Active optical alignment of off-axis telescopes based on nodal aberration theory.

Our paper mainly separates the specific aberration contributions of third-order astigmatism and third-order coma from the total aberration fields, on the framework of the modified nodal aberration theory (NAT), for the perturbed off-axis telescope. Based on the derived aberration functions, two alignment models for the same off-axis two-mirror telescope are established and compared. Among them, one is based on third-order NAT, the other is based on fifth-order NAT. By comparison, it is found that the calculated perturbations based on fifth-order NAT are more accurate. It illustrates that third-order astigmatism and third-order coma contributed from fifth-order aberrations can't be neglected in the alignment process. Then the fifth-order NAT is used for the alignment of off-axis three-mirror telescopes. After simulation, it is found that the perturbed off-axis three-mirror telescope can be perfectly aligned as well. To further demonstrate the application of the alignment method based on fifth-order NAT (simplified as NAT method), Monte-Carlo simulations for both off-axis two-mirror telescope and off-axis three-mirror telescope are conducted in the end. Meantime, a comparison between NAT method and sensitivity table method is also conducted. It is proven that the computation accuracy of NAT method is much higher, especially in poor conditions.

[1]  Bernd Harnisch,et al.  Off-axis telescopes: the future generation of Earth observation telescopes , 1998, Optics + Photonics.

[2]  Kevin W. Thompson,et al.  Influence Of Alignment Errors Of A Telescope System On Its Aberration Field , 1980, Optics & Photonics.

[3]  K. Thompson.  Description of the third-order optical aberrations of near-circular pupil optical systems without symmetry. , 2005, Journal of the Optical Society of America. A, Optics, image science, and vision.

[4]  Jannick P. Rolland,et al.  Alignment of two mirror astronomical telescopes (the astigmatic component) , 2008, Astronomical Telescopes + Instrumentation.

[5]  Robert P. Hubbard,et al.  Active optical alignment of the Advanced Technology Solar Telescope , 2006, SPIE Astronomical Telescopes + Instrumentation.

[6]  L. G. Cook.  Three-Mirror Anastigmat Used Off-Axis In Aperture And Field , 1979, Other Conferences.

[7]  Lothar Noethe,et al.  Active Optics: I. A System for Optimizing the Optical Quality and Reducing the Costs of Large Telescopes , 1987 .

[8]  Zhenwu Lu,et al.  Third-order aberration fields of pupil decentered optical systems. , 2012, Optics express.

[9]  Z. Fan,et al.  Interaction of pupil offset and fifth-order nodal aberration field properties in rotationally symmetric telescopes. , 2013, Optics express.

[10]  Yang Wang,et al.  Alignment of a three-mirror anastigmatic telescope using nodal aberration theory. , 2015, Optics express.

[11]  S. L. Hawley,et al.  Some Astronomical Performance Advantages of Off‐Axis Telescopes , 1999 .

[12]  Darren Erickson,et al.  Integrated modeling for the GPi flexure sensitive structure , 2008, Astronomical Telescopes + Instrumentation.

[13]  Victor L. Krabbendam,et al.  Active optics in Large Synoptic Survey Telescope , 2012, Other Conferences.

[14]  Jannick P. Rolland,et al.  Separation of the effects of astigmatic figure error from misalignments using Nodal Aberration Theory (NAT). , 2010, Optics Express.

[15]  William L. Wolfe,et al.  Alignment of a three-mirror off-axis telescope by reverse optimization , 1991 .

[16]  Kevin P Thompson,et al.  Multinodal fifth-order optical aberrations of optical systems without rotational symmetry: the astigmatic aberrations. , 2009, Journal of the Optical Society of America. A, Optics, image science, and vision.