Professor James Osborn's Outputs (75)

Demonstration of 24-hour continuous optical turbulence monitoring in a city (2025)
Journal Article
Beesley, L. F., Griffiths, R., Hartley, K., Farley, O. J., Quatresooz, F., Rodríguez-Gómez, A., Comerón, A., Townson, M., Alaluf, D., & Osborn, J. (2025). Demonstration of 24-hour continuous optical turbulence monitoring in a city. Optics Express, 33(5), 10140-10149. https://doi.org/10.1364/OE.543144

Atmospheric optical turbulence limits the performance of free-space optical communication links between the ground and space. The bandwidth provided by optical links enables the realization of ubiquitous, high-bandwidth and secure communications anyw... Read More about Demonstration of 24-hour continuous optical turbulence monitoring in a city.

Distortion of visible daytime multi-conjugate adaptive optics control (2024)
Presentation / Conference Contribution
Kongkaew, P., Morris, T. J., & Osborn, J. (2024, June). Distortion of visible daytime multi-conjugate adaptive optics control. Presented at Adaptive Optics Systems IX, Yokohama, Japan

Daytime optical observations, including solar telescope and free-space optical communication, experience strong turbulence and scintillation. These conditions cause control problems in Multi-Conjugate Adaptive Optics (MCAO). Considering an MCAO setup... Read More about Distortion of visible daytime multi-conjugate adaptive optics control.

Pre-distortion adaptive optics for optical feeder links: simulations and performance analyses (2024)
Journal Article
Hristovski, I. R., Osborn, J., Farley, O. J. D., Townson, M. J., Calvo, R. M., Femenía-Castella, B., Torres, J. S., Holzman, J. F., & Reeves, A. P. (2024). Pre-distortion adaptive optics for optical feeder links: simulations and performance analyses. Optics Express, 32(12), 20976-20991. https://doi.org/10.1364/oe.521494

Optical feeder links offer immense utility in meeting future communication demands—however, atmospheric turbulence limits their performance. This work targets this challenge through analyses of a bidirectional free-space optical communication (FSOC)... Read More about Pre-distortion adaptive optics for optical feeder links: simulations and performance analyses.

Exploring atmospheric optical turbulence: observations across zenith angles (2024)
Journal Article
Beesley, L. F., Osborn, J., Wilson, R., Farley, O. J. D., Griffiths, R., & Love, G. D. (2024). Exploring atmospheric optical turbulence: observations across zenith angles. Applied Optics, 63(16), E48. https://doi.org/10.1364/ao.519063

We present measurements of the atmospheric optical turbulence as a function of zenith angle using two identical instruments, Shack-Hartmann Image Motion Monitors (SHIMMs), to measure atmospheric parameters concurrently. One instrument was pointed nea... Read More about Exploring atmospheric optical turbulence: observations across zenith angles.

A comparison of next-generation turbulence profiling instruments at Paranal (2024)
Journal Article
Griffiths, R., Bardou, L., Butterley, T., Osborn, J., Wilson, R., Bustos, E., …Otarola, A. (2024). A comparison of next-generation turbulence profiling instruments at Paranal. Monthly Notices of the Royal Astronomical Society, 529(1), 320 - 330. https://doi.org/10.1093/mnras/stae434

A six-night optical turbulence monitoring campaign has been carried at Cerro Paranal observatory in February and March, 2023 to facilitate the development and characterisation of two novel atmospheric site monitoring instruments - the ring-image next... Read More about A comparison of next-generation turbulence profiling instruments at Paranal.

Continuous daytime and nighttime forecast of atmospheric optical turbulence from numerical weather prediction models (2023)
Journal Article
Quatresooz, F., Griffiths, R., Bardou, L., Wilson, R., Osborn, J., Vanhoenacker-Janvier, D., & Oestges, C. (2023). Continuous daytime and nighttime forecast of atmospheric optical turbulence from numerical weather prediction models. Optics Express, 31(21), 33850-33872. https://doi.org/10.1364/oe.500090

Future satellite-to-ground optical communication systems will benefit from accurate forecasts of atmospheric optical turbulence; namely for site selection, for the routing and the operation of optical links, and for the design of optical communicatio... Read More about Continuous daytime and nighttime forecast of atmospheric optical turbulence from numerical weather prediction models.

Optical sparse telescope arrays and scintillation noise (2023)
Journal Article
Hartley, K. E., Farley, O. J. D., Townson, M. J., Osborn, J., & Wilson, R. W. (2023). Optical sparse telescope arrays and scintillation noise. Monthly Notices of the Royal Astronomical Society, 526(1), 1235-1245. https://doi.org/10.1093/mnras/stad2835

Fresnel propagation of starlight after it passes through high altitude turbulence in the Earth’s atmosphere results in random fluctuations of the intensity at ground level, known as scintillation. This effect adds random noise to photometric measurem... Read More about Optical sparse telescope arrays and scintillation noise.

Line-of-sight optical Dome Turbulence Monitor (2023)
Journal Article
Osborn, J., & Alaluf, D. (2023). Line-of-sight optical Dome Turbulence Monitor. Monthly Notices of the Royal Astronomical Society, 525(2), 1936-1940. https://doi.org/10.1093/mnras/stad2428

Optical turbulence in the enclosure of a ground-based telescope can be a major contributor to the total optical turbulence strength and can therefore limit the precision of astronomical observations, in terms of angular resolution, or signal to noise... Read More about Line-of-sight optical Dome Turbulence Monitor.

Atmospheric optical turbulence analysis in London’s financial district (2023)
Presentation / Conference Contribution
Westerby-Griffin, L., Osborn, J., Farley, O. J. D., Griffiths, R., & Love, G. D. (2023, January). Atmospheric optical turbulence analysis in London’s financial district. Presented at Free-Space Laser Communications XXXV, San Francisco, United States

Atmospheric optical turbulence causes signal loses in laser propagation. Here we present vertical measurements of optical turbulence taken in London’s financial district. Additionally, we demonstrate a method of modelling atmospheric states in simula... Read More about Atmospheric optical turbulence analysis in London’s financial district.

The 24hSHIMM: a continuous day and night turbulence monitor for optical communications (2023)
Presentation / Conference Contribution
Griffiths, R., Osborn, J., Farley, O., Butterley, T., Townson, M., & Wilson, R. (2023, January). The 24hSHIMM: a continuous day and night turbulence monitor for optical communications. Presented at Free-Space Laser Communications XXXV, San Francisco, United States

We present the 24-hour Shack-Hartmann Image Motion Monitor (24hSHIMM), the first truly continuous, 24-hour optical turbulence monitor. Atmospheric optical turbulence is a significant limitation for free-space optical communications and other technolo... Read More about The 24hSHIMM: a continuous day and night turbulence monitor for optical communications.

First On-Sky Demonstration of a Scintillation Correction technique using Tomographic Wavefront Sensing (2023)
Journal Article
Hartley, K. E., Farley, O. J., Townson, M. J., Osborn, J., & Wilson, R. (2023). First On-Sky Demonstration of a Scintillation Correction technique using Tomographic Wavefront Sensing. Monthly Notices of the Royal Astronomical Society, 520(3), 4134-4146. https://doi.org/10.1093/mnras/stad420

Scintillation noise significantly limits high precision ground-based photometry of bright stars. In this paper we present the first ever on-sky demonstration of scintillation correction. The technique uses tomographic wavefront sensing to estimate th... Read More about First On-Sky Demonstration of a Scintillation Correction technique using Tomographic Wavefront Sensing.

SHIMM: a versatile seeing monitor for astronomy (2023)
Journal Article
Perera, S., Wilson, R. W., Butterley, T., Osborn, J., Farley, O. J., & Laidlaw, D. J. (2023). SHIMM: a versatile seeing monitor for astronomy. Monthly Notices of the Royal Astronomical Society, 520(4), 5475-5486. https://doi.org/10.1093/mnras/stad339

Characterization of atmospheric optical turbulence is crucial for the design and operation of modern ground-based optical telescopes. In particular, the effective application of adaptive optics correction on large and extremely large telescopes relie... Read More about SHIMM: a versatile seeing monitor for astronomy.

Demonstrating 24-hour continuous vertical monitoring of atmospheric optical turbulence (2023)
Journal Article
Griffiths, R., Osborn, J., Farley, O., Butterley, T., Townson, M. J., & Wilson, R. (2023). Demonstrating 24-hour continuous vertical monitoring of atmospheric optical turbulence. Optics Express, 31(4), 6730-6740. https://doi.org/10.1364/oe.479544

We report what is believed to be the first example of fully continuous, 24-hour vertical monitoring of atmospheric optical turbulence. This is achieved using a novel instrument, the 24-hour Shack-Hartmann Image Motion Monitor (24hSHIMM). Optical turb... Read More about Demonstrating 24-hour continuous vertical monitoring of atmospheric optical turbulence.

Atmospheric optical turbulence measurements at varying elevation angles (2023)
Presentation / Conference Contribution
Westerby-Griffin, L., Osborn, J., Farley, O. J. D., Griffiths, R., & Love, G. D. (2023, January). Atmospheric optical turbulence measurements at varying elevation angles. Paper presented at Free-Space Laser Communications XXXV, San Francisco, United States

The ESO’s Extremely Large Telescope Working Groups (2022)
Journal Article
Padovani, P., Cirasuolo, M., van der Burg, R., Cantalloube, F., George, E., Kasper, M., Leschinski, K., Martins, C., Milli, J., Möhler, S., Neeser, M., Neichel, B., Otarola, A., Sánchez-Janssen, R., Serra, B., Smette, A., Valenti, E., Verinaud, C., Vernet, J., Absil, O., …Vigan, A. (2022). The ESO’s Extremely Large Telescope Working Groups. The Messenger (Garching), 189, 23-30. https://doi.org/10.18727/0722-6691/5286

Correction of photometric scintillation noise via tomographic wavefront sensing: simulation and on-sky demonstration (2022)
Presentation / Conference Contribution
Hartley, K., Farley, O., Townson, M. J., Osborn, J., & Wilson, R. W. (2022, July). Correction of photometric scintillation noise via tomographic wavefront sensing: simulation and on-sky demonstration. Presented at Adaptive Optics Systems VIII, Montréal, Canada

FAST: Fourier domain adaptive optics simulation tool for bidirectional ground-space optical links through atmospheric turbulence (2022)
Journal Article
Farley, O., Townson, M., & Osborn, J. (2022). FAST: Fourier domain adaptive optics simulation tool for bidirectional ground-space optical links through atmospheric turbulence. Optics Express, 30(13), 23050-23064. https://doi.org/10.1364/oe.458659

Free space optical links between the ground and space may be severely degraded by atmospheric turbulence. Adaptive Optics, a technique allowing partial correction of this degradation, is beginning to see use in the field with the potential to achieve... Read More about FAST: Fourier domain adaptive optics simulation tool for bidirectional ground-space optical links through atmospheric turbulence.

Scintillation-limited photometry with the 20-cm NGTS telescopes at Paranal Observatory (2021)
Journal Article
O’Brien, S. M., Bayliss, D., Osborn, J., Bryant, E. M., McCormac, J., Wheatley, P. J., Acton, J. S., Alves, D. R., Anderson, D. R., Burleigh, M. R., Casewell, S. L., Gill, S., Goad, M. R., Henderson, B. A., Jackman, J. A., Lendl, M., Tilbrook, R. H., Udry, S., Vines, J. I., & West, R. G. (2022). Scintillation-limited photometry with the 20-cm NGTS telescopes at Paranal Observatory. Monthly Notices of the Royal Astronomical Society, 509(4), 6111-6118. https://doi.org/10.1093/mnras/stab3399

Ground-based photometry of bright stars is expected to be limited by atmospheric scintillation, although in practice observations are often limited by other sources of systematic noise. We analyse 122 nights of bright star (Gmag ≲ 11.5) photometry us... Read More about Scintillation-limited photometry with the 20-cm NGTS telescopes at Paranal Observatory.

Astrosat: forecasting satellite transits for optical astronomical observations (2021)
Journal Article
Osborn, J., Blacketer, L., Townson, M. J., & Farley, O. J. (2022). Astrosat: forecasting satellite transits for optical astronomical observations. Monthly Notices of the Royal Astronomical Society, 509(2), 1848-1852. https://doi.org/10.1093/mnras/stab3003

The impact of large-scale constellations of satellites, is a concern for ground-based astronomers. In recent years there has been a significant increase in the number of satellites in low-Earth orbit and this trend is set to continue. The large numbe... Read More about Astrosat: forecasting satellite transits for optical astronomical observations.

HiPERCAM: a quintuple-beam, high-speed optical imager on the 10.4-m Gran Telescopio Canarias (2021)
Journal Article
Dhillon, V., Bezawada, N., Black, M., Dixon, S., Gamble, T., Gao, X., Henry, D., Kerry, P., Littlefair, S., Lunney, D., Marsh, T., Miller, C., Parsons, S., Ashley, R., Breedt, E., Brown, A., Dyer, M., Green, M., Pelisoli, I., Sahman, D., …García-Alvarez, D. (2021). HiPERCAM: a quintuple-beam, high-speed optical imager on the 10.4-m Gran Telescopio Canarias. Monthly Notices of the Royal Astronomical Society, 507(1), 350-366. https://doi.org/10.1093/mnras/stab2130

HiPERCAM is a portable, quintuple-beam optical imager that saw first light on the 10.4-m Gran Telescopio Canarias (GTC) in 2018. The instrument uses re-imaging optics and four dichroic beamsplitters to record usgsrsiszs (320–1060 nm) images simultane... Read More about HiPERCAM: a quintuple-beam, high-speed optical imager on the 10.4-m Gran Telescopio Canarias.