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

We compared several techniques for calibrating angular separation betweenwide (>1 arcsec) pairs. These techniques are (i) reference pair calibrationusing {\alpha} Cen AB orbital parameters, (ii) the video drift method, and(iii) the utilisation of an aperture diffraction grating with red filters ofdifferent passbands. Separations of 62 pairs were determined using these 3calibration techniques and compared. It was found that {\alpha} Cen AB andvideo drift methods are in good agreement.  The use of the grating and filter (by measuring fringe spacing) provedunsatisfactory for the broad-band filters, and the use of a narrow bandH{\alpha} filter with the grating, resulted in image scales that differed fromthose obtained using {\alpha} Cen AB reference pair calibration and the videodrift method by 0.024 and 0.031 pixel/arcsec (px/arcsec) respectively. A morecomplete modelling of Fraunhofer diffraction of the H{\alpha} filter andgrating produced a difference in image scale of 0.009 px/arcsec.  A bias in the diffraction grating method of ~0.1% in the separation of pairsalso revealed itself and could not be accounted for. We conclude thatcalibration against a known pair for which the separation and PA is known withhigh precision is probably the simplest and best way to undertake image scalecalibration.

Comparison of Image Scale Calibration Techniques: Known Pairs, Drift Scans and Aperture Grating