AstroPT: Scaling Large Observation Models for Astronomy
This work addresses the need for open-source large-scale models in observational sciences like astronomy, though it is incremental as it applies existing transformer methods to new astronomical data.
The authors tackled the problem of scaling large observation models for astronomy by developing AstroPT, an autoregressive pretrained transformer trained on 8.6 million galaxy images, and found that it follows a saturating scaling law with performance improving up to 2.1 billion parameters.
This work presents AstroPT, an autoregressive pretrained transformer developed with astronomical use-cases in mind. The AstroPT models presented here have been pretrained on 8.6 million $512 \times 512$ pixel $grz$-band galaxy postage stamp observations from the DESI Legacy Survey DR8. We train a selection of foundation models of increasing size from 1 million to 2.1 billion parameters, and find that AstroPT follows a similar saturating log-log scaling law to textual models. We also find that the models' performances on downstream tasks as measured by linear probing improves with model size up to the model parameter saturation point. We believe that collaborative community development paves the best route towards realising an open source `Large Observation Model' -- a model trained on data taken from the observational sciences at the scale seen in natural language processing. To this end, we release the source code, weights, and dataset for AstroPT under the MIT license, and invite potential collaborators to join us in collectively building and researching these models.