Multispectral analysis of the Night Sky Brightness at Oukaimeden Observatory, Morocco
Bibliographic record
Abstract
ABSTRACT We modelled night sky brightness (NSB) over the Oukaimeden region south-east of Marrakesh, where the Oukaimeden Observatory of Cadi Ayyad University (OUCA) is located.The simulations were performed using the newest version of ILLUMINA (V2.2), which is an advanced heterogeneous artificial sky brightness model designed to predict the spectral contribution of artificial lighting to the NSB. This model requires specific ground-based data, including photometric and spectroscopic properties of various light fixture types (light-emitting diodes and high-pressure Sodium) present in both the Marrakesh and Oukaimeden regions. In this paper, we report the first quantitative assessment of the impact of artificial light on astronomical observations at this high-altitude facility (OUCA), along with a comparative analysis of the current state of the NSB in the Johnson B and V bands. In addition, we present some results of this study by using the Natural Sky Unit (NSU) scale, which provides an intuitive measure of sky brightness relative to it’s natural brightness. For the OUCA, the NSU scale showed slightly variation over most of the sky, ranging from 1 NSU to 1.6 NSU over the B and V bands, indicating a minimal effect of light pollution. Whereas, we found that the city of Marrakesh and the village of Ourika, are the primary contributors to light pollution at OUCA, particularly affecting observations in both spectral bands (B and V) at low elevation angles between $0^{\circ }$ and $35^{\circ }$. The findings of this study align with global efforts to preserve dark skies and natural nocturnal environments.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot 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.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.001 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
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.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
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".