Bibliographic record
Abstract
This paper analyzes a compilation of aperture diameters D and commissioning dates t for 177 optical telescopes, including those that have been among the largest of their time. We offer the following findings, and draw the following inferences, about aperture growth D ( t ) over four centuries: 1. From the days of Galileo to the present, telescope diameters have steadily grown, with a doubling time t 2 × of nearly 50 yr. 2. Beginning in 1730, major refractors' apertures followed a strictly exponential curve of growth, with t 2 × = 45 yr, before stopping with the Yerkes 40 inch (1.02 m) in 1897. 3. Over the last 300 yr, the very largest "frontier" reflectors have defined a sharp and distinct upper boundary to the D ( t ) distribution, with t 2 × = 48 yr and D 1900 = 2.3 m. This exponential growth is taken to have been imposed strictly by the rate at which telescope technology has progressed. 4. Data for second‐tier "large" reflectors yield D 1900 = 1.0 m and t 2 × = 47 yr until 1950 and suggest an exponential decrease of the doubling time afterwards, e ‐folding in ∼70 yr and leading to t 2 × = 20 yr in 2000. This may be the result of a gradual relief, through increased collaboration, of constraints that prevented the limits of technology from being reached. 5. The curves of growth for large and for frontier reflectors cross in ∼2010. Whether the aperture growth in the 21st century is limited by demographics—collaborations—or by technology remains to be seen. 6. During the 20th century, commissioning of large telescopes tended to occur in bursts at ∼35 yr intervals. 7. Giant telescopes with serious shortcomings were not uncommon before 1850. These typically had twice the aperture of their more productive contemporaries. 8. The completion of the current burst of ambitiously large 20–100 m telescope projects with the scheduled launch of the James Webb Space Telescope in the 2010s would constitute a dramatic break with 4 centuries of historical evolution.
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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 | 0.004 | 0.022 |
| Meta-epidemiology (narrow) | 0.000 | 0.001 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.003 | 0.004 |
| Science and technology studies | 0.001 | 0.003 |
| Scholarly communication | 0.003 | 0.004 |
| Open science | 0.000 | 0.002 |
| Research integrity | 0.001 | 0.002 |
| Insufficient payload (model declined to judge) | 0.002 | 0.001 |
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.
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".