English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

Astrometric calibration is based on patterns of cataloged stars and thereforeeffectively assumes a particular epoch, which can be substantially incorrectfor historical images. With the known proper motions of stars we can "run backthe clock" to an approximation of the night sky in any given year, and inprinciple the year that best fits stellar patterns in any given image is anestimate of the year in which that image was taken. In this paper we use 47scanned photographic images of M44 spanning years 1910-1975 to demonstrate thistechnique. We use only the pixel information in the images; we use no priorinformation or meta-data about image pointing, scale, orientation, or date.Blind Date returns date meta-data for the input images. It also improves theastrometric calibration of the image because the final astrometric calibrationis performed at the appropriate epoch. The accuracy and reliability of BlindDate are functions of image size, pointing, angular resolution, and depth;performance is related to the sum of proper-motion signal-to-noise ratios forcatalog stars measured in the input image. All of the science-quality imagesand 85 percent of the low-quality images in our sample of photographic plateimages of M44 have their dates reliably determined to within a decade, many towithin months.

Blind Date: Using proper motions to determine the ages of historical images