Ms. LeEllen Phelps Profile

LeEllen Phelps

at National Solar Observatory

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Author

Publications (19)

Proceedings Article | 10 July 2018 Paper

Factory acceptance testing and model refinement for the Daniel K. Inouye Solar Telescope air knife assembly

Isaac McQuillen, LeEllen Phelps

Proceedings Volume 10705, 1070525 (2018) https://doi.org/10.1117/12.2314097

KEYWORDS: Fluctuations and noise, Wavefronts, Space telescopes, Telescopes, Visualization, Interfaces, Error analysis, Solar telescopes, Computational fluid dynamics, Hardware testing, Cleanroom equipment

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Proceedings Article | 22 August 2016 Paper

Daniel K. Inouye Solar Telescope: computational fluid dynamic analyses and evaluation of the air knife model

Isaac McQuillen, LeEllen Phelps, Mark Warner, Robert Hubbard

Proceedings Volume 9911, 99111M (2016) https://doi.org/10.1117/12.2231891

KEYWORDS: CFD analysis, Curtains, Interfaces, Protactinium, Error analysis, Solar telescopes, Wavefronts, Space telescopes, Fluctuations and noise, Thermal modeling

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Implementation of an air curtain at the thermal boundary between conditioned and ambient spaces allows for observation over wavelength ranges not practical when using optical glass as a window. The air knife model of the Daniel K. Inouye Solar Telescope (DKIST) project, a 4-meter solar observatory that will be built on Haleakalā, Hawai’i, deploys such an air curtain while also supplying ventilation through the ceiling of the coudé laboratory. The findings of computational fluid dynamics (CFD) analysis and subsequent changes to the air knife model are presented. Major design constraints include adherence to the Interface Control Document (ICD), separation of ambient and conditioned air, unidirectional outflow into the coudé laboratory, integration of a deployable glass window, and maintenance and accessibility requirements. Optimized design of the air knife successfully holds full 12 Pa backpressure under temperature gradients of up to 20°C while maintaining unidirectional outflow. This is a significant improvement upon the .25 Pa pressure differential that the initial configuration, tested by Linden and Phelps, indicated the curtain could hold. CFD post- processing, developed by Vogiatzis, is validated against interferometry results of initial air knife seeing evaluation, performed by Hubbard and Schoening. This is done by developing a CFD simulation of the initial experiment and using Vogiatzis’ method to calculate error introduced along the optical path. Seeing error, for both temperature differentials tested in the initial experiment, match well with seeing results obtained from the CFD analysis and thus validate the post-processing model. Application of this model to the realizable air knife assembly yields seeing errors that are well within the error budget under which the air knife interface falls, even with a temperature differential of 20°C between laboratory and ambient spaces. With ambient temperature set to 0°C and conditioned temperature set to 20°C, representing the worst-case temperature gradient, the spatial rms wavefront error in units of wavelength is 0.178 (88.69 nm at λ = 500 nm).

Proceedings Article | 18 August 2016 Paper

Construction status of the Daniel K. Inouye solar telescope

Joseph McMullin, Thomas Rimmele, Mark Warner, Valentin Pillet, Roberto Casini, Steve Berukoff, Simon Craig, David Elmore, Andrew Ferayorni, Bret Goodrich, Robert Hubbard, David Harrington, Steve Hegwer, Paul Jeffers, Erik Johansson, Jeff Kuhn, Haosheng Lin, Heather Marshall, Mihalis Mathioudakis, William McBride, William McVeigh, LeEllen Phelps, Wolfgang Schmidt, Steve Shimko, Stacey Sueoka, Alexandra Tritschler, Timothy Williams, Friedrich Wöger

Proceedings Volume 9906, 99061B (2016) https://doi.org/10.1117/12.2235227

KEYWORDS: Imaging systems, Observatories, Solar processes, Telescopes, Mirrors, Optical fabrication, Buildings, Space telescopes, Control systems, Deformable mirrors

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We provide an update on the construction status of the Daniel K. Inouye Solar Telescope. This 4-m diameter facility is designed to enable detection and spatial/temporal resolution of the predicted, fundamental astrophysical processes driving solar magnetism at their intrinsic scales throughout the solar atmosphere. These data will drive key research on solar magnetism and its influence on solar winds, flares, coronal mass ejections and solar irradiance variability. The facility is developed to support a broad wavelength range (0.35 to 28 microns) and will employ state-of-the-art adaptive optics systems to provide diffraction limited imaging, resolving features approximately 20 km on the Sun. At the start of operations, there will be five instruments initially deployed: Visible Broadband Imager (VBI; National Solar Observatory), Visible SpectroPolarimeter (ViSP; NCAR High Altitude Observatory), Visible Tunable Filter (VTF (a Fabry-Perot tunable spectropolarimeter); Kiepenheuer Institute for Solarphysics), Diffraction Limited NIR Spectropolarimeter (DL-NIRSP; University of Hawaii, Institute for Astronomy) and the Cryogenic NIR Spectropolarimeter (Cryo-NIRSP; University of Hawaii, Institute for Astronomy).

As of mid-2016, the project construction is in its 4th year of site construction and 7th year overall. Major milestones in the off-site development include the conclusion of the polishing of the M1 mirror by University of Arizona, College of Optical Sciences, the delivery of the Top End Optical Assembly (L3), the acceptance of the Deformable Mirror System (Xinetics); all optical systems have been contracted and are either accepted or in fabrication. The Enclosure and Telescope Mount Assembly passed through their factory acceptance in 2014 and 2015, respectively. The enclosure site construction is currently concluding while the Telescope Mount Assembly site erection is underway. The facility buildings (Utility and Support and Operations) have been completed with ongoing work on the thermal systems to support the challenging imaging requirements needed for the solar research.

Finally, we present the construction phase performance (schedule, budget) with projections for the start of early operations.

Proceedings Article | 9 August 2016 Paper

Cooling a solar telescope enclosure: plate coil thermal analysis

Michael Gorman, Chriselle Galapon, Guillermo Montijo, LeEllen Phelps, Gaizka Murga

Proceedings Volume 9911, 99111U (2016) https://doi.org/10.1117/12.2232160

KEYWORDS: Solar telescopes, Observatories, Telescopes, Thermal analysis, Systems modeling, Solar radiation models, Cooling systems, Data modeling, Solar radiation, MATLAB

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The climate of Haleakalā requires the observatories to actively adapt to changing conditions in order to produce the best possible images. Observatories need to be maintained at a temperature closely matching ambient or the images become blurred and unusable. The Daniel K. Inouye Solar Telescope is a unique telescope as it will be active during the day as opposed to the other night-time stellar observatories. This means that it will not only need to constantly match the ever-changing temperature during the day, but also during the night so as not to sub-cool and affect the view field of other telescopes while they are in use.

To accomplish this task, plate coil heat exchanger panels will be installed on the DKIST enclosure that are designed to keep the temperature at ambient temperature +0°C/-4°C. To verify the feasibility of this and to validate the design models, a test rig has been installed at the summit of Haleakalā. The project’s purpose is to confirm that the plate coil panels are capable of maintaining this temperature throughout all seasons and involved collecting data sets of various variables including pressures, temperatures, coolant flows, solar radiations and wind velocities during typical operating hours. Using MATLAB, a script was written to observe the plate coil’s thermal performance. The plate coil did not perform as expected, achieving a surface temperature that was generally 2ºC above ambient temperature. This isn’t to say that the plate coil does not work, but the small chiller used for the experiment was undersized resulting in coolant pumped through the plate coil that was not supplied at a low enough temperature. Calculated heat depositions were about 23% lower than that used as the basis of the design for the hillers to be used on the full system, a reasonable agreement given the fact that many simplifying assumptions were used in the models. These were not carried over into the testing.

The test rig performance showing a 23% margin provides a high degree of confidence for the performance of the full system when it is installed. If time allows, additional testing could be done that includes additional incident angles and times of day. This would allow a more complete analysis. If additional testing were to be performed, it’s recommended to use a larger chiller capable of reaching lower temperatures. The test rig design could also be optimized in order to bring the plate coil up to its maximum efficiency. In the future, the script could be rewritten in a different computer language, so that the data could be solved for quicker. Further analysis could also include different types of coolants.

Proceedings Article | 8 August 2016 Paper

Project management and control of the Daniel K. Inouye Solar Telescope

Joseph McMullin, William McVeigh, Mark Warner, Thomas Rimmele, Simon Craig, Andrew Ferayorni, Bret Goodrich, Robert Hubbard, Rex Hunter, Paul Jeffers, Erik Johansson, Heather Marshall, William McBride, LeEllen Phelps, Steve Shimko, Alexandra Tritschler, Timothy Williams, Friedrich Wöger

Proceedings Volume 9911, 99110K (2016) https://doi.org/10.1117/12.2235225

KEYWORDS: Solar telescopes, Systems engineering, Observatories, Content addressable memory, Chromium, Control systems, Neodymium, Databases, Phase modulation, Process control

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Proceedings Article | 27 July 2016 Paper

DKIST facility management system integration

Charles White, LeEllen Phelps

Proceedings Volume 9906, 990652 (2016) https://doi.org/10.1117/12.2233118

KEYWORDS: Solar telescopes, Control systems, System integration, Fourier transforms, Cooling systems, Telescopes, Fermium, Frequency modulation, Fluorescence correlation spectroscopy, Fluctuations and noise

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Proceedings Article | 4 August 2014 Paper

Plate coil thermal test bench for the Daniel K. Inouye Solar Telescope (DKIST) carousel cooling system

LeEllen Phelps, Gaizka Murga, Guillermo Montijo, David Hauth

Proceedings Volume 9150, 91501Q (2014) https://doi.org/10.1117/12.2057029

KEYWORDS: Solar radiation models, Cooling systems, Systems modeling, Thermal modeling, Solar telescopes, Control systems, Cladding, Atmospheric modeling, Safety, Data modeling

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Proceedings Article | 17 September 2012 Paper

Behavior of a horizontal air curtain subjected to a vertical pressure gradient

James Linden, LeEllen Phelps

Proceedings Volume 8444, 84443S (2012) https://doi.org/10.1117/12.925498

KEYWORDS: Curtains, Protactinium, Adaptive optics, Telescopes, Observatories, Space telescopes, Fluctuations and noise, Solar telescopes, Interfaces, Wavefront distortions

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Proceedings Article | 17 September 2012 Paper

Facility level thermal systems for the Advanced Technology Solar Telescope

LeEllen Phelps, Gaizka Murga, Mark Fraser, Tània Climent

Proceedings Volume 8444, 84443M (2012) https://doi.org/10.1117/12.924592

KEYWORDS: Telescopes, Control systems, Computing systems, Fluctuations and noise, Cooling systems, Wind energy, Energy efficiency, Solar telescopes, Space telescopes, Coating

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Proceedings Article | 10 November 2011 Paper

ATST enclosure mechanical and thermal models

Gaizka Murga, Heather Marshall, LeEllen Phelps, Ana Hervás, Ibon Larracoechea

Proceedings Volume 8336, 83360K (2011) https://doi.org/10.1117/12.915575

KEYWORDS: Camera shutters, Solar radiation models, Telescopes, Thermal modeling, Control systems, Systems modeling, Solar telescopes, Observatories, Sun, Skin

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Proceedings Article | 7 August 2010 Paper

The Advanced Technology Solar Telescope coude lab thermal environment

LeEllen Phelps, Thomas Rimmele, Robert Hubbard, David Elmore

Proceedings Volume 7733, 77333U (2010) https://doi.org/10.1117/12.856012

KEYWORDS: Humidity, Space telescopes, Solar telescopes, Particles, Telescopes, Ions, Computing systems, Control systems, Neodymium, Curtains

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Proceedings Article | 28 July 2010 Paper

The Advanced Technology Solar Telescope: beginning construction of the world's largest solar telescope

T. R. Rimmele, J. Wagner, S. Keil, D. Elmore, R. Hubbard, E. Hansen, M. Warner, P. Jeffers, L. Phelps, H. Marshall, B. Goodrich, K. Richards, S. Hegwer, R. Kneale, J. Ditsler

Proceedings Volume 7733, 77330G (2010) https://doi.org/10.1117/12.857714

KEYWORDS: Control systems, Telescopes, Adaptive optics, Wavefronts, Solar processes, Solar telescopes, Mirrors, Cameras, Interfaces, Observatories

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Proceedings Article | 10 July 2008 Paper

Advanced Technology Solar Telescope M1 thermal control system design, modeling, and prototype testing

Eric Hansen, Scott Bulau, LeEllen Phelps

Proceedings Volume 7012, 701233 (2008) https://doi.org/10.1117/12.787600

KEYWORDS: Mirrors, Prototyping, Thermal modeling, Control systems design, Solar telescopes, Performance modeling, Convection, Observatories, Telescopes, Control systems

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Proceedings Article | 10 July 2008 Paper

Advanced Technology Solar Telescope: a progress report

J. Wagner, T. Rimmele, S. Keil, R. Hubbard, E. Hansen, L. Phelps, M. Warner, B. Goodrich, K. Richards, S. Hegwer, R. Kneale, J. Ditsler

Proceedings Volume 7012, 70120I (2008) https://doi.org/10.1117/12.789436

KEYWORDS: Telescopes, Control systems, Wavefronts, Adaptive optics, Observatories, Mirrors, Buildings, Control systems design, Solar telescopes, Optical instrument design

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Proceedings Article | 10 July 2008 Paper

Evaluation of thermal control coatings exposed to ambient weather conditions at Haleakala High Altitude Observatory

L. Phelps

Proceedings Volume 7012, 701230 (2008) https://doi.org/10.1117/12.789156

KEYWORDS: Reflectivity, Observatories, Manufacturing, Thin film coatings, Photography, Thermal modeling, Cements, Solar telescopes, Ceramics, Visualization

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Proceedings Article | 9 July 2008 Paper

Advanced Technology Solar Telescope lower enclosure thermal system

L. Phelps, M. Warner

Proceedings Volume 7017, 701719 (2008) https://doi.org/10.1117/12.789340

KEYWORDS: Sun, Solar telescopes, Fluctuations and noise, Observatories, Thermal modeling, Control systems, Particles, Performance modeling, Skin, Atmospheric optics

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Proceedings Article | 26 June 2006 Paper

The Advanced Technology Solar Telescope enclosure

L. Phelps, J. Barr, N. Dalrymple, M. Fraser, R. Hubbard, J. Wagner, M. Warner

Proceedings Volume 6267, 62673E (2006) https://doi.org/10.1117/12.672167

KEYWORDS: Thermal modeling, Telescopes, Systems modeling, Convection, Solar radiation models, Solar telescopes, Cooling systems, Control systems, Camera shutters, Observatories

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Proceedings Article | 23 June 2006 Paper

Advanced Technology Solar Telescope: a progress report

J. Wagner, T. Rimmele, S. Keil, J. Barr, N. Dalrymple, J. Ditsler, B. Goodrich, E. Hansen, S. Hegwer, F. Hill, R. Hubbard, L. Phelps, R. Price, K. Richards, M. Warner

Proceedings Volume 6267, 626709 (2006) https://doi.org/10.1117/12.672495

KEYWORDS: Telescopes, Control systems, Mirrors, Wavefronts, Adaptive optics, Observatories, Control systems design, Buildings, Interfaces, Solar telescopes

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Proceedings Article | 15 September 2005 Paper

Advanced Technology Solar Telescope: a progress report

T. Rimmele, S. Keil, J. Wagner, N. Dalrymple, B. Goodrich, E. Hansen, F. Hill, R. Hubbard, L. Phelps, K. Richards, M. Warner

Proceedings Volume 5901, 590104 (2005) https://doi.org/10.1117/12.618354

KEYWORDS: Telescopes, Mirrors, Control systems, Adaptive optics, Solar telescopes, Wavefronts, Wavefront sensors, Interfaces, Observatories, Visible radiation

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Showing 5 of 19 publications

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