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Record W1982611976 · doi:10.1086/517619

Image Quality of Liquid‐Mirror Telescopes

2007· article· en· W1982611976 on OpenAlexaff
Paul Hickson, Réne Racine

Bibliographic record

VenuePublications of the Astronomical Society of the Pacific · 2007
Typearticle
Languageen
FieldPhysics and Astronomy
TopicAdaptive optics and wavefront sensing
Canadian institutionsUniversité de MontréalUniversité du Québec à MontréalUniversity of British Columbia
Fundersnot available
KeywordsTelescopePhysicsOpticsZenithObservatoryWavelengthImage qualityPoint spread functionRemote sensingAstrophysicsGeologyImage (mathematics)

Abstract

fetched live from OpenAlex

The quality of astronomical images obtained with the 3 m liquid‐mirror telescope (LMT) of the NASA Orbital Debris Observatory (NODO) and with the University of British Columbia 6 m Large Zenith Telescope (LZT) is assessed and compared to that of conventional instruments. Analysis of star images in long‐exposure drift‐scan data indicates that the profile of the image core is primarily set by atmospheric turbulence. Defocused star images reveal the presence of low‐amplitude waves on the surface of the mercury, also seen in laboratory tests. The effect of these waves is to diffract light into the wings of the point‐spread function. Analysis of the intensity profiles of stellar images can therefore probe the structure of the mirror surface on scales smaller than the atmospheric coherence length, which is about an order of magnitude larger that the characteristic wavelengths of the surface waves. It is found that the rms surface height error produced by these waves was approximately 37 nm for the NODO LMT. Improvements to the rotational speed stability of liquid mirrors, reduction of the thickness of the mercury layer, and use of a protective Mylar cover have allowed the LZT to reduce this source of error to approximately 9 nm rms, thereby achieving an image quality approaching that of conventional telescopes.

Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.

How this classification was reachedexpand

Full frame machine prediction

Teacher imitation

Not calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.

metaresearch head score (Codex)0.001
metaresearch head score (Gemma)0.008
Version: metacan-v3-hybrid-931329e0061cValidation status: machine_predicted_unvalidated
Candidate categoriesnone
Consensus categoriesnone
DomainCandidate signal: none · Consensus signal: none
Study designCandidate signal: Bench or experimental · Consensus signal: Bench or experimental
GenreCandidate signal: Empirical · Consensus signal: Empirical
Teacher disagreement score0.003
Threshold uncertainty score0.011

Distilled classifier scores by category (both heads)

CategoryCodexGemma
Metaresearch0.0010.008
Meta-epidemiology (narrow)0.0000.000
Meta-epidemiology (broad)0.0000.000
Bibliometrics0.0010.001
Science and technology studies0.0000.000
Scholarly communication0.0010.001
Open science0.0010.001
Research integrity0.0010.000
Insufficient payload (model declined to judge)0.0030.001

Machine scores (provisional)

The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.

Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.

Opus teacher head0.023
GPT teacher head0.276
Teacher spread0.254 · how far apart the two teachers sit on this one work
Validation statusscore_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from it

Classification

machine, unvalidated

Machine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.

The models applied no category: nothing in the taxonomy fit this work.
Study designBench or experimental
Domainnot available
GenreEmpirical

How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".

Quick stats

Citations20
Published2007
Admission routes1
Has abstractyes

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Same venuePublications of the Astronomical Society of the PacificSame topicAdaptive optics and wavefront sensingFrench-language works237,207