving instruments on the HST. The first data obtained with it was very greatly affected by the problems with the HST mirror. It was particularly important in the UV part of the spectrum where the CCD based WFPC was not very efficient. After the HST mirror performance had been improved by the COSTAR addition at the HST first refurbishment mission, a substantial number of papers were produced by the team.
CCD Development
One of the earliest CCD systems that was built for astronomical imaging was constructed in Cambridge. At that time there were only one to other systems, developed by JPL in the United States, that had been built for astronomy. This system built in Cambridge was constructed by Jonathan Wright, supervised by CDM. This was first used on the 36 in telescope of Steward Observatory on Kitt Peak, Arizona, in 1980. Following that a new CCD system was built by CDM and used on the Anglo-Australian Telescope (AAT) in 1981. This was the first time that the drift-scan technique was used on a telescope. The idea of drift scanning (moving the chip while integrating the signal from the sky in synchronism with the charge being transferred across the CCD as it was read out) was originally developed by CDM in order to allow very non-uniform CCD chips to be used for extremely low level imaging. Imaging very faint, high redshift galaxies calls for very high accuracy for flat-fielding CCD chips to allow objects that are a tiny fraction of the background light level to be detected. CCD chips which are seriously non-uniform (and the first ones used had non-uniformities of the order of 30 percent at the peak) are extremely hard to flat-field calibrate.
The observing run on the AAT telescope also included the first use anywhere of a CCD system on an astronomical spectrograph. The first spectroscopic data taken with the device were especially interesting because they showed for the first time the ability of the detector to obtain data beyond the normal wavelength limits of photocathode detectors to provide information out to beyond one micron wavelength.
After that, observing campaigns were mounted to the Multi-Mirror Telescope (MMT) in Arizona (1982 and 1983) and to Kitt Peak National Observatory four metre telescope (1982). It was this last observing run that produced some of the faintest data ever taken with a ground based telescope. The results lead to extremely faint galaxy counts (this work was done by Penny Hall, supervised by CDM). The images produced showed that there were faint objects detected with good signal to noise at a density of 100,000 per square degree at high galactic latitudes (in the north galactic pole plane field known as SA 57). It is only very recently with HST long exposure data that galaxy counts at high latitudes have approach this sort of level. These results were published in
Following that series of campaigns the CCD system was again improved and upgraded to make it more reliable and provide a wide range of facilities for the observer and in particular for spectroscopists. A CCD system was manufactured at the Institute of Astronomy in Cambridge for use on the University of Hawaii 88 inch telescope on Mauna Kea under an arrangement whereby Cambridge was awarded time in return for providing the CCD system. This lasted for several years and provided a lot of very useful data.
Silicon Vidicon Development
In the early 1970s, before the advent of CCDs, the realisation that electronic detectors were likely to provide substantially better data was beginning to occur. Jim Westphal at Caltech had developed a silicon vidicon TV system in which the silicon vidicon was read out in slow scan mode to provide good quality pictures with a device that had intrinsically very high quantum efficiency. A silicon vidicon system was also developed at the Institute of Astronomy in Cambridge by CDM although it turned out that this development work was overtaken by progress with CCDs also carried out in the same group in Cambridge. This silicon vidicon development work was started in 1976 and lead to a CCD silicon vidicon system being used on 36 in telescope of Steward Observatory in 1980 at the same time as the prototype CCD system built by Jonathan Wright which used a large of the imaging modules developed by CDM for the silicon vidicon system.
Radio Source Structure
The PhD thesis written by CDM was on the "Evolution of Extragalactic Radio Sources", supervised by Prof Sir Martin Ryle, FRS. This involved using the One-Mile Radio Telescope of the Mullard Radio Astronomy Observatory to observe a sample of 200 bright radio sources in the 3C revised catalogue, at galactic latitudes greater than 20 degrees. A significant part of the work was the identification of the optical counterpart of these radio sources. It quickly became clear that the quality of data that was available was very mixed and generally was rather poor. For this reason CDM started taking an interest in the detection of faint galaxies and quasars. It was this interest which ultimately lead on to be needed to develop detectors since at that time it was clear that optical astronomers could build large, beautiful telescopes but had not a clue about building good quality efficient detectors.
1. Student: R J E Kraft, Admission Date: 1.10.72, Title: Automatic plate measurement and clusters of galaxies. Result: Accepted M.Sc - 11.10.79
2. Student: D Carter, Admission Date: 1.10.73, Title: The structure of elliptical galaxies. Ph.D Awarded: 14.10.77
3. Student: R Davies, Admission Date: 1.10.75, Title: The Dynamics of Elliptical Galaxies, Ph. D Awarded: 1979
4. Student: D M Whittle, Admission Date: 1.10.77, Title: The narrow line region of active galaxies. Ph.D Awarded: 8.10.82
5. Student: J F Wright, Admission Date: 1.10.78, Title: The application of imaging charge coupled devices in astronomy. Ph.D Awarded: 14.1.83
6. Student: Miss P Hall, Admission Date: 1.10.81, Title: An analysis of faint galaxy counts from CCD observations. Ph.D Awarded: 23.11.84
7. Student: M M Colless, Admission Date: 1.10.83, Title: Low resolution spectroscopy of distant galaxies. Ph.D Awarded: 24.4.87
8. Student: C A Haniff, Admission Date: 1.10.84, Title: High resolution imaging with ground-based optical telescope. Ph.D Awarded: 19.2.88
9. Student: N S Nightingale, Admission Date: 1.10.87, Title: Stellar interferometry-detectors and the atmosphere. Ph.D Awarded: 4.10.91
10. Student: M G Beckett, Admission Date: 1.10.91, Title: High resolution infrared imaging. Ph.D Awarded: 19.1.96
11. Student: Ms K A Ennico, Admission Date: 1.10.94, Title: The evolution of faint galaxies observed with Cambridge OH suppression instrument. Ph.D Awarded: 20.11.98
12. Student: R N Tubbs, Admission Date: 1.10.99, Title: Lucky Exposures: Diffraction Limited Astronomical Imaging through the Atmosphere. Ph D Awarded: 11/2003.
13. Student: Nicholas Law, Admission date: 1.10.03, Title: Lucky Imaging: Diffraction Limited Imaging from the Ground in the Visible. Ph D Awarded: 06/2006.
14. Student: Timothy Stayley, Admission date: 1.10.07, Title: Ph D Awarded:
Major Grants Held: (several smaller ones of under £100,000 are excluded)
Mackay, "Ground-Based High-Resolution Imaging in the Visible: The Cambridge Lucky Aperture Synthesis Instrument". 1/7/08-31/12/2010, £626,665, STFC
Mackay & Lasenby, "Enhanced Resolution Surveillance Imaging Systems for Crime Prevention & Detection",1/10/04-30/9/07, £270739, EPSRC, GR/S98177/01
Mackay, "OPTICON European collaboration on detector development (L3CCD controller, DSP and systems design)", 1/1/04 – 31/12/09,£220000, EU FP5 JRA3
Gilmore, Mackay + 11 others, "Observational Astronomy Rolling Grant", 1/10/01 - 30/9/05, £1,058,958, PPARC, PPA/G/O/2000/00039
McMahon, Parry, Mackay, Bland Hawthorn, "DAZLE: Dark Ages Lyman Alpha Explorer", 1/6/00 - 31/5/03, £610,610, PPARC, PPA/T/S/1998/00887
Ellis, Mackay, Parry, "Deep Sky Initiative (COHSI & CIRPASS)", 1/10/95 - continues, £1,213,748, R & B Sackler Foundation
Ellis, Parry, Mackay, "Infrared Spectrograph (COHSI)", 1/10/94 - 30/9/96, £151,000, PPARC, GR/J79300
Baldwin, Warner, Mackay, "Cambridge Optical Aperture Synthesis Telescope (COAST)" , 1/7/87 - 31/10/94, £830,000, PPARC, GR/E15735