Near-infrared photometry of the intermediate age open clusters IC 166 and NGC 7789

We present and discuss new photometric data obtained with an IR camera in t he J and K pass-bands for the intermediate age open clusters IC 166 (936 st ars in total) and NGC 7789 (1030 stars in total). IC 166 is a poorly studie d open cluster for which no IR data was available previously, while NGC 778 9 is a well studied open cluster: We show that IC 166 is of intermediate age (about 1.0 Gyr), with a reddenin g E(V-K) approximate to 1.3 (corresponding to E(B-V) = 0.50) and a true dis tance modulus (m - M)(0) = 13.25. These values are significantly different from previous determinations. NGC 7789 is found to be a 1.4 Gyr open cluster. The metallicity derived wit h the method developed by Tiede et al (1997) is found to be closer to the s pectroscopic estimate than previous photometric studies.