# On the nature of apparent transient sources on the National Geographic Society-Palomar Observatory Sky Survey glass copy plates

Source: [On the nature of apparent transient sources on the National Geographic Society-Palomar Observatory Sky Survey glass copy plates](<https://www.sota2.com/research/paper/68fa469b1e209131ce921950>)

Collection index: [llms.txt](<https://www.sota2.com/research/llms.txt>)

Data updated: 2025-10-25T05:54:05.097Z

Authors: Nigel Hambly, Adam Blair

Published: 2024-02-01T11:06:49.000Z

## Abstract

We examine critically recent claims for the presence of above-atmosphere optical transients in publicly-available digitised scans of Schmidt telescope photographic plate material derived from the National Geographic Society-Palomar Observatory Sky Survey. We employ the publicly available SuperCOSMOS Sky Survey catalogues to examine statistically the morphology of the sources. We develop a simple, objective and automated image classification scheme based on a random forest decision tree classifier. We find that the putative transients are likely to be spurious artefacts of the photographic emulsion. We suggest a possible cause of the appearance of these images as resulting from the copying procedure employed to disseminate glass copy survey atlas sets in the era before large-scale digitisation programmes.

## Recorded benchmark results

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## Original sources and implementation

[Original paper](<https://arxiv.org/abs/2402.00497>)

[PDF](<https://arxiv.org/pdf/2402.00497.pdf>)