Software Bisque Knowledge Base Article – 1209

THESKY6 AND CCDSOFT REPORT DIFFERENT POSITION ANGLES FOR IMAGES

ISSUE

TheSky6’s Image Link position angle does not equal CCDSoft’s AutoAstrometry position angle. Why?

Position angle reported by TheSky6’s Image Link Information

Position angle reported by CCDSoft’s Insert WCS/AutoAstrometry command.

RESOLUTION

TheSky6 and CCDSoft use a different convention to measure position angle. TheSky6’s Image Link measures the position angle counterclockwise from north. CCDSoft’s Source Extractor algorithms measure position angle clockwise from north.

To convert TheSky6’s Image Link position angle to CCDSoft’s AutoAstrometry:

CCDSoft’s position angle = 360 – TheSky6’s position angle

APPLIES TO

TheSky6 Professional Edition and CCDSoft Version 5.00.159 and earlier. Later versions of CCDSoft do not exhibit this behavior.

KEYWORDS

SBKB

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