Institute of Astronomy

Mr Jonathan Crass


Personal Homepage

Office: Obs O16
Office Tel: (01223) 339279
More Info (Internal)



I currently work in the Optics Group at the Institute of Astronomy under the supervision of Professor Craig Mackay. My work is focussed on the development of a non-linear curvature wavefront sensor (nlCWFS) to be used in the low order adaptive optics system of the Adaptive Optics Lucky Imager (AOLI).

My work focuses on the development of the nlCWFS through simulation, optical development and real-time control. Previous simulation work using Arroyo has shown the importance of minimising the intrinsic chromatic effects of wavefront propagation within the wavefront system itself. My current work focusses on the development of a demonstration wavefront sensor in Cambridge prior to its on-sky test on the William Herschell Telescope on La Palma in September 2013. This work includes development of the reconstruction algorithm and its migration to GPU hardware for real-time correction.

The low order AO system for AOLI comprised two EMCCDs for pupil plane imaging, a real time control system including the phase determination algorithm and initially a 241 element deformable mirror from ALPAO. The entire project is a collaboration between multiple research institutions across Europe including:

  • Institute of Astronomy, University of Cambridge, UK
  • Instiuto de Astrofisica de Canarias (IAC), Tenerife, Spain
  • Isaac Newton Group of Telescopes, La Palma, Spain
  • Technical University of Caragena (UPCT), Spain
  • University of Cologne, Germany

Selected papers

Crass, J., King, D.L., Mackay, C.D., "The Non-Linear Curvature Wavefront Sensor - From theory to practise", MNRAS (2013) - In Prep

Crass, J., King, D.L., Mackay, C.D., "The AOLI Non-Linear Curvature Wavefront Sensor: High sensitivity reconstruction for low-order AO", Proc AO4ELT3 (2013) - Submitted

Aisher, P. L.; Crass, J.; Mackay, C., "Wavefront phase retrieval with non-linear curvature sensors", MNRAS 429 2019A (2013)

Crass, J., Aisher, P., Femenia, B., King, D.L., Mackay, C.D. et al, "The AOLI low-order non-linear curvature wavefront sensor: a method for high sensitivity wavefront reconstruction", Proc SPIE 8447 (2012)


(2010 - present) -  Graduate student, Institute of Astronomy, University of Cambridge

(2006 - 2010)      -  Undergradute student, University of Manchester (3rd Year - University of California Santa Barbara)


MPhys (1st Class with Honours) - Physics with Astrophysics, University of Manchester - 2010 (3rd year - University of California Santa Barbara, USA)

Awards and Prizes

EIROforum School on Instrumentation, May 2011 - Best Poster Award

Public Engagement

I am actively involved with the Institute's public engagement activities through talks, telescope tours and external events. You can find a list of my upcoming talks on my personal website.

Professional Organisations

Institute of Physics, Associate Member

Fellow, Cambridge Philosophical Society

Fellow, Royal Astronomical Society

Page last updated: 1 September 2013 at 22:39