A 34 x 34 arcmin field centred on the spiral galaxy M81 has been searched for
emission-line objects using the prime focus wide field camera (WFC) of the 2.54
m Isaac Newton Telescope (La Palma, Spain). A total of 171 candidate planetary
nebulae (PNe) are found, 54 of which are in common with the ones detected by
Jacoby et al. (1989). The behaviour of PNe excitation as a function of
galactocentric distance is examined, and no significant variations are found.
The PNe luminosity function is built for the disk and bulge of M81, separately.
A distance modulus of 27.92+-0.23 mag is found for disk PNe, in good agreement
with previous distance measurements for M81 (Jacoby et al. 1989; Huterer et al.
1995).Comment: 7 pages including 2 tables. A&A accepted; also available at
http://www.iac.es/publicaciones/preprints.htm
