A conceptual design for a Cassegrain-mounted high-resolution optical spectrograph for large-aperture telescopes

Cynthia S. Froning, Steven Osterman, Eric Burgh, Matthew Beasley, Paul Scowen, Todd Veach, Steven Jordan, Dennis Ebbets, Michael Lieber, James DeCino, Bruno Vaz Castilho, Clemens Gneiding, Antonio César De Oliveira

Research output: Chapter in Book/Report/Conference proceedingConference contribution

1 Citation (Scopus)

Abstract

We present a conceptual design for a high-resolution optical spectrograph appropriate for mounting at Cassegrain on a large aperture telescope. The design is based on our work for the Gemini High Resolution Optical Spectrograph (CUGHOS) project. Our design places the spectrograph at Cassegrain focus to maximize throughput and blue wavelength coverage, delivering R=40,000 resolving power over a continuous 320-1050 nm waveband with throughputs twice those of current instruments. The optical design uses a two-arm, cross-dispersed echelle format with each arm optimized to maximize efficiency. A fixed image slicer is used to minimize optics sizes. The principal challenge for the instrument design is to minimize flexure and degradation of the optical image. To ensure image stability, our opto-mechanical design combines a cost-effective, passively stable bench employing a honeycomb aluminum structure with active flexure control. The active flexure compensation consists of hexapod mounts for each focal plane with full 6-axis range of motion capability to correct for focus and beam displacement. We verified instrument performance using an integrated model that couples the optical and mechanical design to image performance. The full end-to-end modeling of the system under gravitational, thermal, and vibrational perturbations shows that deflections of the optical beam at the focal plane are <29 μm per exposure under the worst case scenario (<10 μm for most orientations), with final correction to 5 μm or better using open-loop active control to meet the stability requirement. The design elements and high fidelity modeling process are generally applicable to instruments requiring high stability under a varying gravity vector.

Original languageEnglish (US)
Title of host publicationOptomechanical Engineering 2013
Volume8836
DOIs
StatePublished - Dec 1 2013
EventOptomechanical Engineering 2013 - San Diego, CA, United States
Duration: Aug 26 2013Aug 29 2013

Other

OtherOptomechanical Engineering 2013
CountryUnited States
CitySan Diego, CA
Period8/26/138/29/13

Fingerprint

Spectrographs
Conceptual Design
Spectrograph
Conceptual design
Telescopes
spectrographs
Flexure
Telescope
High Resolution
apertures
telescopes
Mechanical Design
high resolution
Optical Design
Focal Plane
flexing
Throughput
Maximise
Hexapod
Echelle

Keywords

  • Cassegrain mount
  • flexure control
  • integrated modeling
  • Optical spectroscopy

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering

Cite this

Froning, C. S., Osterman, S., Burgh, E., Beasley, M., Scowen, P., Veach, T., ... César De Oliveira, A. (2013). A conceptual design for a Cassegrain-mounted high-resolution optical spectrograph for large-aperture telescopes. In Optomechanical Engineering 2013 (Vol. 8836). [88360Y] https://doi.org/10.1117/12.2024056

A conceptual design for a Cassegrain-mounted high-resolution optical spectrograph for large-aperture telescopes. / Froning, Cynthia S.; Osterman, Steven; Burgh, Eric; Beasley, Matthew; Scowen, Paul; Veach, Todd; Jordan, Steven; Ebbets, Dennis; Lieber, Michael; DeCino, James; Castilho, Bruno Vaz; Gneiding, Clemens; César De Oliveira, Antonio.

Optomechanical Engineering 2013. Vol. 8836 2013. 88360Y.

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Froning, CS, Osterman, S, Burgh, E, Beasley, M, Scowen, P, Veach, T, Jordan, S, Ebbets, D, Lieber, M, DeCino, J, Castilho, BV, Gneiding, C & César De Oliveira, A 2013, A conceptual design for a Cassegrain-mounted high-resolution optical spectrograph for large-aperture telescopes. in Optomechanical Engineering 2013. vol. 8836, 88360Y, Optomechanical Engineering 2013, San Diego, CA, United States, 8/26/13. https://doi.org/10.1117/12.2024056
Froning CS, Osterman S, Burgh E, Beasley M, Scowen P, Veach T et al. A conceptual design for a Cassegrain-mounted high-resolution optical spectrograph for large-aperture telescopes. In Optomechanical Engineering 2013. Vol. 8836. 2013. 88360Y https://doi.org/10.1117/12.2024056
Froning, Cynthia S. ; Osterman, Steven ; Burgh, Eric ; Beasley, Matthew ; Scowen, Paul ; Veach, Todd ; Jordan, Steven ; Ebbets, Dennis ; Lieber, Michael ; DeCino, James ; Castilho, Bruno Vaz ; Gneiding, Clemens ; César De Oliveira, Antonio. / A conceptual design for a Cassegrain-mounted high-resolution optical spectrograph for large-aperture telescopes. Optomechanical Engineering 2013. Vol. 8836 2013.
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