Background and first results from the new AAO/UKST H survey

Preliminary H image comparisons

An impression of the significant information gains from the new Tech Pan H filter combination compared to previous UKST H imaging is presented in figure 2a-d. The figures show an identical arcminute area in an interesting LMC emission bubble from 4 different UKST H exposures taken with a range of filters/emulsions and exposure times. Figure 2a (top left) is data from a 2 hour Tech Pan exposure with the new filter whilst figure 2b (top right) is an 80 minute equivalent (same emulsion and filter). There is a dramatic increase in information in the longer exposure with no degradation in image quality. Figure 2c (bottom left) gives a 90 minute exposure through the old 120ц… FWHM AAO656 mm H filter with the fast, coarse-grained 098-04 emulsion. This is the worst performing combination for tracing/discovering the fine detailed structure visible in the new exposures. Finally figure 2d (bottom right) is a 3 hour exposure taken with the same AAO656 filter with the standard IIIaF red-sensitive emulsion. Despite the wider passband and longer exposure the depth and detail of the Tech Pan new filter equivalent in figure 3a is far superior.

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Figure 2: Comparison of image quality/depth of the new H Tech Pan combination filter with equivalent UKST images taken with a range of other H filters, emulsions and exposure times. See main text for further details.

б© Copyright Astronomical Society of Australia 1997