ASTROMETRY.NET: BLIND ASTROMETRIC CALIBRATION OF ARBITRARY ASTRONOMICAL IMAGES

By Dustin Lang, David W. Hogg, Keir Mierle, M. Blanton, Sam T. Roweis. 2009

932 citations recorded by the source corpus.

We have built a reliable and robust system that takes as input an astronomical image, and returns as output the pointing, scale, and orientation of that image (the astrometric calibration or World Coordinate System information). The system requires no first guess, and works with the information in the image pixels alone; that is, the problem is a generalization of the “lost in space” problem in which nothing—not even the image scale—is known. After robust source detection is performed in the input image, asterisms (sets of four or five stars) are geometrically hashed and compared to pre-indexed hashes to generate hypotheses about the astrometric calibration. A hypothesis is only accepted as true if it passes a Bayesian decision theory test against a null hypothesis. With indices built from the USNO-B catalog and designed for uniformity of coverage and redundancy, the success rate is >99.9% for contemporary near-ultraviolet and visual imaging survey data, with no false positives. The failure rate is consistent with the incompleteness of the USNO-B catalog; augmentation with indices built from the Two Micron All Sky Survey catalog brings the completeness to 100% with no false positives. We are using this system to generate consistent and standards-compliant meta-data for digital and digitized imaging from plate repositories, automated observatories, individual scientific investigators, and hobbyists. This is the first step in a program of making it possible to trust calibration meta-data for astronomical data of arbitrary provenance.

Subfields: Astronomy and Astrophysics, Computational Mechanics

View Paper: https://www.semanticscholar.org/paper/9fde11ea9cc41db74b698cd42d11f12a43d2d093

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Citations in the corpus

HATSouth: A Global Network of Fully Automated Identical Wide-Field Telescopes (2012, methodology): “Should this astrometry fail, we fall back on using astrometry.net (Lang et al. 2010), which can produce a robust (but less accurate) solution even for very large pointing errors.”
The All-Sky Automated Survey for Supernovae (ASAS-SN) Light Curve Server v1.0 (2017, methodology): “This research has made use of data provided by Astrometry.net (Lang et al. 2010).”
The ATLAS All-Sky Stellar Reference Catalog (2018, methodology): “A subset of these stars is matched to sky positions using code from astrometry. net (Lang et al. 2010) to obtain an initial astrometric solution.”
ASTROIMAGEJ: IMAGE PROCESSING AND PHOTOMETRIC EXTRACTION FOR ULTRA-PRECISE ASTRONOMICAL LIGHT CURVES (2016, neutral): “Astrometry/Plate Solving The astrometry feature “plate solves” images using an internet connection to the astrometry.net web portal at nova.astrometry.net(Lang et al. 2010).”
J-GEM observations of an electromagnetic counterpart to the neutron star merger GW170817 (2017, methodology): “The astrometric calibrations were performed with astrometry.net (Lang et al. 2010) using the default reference catalog USNO-B1.”
ATLAS: A High-cadence All-sky Survey System (2018, background): “…save to disk as a raw image 40 80 Flatten image 500 250 Measure the brightest ∼60,000 stars (dophot) 20 270 Find initial astrometric solution (Lang et al. 2010) 10 280 Determine final astrometric and photometric solution 20 300 Perform cloud detection and correction 10 310 Calculate…”
Mapping stellar content to dark matter haloes using galaxy clustering and galaxy–galaxy lensing in the SDSS DR7 (2015, methodology): “For each given galaxy, we find all the neighbouring galaxies within a cylinder of radius rmaxp and height 2rmaxπ centered on that galaxy, using the libkd package within the Astrometry.net software (Lang et al. 2010).”
The SED Machine: A Robotic Spectrograph for Fast Transient Classification (2017, methodology): “However, as a first step, the pipeline runs Astrometry.net (Lang et al. 2010) on the complete raw image in order to obtain a WCS solution using all filters at the same time.”