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Microspots on IIIa-J Plates (“Gold Spot Disease”)

Published online by Cambridge University Press:  12 April 2016

M. Elizabeth Sim
M. Elizabeth Sim*
Affiliation:
UK Schmidt Telescope Unit, Royal Observatory, Edinburgh EH9 3HJ, UK

Extract

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The UK 1.2 metre Schmidt Telescope at Siding Spring Observatory, Australia, has taken about 8500 plates since it was commissioned in 1973. A large fraction of these plates, including those for the southern and equatorial Sky Surveys, are on Eastman Kodak Illa-J emulsion. A significant number of these processed Illa-J plates have developed many small gold spots similar in size to faint star images. They are most likely to occur in areas of relatively high density, such as in bright star images or on the stepwedges, and are sometimes scattered around in non-image areas (fig. 1). An alarmingly high proportion of plates taken in 1974-75 (about 50 per cent) have developed gold spots, and the most recent affected plate found so far is J6517, taken in October 1980. Four early IIIa-F plates have also been found to have gold spots.

Type
Research Article
Information
International Astronomical Union Colloquium , Volume 78: Astronomy with Schmidt-type telescopes , 1984 , pp. 143 - 145
Copyright
Copyright © Reidel 1984

References

1. Millikan, P.G., Miller, W.J., and Black, D.L. “Astronomical Photography 81”, ed. Heudier, & Sim, , p. 153, 1981.Google Scholar
2. Feldman, L.H., Jnl Applied Photographie Engineering 7, 1, 1982.Google Scholar