SEARCH FOR BRIGHTNESS FLUCTUATIONS IN THE ZODIACAL LIGHT AT 25 MU-M WITH ISO

We mapped at 25 mu m five approximate to 0.5 degrees x 0.5 degrees fie lds at low, intermediate and high ecliptic latitude with the photomete r onboard the Infrared Space Observatory. The goal was to search for p otential structures in the zodiacal light. No structures were seen in these five sample fields. For an aperture of 3' diameter we find an up per limit for the underlying rms brightness fluctuations of +/-0.2%, w hich corresponds at high ecliptic latitudes to +/-0.04 MJy/sr or +/-25 mJy in the beam.