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

Survey planning and logistics

The new survey, timely in respect of telescope loading, commenced in April 1997. Unfortunately the filter's 5.5 degree diameter field does not provide contiguous H sky coverage when set on standard 5 degree field centres. This is due to the 1.5 degree overlap between standard UKST 6.56.5 degree fields. A small 1 degree area in the overlap regions is missed. A conservative 4 degree field centre separation was adopted which ensures no gaps in H coverage. About 233 such fields are needed to cover the Southern Galactic Plane. This will then be extended to the outer regions of the Galactic Plane and to declinations from +0 to +15 degrees. Exposures will be of the order of 3 hours and the initial survey region will take about 3 years to complete. Although not sky-limited, the 3 hour exposure times are a good compromise between survey progress and exposure quality, due to the increased likelihood of seeing variations, cloud interruptions and effects of field rotation. The narrow-band nature of the H filter means that the survey could continue in good seeing grey/bright time when the sky is too bright for normal observations. The photometric integrity of the survey is currently being assessed via independent narrow band CCD photometry from the Curtis Schmidt at CTIO and with reference to previously studied objects over a range of UKST fields.

© Copyright Astronomical Society of Australia 1997