Recent tests at the UKST with large-format Kodak Technical Pan 4415 film on a thick estar base have proved to be extremely successful. Deep, sky- limited photographs with excellent image quality and resolution have been obtained. In good seeing these reach a magnitude or more fainter than equivalent IIIa-F plates, and have considerably lower grain noise and greater photometric accuracy. Here we demonstrate quantitatively for the first time the effectiveness of this film for galaxy photometry. In particular, we find that the limiting isophote for surface photometry on an R-band, deep Tech-Pan 4415 film is about 27 Rμ or about 0.2 per cent of the measured sky background. This is over a magnitude lower than normally attained with equivalent R-band IIIa-F plates. Such films therefore have a depth broadly equivalent to ~2-min CCD R exposures on a 4.0-m telescope but with wide-angle (40 square degree) coverage.
- Galaxies: photometry
- Techniques: photometric