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Session 21 - Amateurs & Professionals: Collaborators in the New Age of Electronic Astronomy - I.
Oral session, Tuesday, June 10
North Main Hall C/D,
The traditional method of measuring double star distances and position angles with a filar micrometer is so arduous to do properly that few amateur astronomers participate in this work. However, now that CCD cameras are widely used in the amateur astronomy community, it was reasonable to ask, with their superior dimensional and photometric sensitivity, if they could be used for accurate measurements of faint double stars with small telescopes. With the short exposures (normally 0.1 to 0.8 seconds for primaries up to 9th magnitude) available with commercial CCDs, the images show consistent speckle scintillation patterns rather than the completely smeared gaussians of conventional longer exposure photographs. It is possible to sort through a series of these exposures and identify those where the brightest speckle is also at a frame-to-frame stable position. On the reasonable assumption that such a speckle represents the central location of each star, highly accurate measurements of faint pairs can be obtained in an efficient way. These measurements are made away from the telescope and with proper attention to instrument calibration and astrometric details can yield information that appears to be comparable to traditional micrometer measurements. An initial survey of nearly 100 pairs showed nine that had linear proper motion and one that may have orbital motion.
